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/home/tahkoom/public_html/wp-includes/sodium_compat/src/Core/Curve25519.php
<?php

if (class_exists('ParagonIE_Sodium_Core_Curve25519', false)) {
    return;
}

/**
 * Class ParagonIE_Sodium_Core_Curve25519
 *
 * Implements Curve25519 core functions
 *
 * Based on the ref10 curve25519 code provided by libsodium
 *
 * @ref https://github.com/jedisct1/libsodium/blob/master/src/libsodium/crypto_core/curve25519/ref10/curve25519_ref10.c
 */
abstract class ParagonIE_Sodium_Core_Curve25519 extends ParagonIE_Sodium_Core_Curve25519_H
{
    /**
     * Get a field element of size 10 with a value of 0
     *
     * @internal You should not use this directly from another application
     *
     * @return ParagonIE_Sodium_Core_Curve25519_Fe
     */
    public static function fe_0()
    {
        return ParagonIE_Sodium_Core_Curve25519_Fe::fromArray(
            array(0, 0, 0, 0, 0, 0, 0, 0, 0, 0)
        );
    }

    /**
     * Get a field element of size 10 with a value of 1
     *
     * @internal You should not use this directly from another application
     *
     * @return ParagonIE_Sodium_Core_Curve25519_Fe
     */
    public static function fe_1()
    {
        return ParagonIE_Sodium_Core_Curve25519_Fe::fromArray(
            array(1, 0, 0, 0, 0, 0, 0, 0, 0, 0)
        );
    }

    /**
     * Add two field elements.
     *
     * @internal You should not use this directly from another application
     *
     * @param ParagonIE_Sodium_Core_Curve25519_Fe $f
     * @param ParagonIE_Sodium_Core_Curve25519_Fe $g
     * @return ParagonIE_Sodium_Core_Curve25519_Fe
     * @psalm-suppress MixedAssignment
     * @psalm-suppress MixedOperand
     */
    public static function fe_add(
        ParagonIE_Sodium_Core_Curve25519_Fe $f,
        ParagonIE_Sodium_Core_Curve25519_Fe $g
    ) {
        /** @var array<int, int> $arr */
        $arr = array();
        for ($i = 0; $i < 10; ++$i) {
            $arr[$i] = (int) ($f[$i] + $g[$i]);
        }
        return ParagonIE_Sodium_Core_Curve25519_Fe::fromArray($arr);
    }

    /**
     * Constant-time conditional move.
     *
     * @internal You should not use this directly from another application
     *
     * @param ParagonIE_Sodium_Core_Curve25519_Fe $f
     * @param ParagonIE_Sodium_Core_Curve25519_Fe $g
     * @param int $b
     * @return ParagonIE_Sodium_Core_Curve25519_Fe
     * @psalm-suppress MixedAssignment
     */
    public static function fe_cmov(
        ParagonIE_Sodium_Core_Curve25519_Fe $f,
        ParagonIE_Sodium_Core_Curve25519_Fe $g,
        $b = 0
    ) {
        /** @var array<int, int> $h */
        $h = array();
        $b *= -1;
        for ($i = 0; $i < 10; ++$i) {
            $x = (($f[$i] ^ $g[$i]) & $b);
            $h[$i] = ($f[$i]) ^ $x;
        }
        return ParagonIE_Sodium_Core_Curve25519_Fe::fromArray($h);
    }

    /**
     * Create a copy of a field element.
     *
     * @internal You should not use this directly from another application
     *
     * @param ParagonIE_Sodium_Core_Curve25519_Fe $f
     * @return ParagonIE_Sodium_Core_Curve25519_Fe
     */
    public static function fe_copy(ParagonIE_Sodium_Core_Curve25519_Fe $f)
    {
        $h = clone $f;
        return $h;
    }

    /**
     * Give: 32-byte string.
     * Receive: A field element object to use for internal calculations.
     *
     * @internal You should not use this directly from another application
     *
     * @param string $s
     * @return ParagonIE_Sodium_Core_Curve25519_Fe
     * @throws RangeException
     * @throws TypeError
     */
    public static function fe_frombytes($s)
    {
        if (self::strlen($s) !== 32) {
            throw new RangeException('Expected a 32-byte string.');
        }
        $h0 = self::load_4($s);
        $h1 = self::load_3(self::substr($s, 4, 3)) << 6;
        $h2 = self::load_3(self::substr($s, 7, 3)) << 5;
        $h3 = self::load_3(self::substr($s, 10, 3)) << 3;
        $h4 = self::load_3(self::substr($s, 13, 3)) << 2;
        $h5 = self::load_4(self::substr($s, 16, 4));
        $h6 = self::load_3(self::substr($s, 20, 3)) << 7;
        $h7 = self::load_3(self::substr($s, 23, 3)) << 5;
        $h8 = self::load_3(self::substr($s, 26, 3)) << 4;
        $h9 = (self::load_3(self::substr($s, 29, 3)) & 8388607) << 2;

        $carry9 = ($h9 + (1 << 24)) >> 25;
        $h0 += self::mul($carry9, 19, 5);
        $h9 -= $carry9 << 25;
        $carry1 = ($h1 + (1 << 24)) >> 25;
        $h2 += $carry1;
        $h1 -= $carry1 << 25;
        $carry3 = ($h3 + (1 << 24)) >> 25;
        $h4 += $carry3;
        $h3 -= $carry3 << 25;
        $carry5 = ($h5 + (1 << 24)) >> 25;
        $h6 += $carry5;
        $h5 -= $carry5 << 25;
        $carry7 = ($h7 + (1 << 24)) >> 25;
        $h8 += $carry7;
        $h7 -= $carry7 << 25;

        $carry0 = ($h0 + (1 << 25)) >> 26;
        $h1 += $carry0;
        $h0 -= $carry0 << 26;
        $carry2 = ($h2 + (1 << 25)) >> 26;
        $h3 += $carry2;
        $h2 -= $carry2 << 26;
        $carry4 = ($h4 + (1 << 25)) >> 26;
        $h5 += $carry4;
        $h4 -= $carry4 << 26;
        $carry6 = ($h6 + (1 << 25)) >> 26;
        $h7 += $carry6;
        $h6 -= $carry6 << 26;
        $carry8 = ($h8 + (1 << 25)) >> 26;
        $h9 += $carry8;
        $h8 -= $carry8 << 26;

        return ParagonIE_Sodium_Core_Curve25519_Fe::fromArray(
            array(
                (int) $h0,
                (int) $h1,
                (int) $h2,
                (int) $h3,
                (int) $h4,
                (int) $h5,
                (int) $h6,
                (int) $h7,
                (int) $h8,
                (int) $h9
            )
        );
    }

    /**
     * Convert a field element to a byte string.
     *
     * @internal You should not use this directly from another application
     *
     * @param ParagonIE_Sodium_Core_Curve25519_Fe $h
     * @return string
     */
    public static function fe_tobytes(ParagonIE_Sodium_Core_Curve25519_Fe $h)
    {
        $h0 = (int) $h[0];
        $h1 = (int) $h[1];
        $h2 = (int) $h[2];
        $h3 = (int) $h[3];
        $h4 = (int) $h[4];
        $h5 = (int) $h[5];
        $h6 = (int) $h[6];
        $h7 = (int) $h[7];
        $h8 = (int) $h[8];
        $h9 = (int) $h[9];

        $q = (self::mul($h9, 19, 5) + (1 << 24)) >> 25;
        $q = ($h0 + $q) >> 26;
        $q = ($h1 + $q) >> 25;
        $q = ($h2 + $q) >> 26;
        $q = ($h3 + $q) >> 25;
        $q = ($h4 + $q) >> 26;
        $q = ($h5 + $q) >> 25;
        $q = ($h6 + $q) >> 26;
        $q = ($h7 + $q) >> 25;
        $q = ($h8 + $q) >> 26;
        $q = ($h9 + $q) >> 25;

        $h0 += self::mul($q, 19, 5);

        $carry0 = $h0 >> 26;
        $h1 += $carry0;
        $h0 -= $carry0 << 26;
        $carry1 = $h1 >> 25;
        $h2 += $carry1;
        $h1 -= $carry1 << 25;
        $carry2 = $h2 >> 26;
        $h3 += $carry2;
        $h2 -= $carry2 << 26;
        $carry3 = $h3 >> 25;
        $h4 += $carry3;
        $h3 -= $carry3 << 25;
        $carry4 = $h4 >> 26;
        $h5 += $carry4;
        $h4 -= $carry4 << 26;
        $carry5 = $h5 >> 25;
        $h6 += $carry5;
        $h5 -= $carry5 << 25;
        $carry6 = $h6 >> 26;
        $h7 += $carry6;
        $h6 -= $carry6 << 26;
        $carry7 = $h7 >> 25;
        $h8 += $carry7;
        $h7 -= $carry7 << 25;
        $carry8 = $h8 >> 26;
        $h9 += $carry8;
        $h8 -= $carry8 << 26;
        $carry9 = $h9 >> 25;
        $h9 -= $carry9 << 25;

        /**
         * @var array<int, int>
         */
        $s = array(
            (int) (($h0 >> 0) & 0xff),
            (int) (($h0 >> 8) & 0xff),
            (int) (($h0 >> 16) & 0xff),
            (int) ((($h0 >> 24) | ($h1 << 2)) & 0xff),
            (int) (($h1 >> 6) & 0xff),
            (int) (($h1 >> 14) & 0xff),
            (int) ((($h1 >> 22) | ($h2 << 3)) & 0xff),
            (int) (($h2 >> 5) & 0xff),
            (int) (($h2 >> 13) & 0xff),
            (int) ((($h2 >> 21) | ($h3 << 5)) & 0xff),
            (int) (($h3 >> 3) & 0xff),
            (int) (($h3 >> 11) & 0xff),
            (int) ((($h3 >> 19) | ($h4 << 6)) & 0xff),
            (int) (($h4 >> 2) & 0xff),
            (int) (($h4 >> 10) & 0xff),
            (int) (($h4 >> 18) & 0xff),
            (int) (($h5 >> 0) & 0xff),
            (int) (($h5 >> 8) & 0xff),
            (int) (($h5 >> 16) & 0xff),
            (int) ((($h5 >> 24) | ($h6 << 1)) & 0xff),
            (int) (($h6 >> 7) & 0xff),
            (int) (($h6 >> 15) & 0xff),
            (int) ((($h6 >> 23) | ($h7 << 3)) & 0xff),
            (int) (($h7 >> 5) & 0xff),
            (int) (($h7 >> 13) & 0xff),
            (int) ((($h7 >> 21) | ($h8 << 4)) & 0xff),
            (int) (($h8 >> 4) & 0xff),
            (int) (($h8 >> 12) & 0xff),
            (int) ((($h8 >> 20) | ($h9 << 6)) & 0xff),
            (int) (($h9 >> 2) & 0xff),
            (int) (($h9 >> 10) & 0xff),
            (int) (($h9 >> 18) & 0xff)
        );
        return self::intArrayToString($s);
    }

    /**
     * Is a field element negative? (1 = yes, 0 = no. Used in calculations.)
     *
     * @internal You should not use this directly from another application
     *
     * @param ParagonIE_Sodium_Core_Curve25519_Fe $f
     * @return int
     * @throws SodiumException
     * @throws TypeError
     */
    public static function fe_isnegative(ParagonIE_Sodium_Core_Curve25519_Fe $f)
    {
        $str = self::fe_tobytes($f);
        return (int) (self::chrToInt($str[0]) & 1);
    }

    /**
     * Returns 0 if this field element results in all NUL bytes.
     *
     * @internal You should not use this directly from another application
     *
     * @param ParagonIE_Sodium_Core_Curve25519_Fe $f
     * @return bool
     * @throws SodiumException
     * @throws TypeError
     */
    public static function fe_isnonzero(ParagonIE_Sodium_Core_Curve25519_Fe $f)
    {
        static $zero;
        if ($zero === null) {
            $zero = str_repeat("\x00", 32);
        }
        /** @var string $zero */
        /** @var string $str */
        $str = self::fe_tobytes($f);
        return !self::verify_32($str, (string) $zero);
    }

    /**
     * Multiply two field elements
     *
     * h = f * g
     *
     * @internal You should not use this directly from another application
     *
     * @security Is multiplication a source of timing leaks? If so, can we do
     *           anything to prevent that from happening?
     *
     * @param ParagonIE_Sodium_Core_Curve25519_Fe $f
     * @param ParagonIE_Sodium_Core_Curve25519_Fe $g
     * @return ParagonIE_Sodium_Core_Curve25519_Fe
     */
    public static function fe_mul(
        ParagonIE_Sodium_Core_Curve25519_Fe $f,
        ParagonIE_Sodium_Core_Curve25519_Fe $g
    ) {
        // Ensure limbs aren't oversized.
        $f = self::fe_normalize($f);
        $g = self::fe_normalize($g);
        $f0 = $f[0];
        $f1 = $f[1];
        $f2 = $f[2];
        $f3 = $f[3];
        $f4 = $f[4];
        $f5 = $f[5];
        $f6 = $f[6];
        $f7 = $f[7];
        $f8 = $f[8];
        $f9 = $f[9];
        $g0 = $g[0];
        $g1 = $g[1];
        $g2 = $g[2];
        $g3 = $g[3];
        $g4 = $g[4];
        $g5 = $g[5];
        $g6 = $g[6];
        $g7 = $g[7];
        $g8 = $g[8];
        $g9 = $g[9];
        $g1_19 = self::mul($g1, 19, 5);
        $g2_19 = self::mul($g2, 19, 5);
        $g3_19 = self::mul($g3, 19, 5);
        $g4_19 = self::mul($g4, 19, 5);
        $g5_19 = self::mul($g5, 19, 5);
        $g6_19 = self::mul($g6, 19, 5);
        $g7_19 = self::mul($g7, 19, 5);
        $g8_19 = self::mul($g8, 19, 5);
        $g9_19 = self::mul($g9, 19, 5);
        $f1_2 = $f1 << 1;
        $f3_2 = $f3 << 1;
        $f5_2 = $f5 << 1;
        $f7_2 = $f7 << 1;
        $f9_2 = $f9 << 1;
        $f0g0    = self::mul($f0,    $g0, 26);
        $f0g1    = self::mul($f0,    $g1, 25);
        $f0g2    = self::mul($f0,    $g2, 26);
        $f0g3    = self::mul($f0,    $g3, 25);
        $f0g4    = self::mul($f0,    $g4, 26);
        $f0g5    = self::mul($f0,    $g5, 25);
        $f0g6    = self::mul($f0,    $g6, 26);
        $f0g7    = self::mul($f0,    $g7, 25);
        $f0g8    = self::mul($f0,    $g8, 26);
        $f0g9    = self::mul($f0,    $g9, 26);
        $f1g0    = self::mul($f1,    $g0, 26);
        $f1g1_2  = self::mul($f1_2,  $g1, 25);
        $f1g2    = self::mul($f1,    $g2, 26);
        $f1g3_2  = self::mul($f1_2,  $g3, 25);
        $f1g4    = self::mul($f1,    $g4, 26);
        $f1g5_2  = self::mul($f1_2,  $g5, 25);
        $f1g6    = self::mul($f1,    $g6, 26);
        $f1g7_2  = self::mul($f1_2,  $g7, 25);
        $f1g8    = self::mul($f1,    $g8, 26);
        $f1g9_38 = self::mul($g9_19, $f1_2, 26);
        $f2g0    = self::mul($f2,    $g0, 26);
        $f2g1    = self::mul($f2,    $g1, 25);
        $f2g2    = self::mul($f2,    $g2, 26);
        $f2g3    = self::mul($f2,    $g3, 25);
        $f2g4    = self::mul($f2,    $g4, 26);
        $f2g5    = self::mul($f2,    $g5, 25);
        $f2g6    = self::mul($f2,    $g6, 26);
        $f2g7    = self::mul($f2,    $g7, 25);
        $f2g8_19 = self::mul($g8_19, $f2, 26);
        $f2g9_19 = self::mul($g9_19, $f2, 26);
        $f3g0    = self::mul($f3,    $g0, 26);
        $f3g1_2  = self::mul($f3_2,  $g1, 25);
        $f3g2    = self::mul($f3,    $g2, 26);
        $f3g3_2  = self::mul($f3_2,  $g3, 25);
        $f3g4    = self::mul($f3,    $g4, 26);
        $f3g5_2  = self::mul($f3_2,  $g5, 25);
        $f3g6    = self::mul($f3,    $g6, 26);
        $f3g7_38 = self::mul($g7_19, $f3_2, 26);
        $f3g8_19 = self::mul($g8_19, $f3, 25);
        $f3g9_38 = self::mul($g9_19, $f3_2, 26);
        $f4g0    = self::mul($f4,    $g0, 26);
        $f4g1    = self::mul($f4,    $g1, 25);
        $f4g2    = self::mul($f4,    $g2, 26);
        $f4g3    = self::mul($f4,    $g3, 25);
        $f4g4    = self::mul($f4,    $g4, 26);
        $f4g5    = self::mul($f4,    $g5, 25);
        $f4g6_19 = self::mul($g6_19, $f4, 26);
        $f4g7_19 = self::mul($g7_19, $f4, 26);
        $f4g8_19 = self::mul($g8_19, $f4, 26);
        $f4g9_19 = self::mul($g9_19, $f4, 26);
        $f5g0    = self::mul($f5,    $g0, 26);
        $f5g1_2  = self::mul($f5_2,  $g1, 25);
        $f5g2    = self::mul($f5,    $g2, 26);
        $f5g3_2  = self::mul($f5_2,  $g3, 25);
        $f5g4    = self::mul($f5,    $g4, 26);
        $f5g5_38 = self::mul($g5_19, $f5_2, 26);
        $f5g6_19 = self::mul($g6_19, $f5, 25);
        $f5g7_38 = self::mul($g7_19, $f5_2, 26);
        $f5g8_19 = self::mul($g8_19, $f5, 25);
        $f5g9_38 = self::mul($g9_19, $f5_2, 26);
        $f6g0    = self::mul($f6,    $g0, 26);
        $f6g1    = self::mul($f6,    $g1, 25);
        $f6g2    = self::mul($f6,    $g2, 26);
        $f6g3    = self::mul($f6,    $g3, 25);
        $f6g4_19 = self::mul($g4_19, $f6, 26);
        $f6g5_19 = self::mul($g5_19, $f6, 26);
        $f6g6_19 = self::mul($g6_19, $f6, 26);
        $f6g7_19 = self::mul($g7_19, $f6, 26);
        $f6g8_19 = self::mul($g8_19, $f6, 26);
        $f6g9_19 = self::mul($g9_19, $f6, 26);
        $f7g0    = self::mul($f7,    $g0, 26);
        $f7g1_2  = self::mul($f7_2,  $g1, 25);
        $f7g2    = self::mul($f7,    $g2, 26);
        $f7g3_38 = self::mul($g3_19, $f7_2, 26);
        $f7g4_19 = self::mul($g4_19, $f7, 26);
        $f7g5_38 = self::mul($g5_19, $f7_2, 26);
        $f7g6_19 = self::mul($g6_19, $f7, 25);
        $f7g7_38 = self::mul($g7_19, $f7_2, 26);
        $f7g8_19 = self::mul($g8_19, $f7, 25);
        $f7g9_38 = self::mul($g9_19,$f7_2, 26);
        $f8g0    = self::mul($f8,    $g0, 26);
        $f8g1    = self::mul($f8,    $g1, 25);
        $f8g2_19 = self::mul($g2_19, $f8, 26);
        $f8g3_19 = self::mul($g3_19, $f8, 26);
        $f8g4_19 = self::mul($g4_19, $f8, 26);
        $f8g5_19 = self::mul($g5_19, $f8, 26);
        $f8g6_19 = self::mul($g6_19, $f8, 26);
        $f8g7_19 = self::mul($g7_19, $f8, 26);
        $f8g8_19 = self::mul($g8_19, $f8, 26);
        $f8g9_19 = self::mul($g9_19, $f8, 26);
        $f9g0    = self::mul($f9,    $g0, 26);
        $f9g1_38 = self::mul($g1_19, $f9_2, 26);
        $f9g2_19 = self::mul($g2_19, $f9, 25);
        $f9g3_38 = self::mul($g3_19, $f9_2, 26);
        $f9g4_19 = self::mul($g4_19, $f9, 25);
        $f9g5_38 = self::mul($g5_19, $f9_2, 26);
        $f9g6_19 = self::mul($g6_19, $f9, 25);
        $f9g7_38 = self::mul($g7_19, $f9_2, 26);
        $f9g8_19 = self::mul($g8_19, $f9, 25);
        $f9g9_38 = self::mul($g9_19, $f9_2, 26);

        $h0 = $f0g0 + $f1g9_38 + $f2g8_19 + $f3g7_38 + $f4g6_19 + $f5g5_38 + $f6g4_19 + $f7g3_38 + $f8g2_19 + $f9g1_38;
        $h1 = $f0g1 + $f1g0    + $f2g9_19 + $f3g8_19 + $f4g7_19 + $f5g6_19 + $f6g5_19 + $f7g4_19 + $f8g3_19 + $f9g2_19;
        $h2 = $f0g2 + $f1g1_2  + $f2g0    + $f3g9_38 + $f4g8_19 + $f5g7_38 + $f6g6_19 + $f7g5_38 + $f8g4_19 + $f9g3_38;
        $h3 = $f0g3 + $f1g2    + $f2g1    + $f3g0    + $f4g9_19 + $f5g8_19 + $f6g7_19 + $f7g6_19 + $f8g5_19 + $f9g4_19;
        $h4 = $f0g4 + $f1g3_2  + $f2g2    + $f3g1_2  + $f4g0    + $f5g9_38 + $f6g8_19 + $f7g7_38 + $f8g6_19 + $f9g5_38;
        $h5 = $f0g5 + $f1g4    + $f2g3    + $f3g2    + $f4g1    + $f5g0    + $f6g9_19 + $f7g8_19 + $f8g7_19 + $f9g6_19;
        $h6 = $f0g6 + $f1g5_2  + $f2g4    + $f3g3_2  + $f4g2    + $f5g1_2  + $f6g0    + $f7g9_38 + $f8g8_19 + $f9g7_38;
        $h7 = $f0g7 + $f1g6    + $f2g5    + $f3g4    + $f4g3    + $f5g2    + $f6g1    + $f7g0    + $f8g9_19 + $f9g8_19;
        $h8 = $f0g8 + $f1g7_2  + $f2g6    + $f3g5_2  + $f4g4    + $f5g3_2  + $f6g2    + $f7g1_2  + $f8g0    + $f9g9_38;
        $h9 = $f0g9 + $f1g8    + $f2g7    + $f3g6    + $f4g5    + $f5g4    + $f6g3    + $f7g2    + $f8g1    + $f9g0   ;

        $carry0 = ($h0 + (1 << 25)) >> 26;
        $h1 += $carry0;
        $h0 -= $carry0 << 26;
        $carry4 = ($h4 + (1 << 25)) >> 26;
        $h5 += $carry4;
        $h4 -= $carry4 << 26;

        $carry1 = ($h1 + (1 << 24)) >> 25;
        $h2 += $carry1;
        $h1 -= $carry1 << 25;
        $carry5 = ($h5 + (1 << 24)) >> 25;
        $h6 += $carry5;
        $h5 -= $carry5 << 25;

        $carry2 = ($h2 + (1 << 25)) >> 26;
        $h3 += $carry2;
        $h2 -= $carry2 << 26;
        $carry6 = ($h6 + (1 << 25)) >> 26;
        $h7 += $carry6;
        $h6 -= $carry6 << 26;

        $carry3 = ($h3 + (1 << 24)) >> 25;
        $h4 += $carry3;
        $h3 -= $carry3 << 25;
        $carry7 = ($h7 + (1 << 24)) >> 25;
        $h8 += $carry7;
        $h7 -= $carry7 << 25;

        $carry4 = ($h4 + (1 << 25)) >> 26;
        $h5 += $carry4;
        $h4 -= $carry4 << 26;
        $carry8 = ($h8 + (1 << 25)) >> 26;
        $h9 += $carry8;
        $h8 -= $carry8 << 26;

        $carry9 = ($h9 + (1 << 24)) >> 25;
        $h0 += self::mul($carry9, 19, 5);
        $h9 -= $carry9 << 25;

        $carry0 = ($h0 + (1 << 25)) >> 26;
        $h1 += $carry0;
        $h0 -= $carry0 << 26;

        return self::fe_normalize(
            ParagonIE_Sodium_Core_Curve25519_Fe::fromArray(
                array(
                    (int) $h0,
                    (int) $h1,
                    (int) $h2,
                    (int) $h3,
                    (int) $h4,
                    (int) $h5,
                    (int) $h6,
                    (int) $h7,
                    (int) $h8,
                    (int) $h9
                )
            )
        );
    }

    /**
     * Get the negative values for each piece of the field element.
     *
     * h = -f
     *
     * @internal You should not use this directly from another application
     *
     * @param ParagonIE_Sodium_Core_Curve25519_Fe $f
     * @return ParagonIE_Sodium_Core_Curve25519_Fe
     * @psalm-suppress MixedAssignment
     */
    public static function fe_neg(ParagonIE_Sodium_Core_Curve25519_Fe $f)
    {
        $h = new ParagonIE_Sodium_Core_Curve25519_Fe();
        for ($i = 0; $i < 10; ++$i) {
            $h[$i] = -$f[$i];
        }
        return self::fe_normalize($h);
    }

    /**
     * Square a field element
     *
     * h = f * f
     *
     * @internal You should not use this directly from another application
     *
     * @param ParagonIE_Sodium_Core_Curve25519_Fe $f
     * @return ParagonIE_Sodium_Core_Curve25519_Fe
     */
    public static function fe_sq(ParagonIE_Sodium_Core_Curve25519_Fe $f)
    {
        $f = self::fe_normalize($f);
        $f0 = (int) $f[0];
        $f1 = (int) $f[1];
        $f2 = (int) $f[2];
        $f3 = (int) $f[3];
        $f4 = (int) $f[4];
        $f5 = (int) $f[5];
        $f6 = (int) $f[6];
        $f7 = (int) $f[7];
        $f8 = (int) $f[8];
        $f9 = (int) $f[9];

        $f0_2 = $f0 << 1;
        $f1_2 = $f1 << 1;
        $f2_2 = $f2 << 1;
        $f3_2 = $f3 << 1;
        $f4_2 = $f4 << 1;
        $f5_2 = $f5 << 1;
        $f6_2 = $f6 << 1;
        $f7_2 = $f7 << 1;
        $f5_38 = self::mul($f5, 38, 6);
        $f6_19 = self::mul($f6, 19, 5);
        $f7_38 = self::mul($f7, 38, 6);
        $f8_19 = self::mul($f8, 19, 5);
        $f9_38 = self::mul($f9, 38, 6);
        $f0f0    = self::mul($f0,    $f0,    26);
        $f0f1_2  = self::mul($f0_2,  $f1,    26);
        $f0f2_2  = self::mul($f0_2,  $f2,    26);
        $f0f3_2  = self::mul($f0_2,  $f3,    26);
        $f0f4_2  = self::mul($f0_2,  $f4,    26);
        $f0f5_2  = self::mul($f0_2,  $f5,    26);
        $f0f6_2  = self::mul($f0_2,  $f6,    26);
        $f0f7_2  = self::mul($f0_2,  $f7,    26);
        $f0f8_2  = self::mul($f0_2,  $f8,    26);
        $f0f9_2  = self::mul($f0_2,  $f9,    26);
        $f1f1_2  = self::mul($f1_2,  $f1,    26);
        $f1f2_2  = self::mul($f1_2,  $f2,    26);
        $f1f3_4  = self::mul($f1_2,  $f3_2,  26);
        $f1f4_2  = self::mul($f1_2,  $f4,    26);
        $f1f5_4  = self::mul($f1_2,  $f5_2,  26);
        $f1f6_2  = self::mul($f1_2,  $f6,    26);
        $f1f7_4  = self::mul($f1_2,  $f7_2,  26);
        $f1f8_2  = self::mul($f1_2,  $f8,    26);
        $f1f9_76 = self::mul($f9_38, $f1_2,  27);
        $f2f2    = self::mul($f2,    $f2,    27);
        $f2f3_2  = self::mul($f2_2,  $f3,    27);
        $f2f4_2  = self::mul($f2_2,  $f4,    27);
        $f2f5_2  = self::mul($f2_2,  $f5,    27);
        $f2f6_2  = self::mul($f2_2,  $f6,    27);
        $f2f7_2  = self::mul($f2_2,  $f7,    27);
        $f2f8_38 = self::mul($f8_19, $f2_2,  27);
        $f2f9_38 = self::mul($f9_38, $f2,    26);
        $f3f3_2  = self::mul($f3_2,  $f3,    26);
        $f3f4_2  = self::mul($f3_2,  $f4,    26);
        $f3f5_4  = self::mul($f3_2,  $f5_2,  26);
        $f3f6_2  = self::mul($f3_2,  $f6,    26);
        $f3f7_76 = self::mul($f7_38, $f3_2,  26);
        $f3f8_38 = self::mul($f8_19, $f3_2,  26);
        $f3f9_76 = self::mul($f9_38, $f3_2,  26);
        $f4f4    = self::mul($f4,    $f4,    26);
        $f4f5_2  = self::mul($f4_2,  $f5,    26);
        $f4f6_38 = self::mul($f6_19, $f4_2,  27);
        $f4f7_38 = self::mul($f7_38, $f4,    26);
        $f4f8_38 = self::mul($f8_19, $f4_2,  27);
        $f4f9_38 = self::mul($f9_38, $f4,    26);
        $f5f5_38 = self::mul($f5_38, $f5,    26);
        $f5f6_38 = self::mul($f6_19, $f5_2,  26);
        $f5f7_76 = self::mul($f7_38, $f5_2,  26);
        $f5f8_38 = self::mul($f8_19, $f5_2,  26);
        $f5f9_76 = self::mul($f9_38, $f5_2,  26);
        $f6f6_19 = self::mul($f6_19, $f6,    26);
        $f6f7_38 = self::mul($f7_38, $f6,    26);
        $f6f8_38 = self::mul($f8_19, $f6_2,  27);
        $f6f9_38 = self::mul($f9_38, $f6,    26);
        $f7f7_38 = self::mul($f7_38, $f7,    26);
        $f7f8_38 = self::mul($f8_19, $f7_2,  26);
        $f7f9_76 = self::mul($f9_38, $f7_2,  26);
        $f8f8_19 = self::mul($f8_19, $f8,    26);
        $f8f9_38 = self::mul($f9_38, $f8,    26);
        $f9f9_38 = self::mul($f9_38, $f9,    26);
        $h0 = $f0f0   + $f1f9_76 + $f2f8_38 + $f3f7_76 + $f4f6_38 + $f5f5_38;
        $h1 = $f0f1_2 + $f2f9_38 + $f3f8_38 + $f4f7_38 + $f5f6_38;
        $h2 = $f0f2_2 + $f1f1_2  + $f3f9_76 + $f4f8_38 + $f5f7_76 + $f6f6_19;
        $h3 = $f0f3_2 + $f1f2_2  + $f4f9_38 + $f5f8_38 + $f6f7_38;
        $h4 = $f0f4_2 + $f1f3_4  + $f2f2    + $f5f9_76 + $f6f8_38 + $f7f7_38;
        $h5 = $f0f5_2 + $f1f4_2  + $f2f3_2  + $f6f9_38 + $f7f8_38;
        $h6 = $f0f6_2 + $f1f5_4  + $f2f4_2  + $f3f3_2  + $f7f9_76 + $f8f8_19;
        $h7 = $f0f7_2 + $f1f6_2  + $f2f5_2  + $f3f4_2  + $f8f9_38;
        $h8 = $f0f8_2 + $f1f7_4  + $f2f6_2  + $f3f5_4  + $f4f4    + $f9f9_38;
        $h9 = $f0f9_2 + $f1f8_2  + $f2f7_2  + $f3f6_2  + $f4f5_2;

        $carry0 = ($h0 + (1 << 25)) >> 26;
        $h1 += $carry0;
        $h0 -= $carry0 << 26;
        $carry4 = ($h4 + (1 << 25)) >> 26;
        $h5 += $carry4;
        $h4 -= $carry4 << 26;

        $carry1 = ($h1 + (1 << 24)) >> 25;
        $h2 += $carry1;
        $h1 -= $carry1 << 25;
        $carry5 = ($h5 + (1 << 24)) >> 25;
        $h6 += $carry5;
        $h5 -= $carry5 << 25;

        $carry2 = ($h2 + (1 << 25)) >> 26;
        $h3 += $carry2;
        $h2 -= $carry2 << 26;
        $carry6 = ($h6 + (1 << 25)) >> 26;
        $h7 += $carry6;
        $h6 -= $carry6 << 26;

        $carry3 = ($h3 + (1 << 24)) >> 25;
        $h4 += $carry3;
        $h3 -= $carry3 << 25;
        $carry7 = ($h7 + (1 << 24)) >> 25;
        $h8 += $carry7;
        $h7 -= $carry7 << 25;

        $carry4 = ($h4 + (1 << 25)) >> 26;
        $h5 += $carry4;
        $h4 -= $carry4 << 26;
        $carry8 = ($h8 + (1 << 25)) >> 26;
        $h9 += $carry8;
        $h8 -= $carry8 << 26;

        $carry9 = ($h9 + (1 << 24)) >> 25;
        $h0 += self::mul($carry9, 19, 5);
        $h9 -= $carry9 << 25;

        $carry0 = ($h0 + (1 << 25)) >> 26;
        $h1 += $carry0;
        $h0 -= $carry0 << 26;

        return self::fe_normalize(
            ParagonIE_Sodium_Core_Curve25519_Fe::fromArray(
                array(
                    (int) $h0,
                    (int) $h1,
                    (int) $h2,
                    (int) $h3,
                    (int) $h4,
                    (int) $h5,
                    (int) $h6,
                    (int) $h7,
                    (int) $h8,
                    (int) $h9
                )
            )
        );
    }


    /**
     * Square and double a field element
     *
     * h = 2 * f * f
     *
     * @internal You should not use this directly from another application
     *
     * @param ParagonIE_Sodium_Core_Curve25519_Fe $f
     * @return ParagonIE_Sodium_Core_Curve25519_Fe
     */
    public static function fe_sq2(ParagonIE_Sodium_Core_Curve25519_Fe $f)
    {
        $f = self::fe_normalize($f);
        $f0 = (int) $f[0];
        $f1 = (int) $f[1];
        $f2 = (int) $f[2];
        $f3 = (int) $f[3];
        $f4 = (int) $f[4];
        $f5 = (int) $f[5];
        $f6 = (int) $f[6];
        $f7 = (int) $f[7];
        $f8 = (int) $f[8];
        $f9 = (int) $f[9];

        $f0_2 = $f0 << 1;
        $f1_2 = $f1 << 1;
        $f2_2 = $f2 << 1;
        $f3_2 = $f3 << 1;
        $f4_2 = $f4 << 1;
        $f5_2 = $f5 << 1;
        $f6_2 = $f6 << 1;
        $f7_2 = $f7 << 1;
        $f5_38 = self::mul($f5, 38, 6); /* 1.959375*2^30 */
        $f6_19 = self::mul($f6, 19, 5); /* 1.959375*2^30 */
        $f7_38 = self::mul($f7, 38, 6); /* 1.959375*2^30 */
        $f8_19 = self::mul($f8, 19, 5); /* 1.959375*2^30 */
        $f9_38 = self::mul($f9, 38, 6); /* 1.959375*2^30 */
        $f0f0 = self::mul($f0, $f0, 24);
        $f0f1_2 = self::mul($f0_2, $f1, 24);
        $f0f2_2 = self::mul($f0_2, $f2, 24);
        $f0f3_2 = self::mul($f0_2, $f3, 24);
        $f0f4_2 = self::mul($f0_2, $f4, 24);
        $f0f5_2 = self::mul($f0_2, $f5, 24);
        $f0f6_2 = self::mul($f0_2, $f6, 24);
        $f0f7_2 = self::mul($f0_2, $f7, 24);
        $f0f8_2 = self::mul($f0_2, $f8, 24);
        $f0f9_2 = self::mul($f0_2, $f9, 24);
        $f1f1_2 = self::mul($f1_2,  $f1, 24);
        $f1f2_2 = self::mul($f1_2,  $f2, 24);
        $f1f3_4 = self::mul($f1_2,  $f3_2, 24);
        $f1f4_2 = self::mul($f1_2,  $f4, 24);
        $f1f5_4 = self::mul($f1_2,  $f5_2, 24);
        $f1f6_2 = self::mul($f1_2,  $f6, 24);
        $f1f7_4 = self::mul($f1_2,  $f7_2, 24);
        $f1f8_2 = self::mul($f1_2,  $f8, 24);
        $f1f9_76 = self::mul($f9_38, $f1_2, 24);
        $f2f2 = self::mul($f2,  $f2, 24);
        $f2f3_2 = self::mul($f2_2,  $f3, 24);
        $f2f4_2 = self::mul($f2_2,  $f4, 24);
        $f2f5_2 = self::mul($f2_2,  $f5, 24);
        $f2f6_2 = self::mul($f2_2,  $f6, 24);
        $f2f7_2 = self::mul($f2_2,  $f7, 24);
        $f2f8_38 = self::mul($f8_19, $f2_2, 25);
        $f2f9_38 = self::mul($f9_38, $f2, 24);
        $f3f3_2 = self::mul($f3_2,  $f3, 24);
        $f3f4_2 = self::mul($f3_2,  $f4, 24);
        $f3f5_4 = self::mul($f3_2,  $f5_2, 24);
        $f3f6_2 = self::mul($f3_2,  $f6, 24);
        $f3f7_76 = self::mul($f7_38, $f3_2, 24);
        $f3f8_38 = self::mul($f8_19, $f3_2, 24);
        $f3f9_76 = self::mul($f9_38, $f3_2, 24);
        $f4f4 = self::mul($f4,  $f4, 24);
        $f4f5_2 = self::mul($f4_2,  $f5, 24);
        $f4f6_38 = self::mul($f6_19, $f4_2, 25);
        $f4f7_38 = self::mul($f7_38, $f4, 24);
        $f4f8_38 = self::mul($f8_19, $f4_2, 25);
        $f4f9_38 = self::mul($f9_38, $f4, 24);
        $f5f5_38 = self::mul($f5_38, $f5, 24);
        $f5f6_38 = self::mul($f6_19, $f5_2, 24);
        $f5f7_76 = self::mul($f7_38, $f5_2, 24);
        $f5f8_38 = self::mul($f8_19, $f5_2, 24);
        $f5f9_76 = self::mul($f9_38, $f5_2, 24);
        $f6f6_19 = self::mul($f6_19, $f6, 24);
        $f6f7_38 = self::mul($f7_38, $f6, 24);
        $f6f8_38 = self::mul($f8_19, $f6_2, 25);
        $f6f9_38 = self::mul($f9_38, $f6, 24);
        $f7f7_38 = self::mul($f7_38, $f7, 24);
        $f7f8_38 = self::mul($f8_19, $f7_2, 24);
        $f7f9_76 = self::mul($f9_38, $f7_2, 24);
        $f8f8_19 = self::mul($f8_19, $f8, 24);
        $f8f9_38 = self::mul($f9_38, $f8, 24);
        $f9f9_38 = self::mul($f9_38, $f9, 24);

        $h0 = (int) ($f0f0 + $f1f9_76 + $f2f8_38 + $f3f7_76 + $f4f6_38 + $f5f5_38) << 1;
        $h1 = (int) ($f0f1_2 + $f2f9_38 + $f3f8_38 + $f4f7_38 + $f5f6_38) << 1;
        $h2 = (int) ($f0f2_2 + $f1f1_2  + $f3f9_76 + $f4f8_38 + $f5f7_76 + $f6f6_19) << 1;
        $h3 = (int) ($f0f3_2 + $f1f2_2  + $f4f9_38 + $f5f8_38 + $f6f7_38) << 1;
        $h4 = (int) ($f0f4_2 + $f1f3_4  + $f2f2    + $f5f9_76 + $f6f8_38 + $f7f7_38) << 1;
        $h5 = (int) ($f0f5_2 + $f1f4_2  + $f2f3_2  + $f6f9_38 + $f7f8_38) << 1;
        $h6 = (int) ($f0f6_2 + $f1f5_4  + $f2f4_2  + $f3f3_2  + $f7f9_76 + $f8f8_19) << 1;
        $h7 = (int) ($f0f7_2 + $f1f6_2  + $f2f5_2  + $f3f4_2  + $f8f9_38) << 1;
        $h8 = (int) ($f0f8_2 + $f1f7_4  + $f2f6_2  + $f3f5_4  + $f4f4    + $f9f9_38) << 1;
        $h9 = (int) ($f0f9_2 + $f1f8_2  + $f2f7_2  + $f3f6_2  + $f4f5_2) << 1;

        $carry0 = ($h0 + (1 << 25)) >> 26;
        $h1 += $carry0;
        $h0 -= $carry0 << 26;
        $carry4 = ($h4 + (1 << 25)) >> 26;
        $h5 += $carry4;
        $h4 -= $carry4 << 26;

        $carry1 = ($h1 + (1 << 24)) >> 25;
        $h2 += $carry1;
        $h1 -= $carry1 << 25;
        $carry5 = ($h5 + (1 << 24)) >> 25;
        $h6 += $carry5;
        $h5 -= $carry5 << 25;

        $carry2 = ($h2 + (1 << 25)) >> 26;
        $h3 += $carry2;
        $h2 -= $carry2 << 26;
        $carry6 = ($h6 + (1 << 25)) >> 26;
        $h7 += $carry6;
        $h6 -= $carry6 << 26;

        $carry3 = ($h3 + (1 << 24)) >> 25;
        $h4 += $carry3;
        $h3 -= $carry3 << 25;
        $carry7 = ($h7 + (1 << 24)) >> 25;
        $h8 += $carry7;
        $h7 -= $carry7 << 25;

        $carry4 = ($h4 + (1 << 25)) >> 26;
        $h5 += $carry4;
        $h4 -= $carry4 << 26;
        $carry8 = ($h8 + (1 << 25)) >> 26;
        $h9 += $carry8;
        $h8 -= $carry8 << 26;

        $carry9 = ($h9 + (1 << 24)) >> 25;
        $h0 += self::mul($carry9, 19, 5);
        $h9 -= $carry9 << 25;

        $carry0 = ($h0 + (1 << 25)) >> 26;
        $h1 += $carry0;
        $h0 -= $carry0 << 26;

        return self::fe_normalize(
            ParagonIE_Sodium_Core_Curve25519_Fe::fromArray(
                array(
                    (int) $h0,
                    (int) $h1,
                    (int) $h2,
                    (int) $h3,
                    (int) $h4,
                    (int) $h5,
                    (int) $h6,
                    (int) $h7,
                    (int) $h8,
                    (int) $h9
                )
            )
        );
    }

    /**
     * @internal You should not use this directly from another application
     *
     * @param ParagonIE_Sodium_Core_Curve25519_Fe $Z
     * @return ParagonIE_Sodium_Core_Curve25519_Fe
     */
    public static function fe_invert(ParagonIE_Sodium_Core_Curve25519_Fe $Z)
    {
        $z = clone $Z;
        $t0 = self::fe_sq($z);
        $t1 = self::fe_sq($t0);
        $t1 = self::fe_sq($t1);
        $t1 = self::fe_mul($z, $t1);
        $t0 = self::fe_mul($t0, $t1);
        $t2 = self::fe_sq($t0);
        $t1 = self::fe_mul($t1, $t2);
        $t2 = self::fe_sq($t1);
        for ($i = 1; $i < 5; ++$i) {
            $t2 = self::fe_sq($t2);
        }
        $t1 = self::fe_mul($t2, $t1);
        $t2 = self::fe_sq($t1);
        for ($i = 1; $i < 10; ++$i) {
            $t2 = self::fe_sq($t2);
        }
        $t2 = self::fe_mul($t2, $t1);
        $t3 = self::fe_sq($t2);
        for ($i = 1; $i < 20; ++$i) {
            $t3 = self::fe_sq($t3);
        }
        $t2 = self::fe_mul($t3, $t2);
        $t2 = self::fe_sq($t2);
        for ($i = 1; $i < 10; ++$i) {
            $t2 = self::fe_sq($t2);
        }
        $t1 = self::fe_mul($t2, $t1);
        $t2 = self::fe_sq($t1);
        for ($i = 1; $i < 50; ++$i) {
            $t2 = self::fe_sq($t2);
        }
        $t2 = self::fe_mul($t2, $t1);
        $t3 = self::fe_sq($t2);
        for ($i = 1; $i < 100; ++$i) {
            $t3 = self::fe_sq($t3);
        }
        $t2 = self::fe_mul($t3, $t2);
        $t2 = self::fe_sq($t2);
        for ($i = 1; $i < 50; ++$i) {
            $t2 = self::fe_sq($t2);
        }
        $t1 = self::fe_mul($t2, $t1);
        $t1 = self::fe_sq($t1);
        for ($i = 1; $i < 5; ++$i) {
            $t1 = self::fe_sq($t1);
        }
        return self::fe_mul($t1, $t0);
    }

    /**
     * @internal You should not use this directly from another application
     *
     * @ref https://github.com/jedisct1/libsodium/blob/68564326e1e9dc57ef03746f85734232d20ca6fb/src/libsodium/crypto_core/curve25519/ref10/curve25519_ref10.c#L1054-L1106
     *
     * @param ParagonIE_Sodium_Core_Curve25519_Fe $z
     * @return ParagonIE_Sodium_Core_Curve25519_Fe
     */
    public static function fe_pow22523(ParagonIE_Sodium_Core_Curve25519_Fe $z)
    {
        $z = self::fe_normalize($z);
        # fe_sq(t0, z);
        # fe_sq(t1, t0);
        # fe_sq(t1, t1);
        # fe_mul(t1, z, t1);
        # fe_mul(t0, t0, t1);
        # fe_sq(t0, t0);
        # fe_mul(t0, t1, t0);
        # fe_sq(t1, t0);
        $t0 = self::fe_sq($z);
        $t1 = self::fe_sq($t0);
        $t1 = self::fe_sq($t1);
        $t1 = self::fe_mul($z, $t1);
        $t0 = self::fe_mul($t0, $t1);
        $t0 = self::fe_sq($t0);
        $t0 = self::fe_mul($t1, $t0);
        $t1 = self::fe_sq($t0);

        # for (i = 1; i < 5; ++i) {
        #     fe_sq(t1, t1);
        # }
        for ($i = 1; $i < 5; ++$i) {
            $t1 = self::fe_sq($t1);
        }

        # fe_mul(t0, t1, t0);
        # fe_sq(t1, t0);
        $t0 = self::fe_mul($t1, $t0);
        $t1 = self::fe_sq($t0);

        # for (i = 1; i < 10; ++i) {
        #     fe_sq(t1, t1);
        # }
        for ($i = 1; $i < 10; ++$i) {
            $t1 = self::fe_sq($t1);
        }

        # fe_mul(t1, t1, t0);
        # fe_sq(t2, t1);
        $t1 = self::fe_mul($t1, $t0);
        $t2 = self::fe_sq($t1);

        # for (i = 1; i < 20; ++i) {
        #     fe_sq(t2, t2);
        # }
        for ($i = 1; $i < 20; ++$i) {
            $t2 = self::fe_sq($t2);
        }

        # fe_mul(t1, t2, t1);
        # fe_sq(t1, t1);
        $t1 = self::fe_mul($t2, $t1);
        $t1 = self::fe_sq($t1);

        # for (i = 1; i < 10; ++i) {
        #     fe_sq(t1, t1);
        # }
        for ($i = 1; $i < 10; ++$i) {
            $t1 = self::fe_sq($t1);
        }

        # fe_mul(t0, t1, t0);
        # fe_sq(t1, t0);
        $t0 = self::fe_mul($t1, $t0);
        $t1 = self::fe_sq($t0);

        # for (i = 1; i < 50; ++i) {
        #     fe_sq(t1, t1);
        # }
        for ($i = 1; $i < 50; ++$i) {
            $t1 = self::fe_sq($t1);
        }

        # fe_mul(t1, t1, t0);
        # fe_sq(t2, t1);
        $t1 = self::fe_mul($t1, $t0);
        $t2 = self::fe_sq($t1);

        # for (i = 1; i < 100; ++i) {
        #     fe_sq(t2, t2);
        # }
        for ($i = 1; $i < 100; ++$i) {
            $t2 = self::fe_sq($t2);
        }

        # fe_mul(t1, t2, t1);
        # fe_sq(t1, t1);
        $t1 = self::fe_mul($t2, $t1);
        $t1 = self::fe_sq($t1);

        # for (i = 1; i < 50; ++i) {
        #     fe_sq(t1, t1);
        # }
        for ($i = 1; $i < 50; ++$i) {
            $t1 = self::fe_sq($t1);
        }

        # fe_mul(t0, t1, t0);
        # fe_sq(t0, t0);
        # fe_sq(t0, t0);
        # fe_mul(out, t0, z);
        $t0 = self::fe_mul($t1, $t0);
        $t0 = self::fe_sq($t0);
        $t0 = self::fe_sq($t0);
        return self::fe_mul($t0, $z);
    }

    /**
     * Subtract two field elements.
     *
     * h = f - g
     *
     * Preconditions:
     * |f| bounded by 1.1*2^25,1.1*2^24,1.1*2^25,1.1*2^24,etc.
     * |g| bounded by 1.1*2^25,1.1*2^24,1.1*2^25,1.1*2^24,etc.
     *
     * Postconditions:
     * |h| bounded by 1.1*2^26,1.1*2^25,1.1*2^26,1.1*2^25,etc.
     *
     * @internal You should not use this directly from another application
     *
     * @param ParagonIE_Sodium_Core_Curve25519_Fe $f
     * @param ParagonIE_Sodium_Core_Curve25519_Fe $g
     * @return ParagonIE_Sodium_Core_Curve25519_Fe
     * @psalm-suppress MixedOperand
     */
    public static function fe_sub(ParagonIE_Sodium_Core_Curve25519_Fe $f, ParagonIE_Sodium_Core_Curve25519_Fe $g)
    {
        return self::fe_normalize(
            ParagonIE_Sodium_Core_Curve25519_Fe::fromArray(
                array(
                    (int) ($f[0] - $g[0]),
                    (int) ($f[1] - $g[1]),
                    (int) ($f[2] - $g[2]),
                    (int) ($f[3] - $g[3]),
                    (int) ($f[4] - $g[4]),
                    (int) ($f[5] - $g[5]),
                    (int) ($f[6] - $g[6]),
                    (int) ($f[7] - $g[7]),
                    (int) ($f[8] - $g[8]),
                    (int) ($f[9] - $g[9])
                )
            )
        );
    }

    /**
     * Add two group elements.
     *
     * r = p + q
     *
     * @internal You should not use this directly from another application
     *
     * @param ParagonIE_Sodium_Core_Curve25519_Ge_P3 $p
     * @param ParagonIE_Sodium_Core_Curve25519_Ge_Cached $q
     * @return ParagonIE_Sodium_Core_Curve25519_Ge_P1p1
     */
    public static function ge_add(
        ParagonIE_Sodium_Core_Curve25519_Ge_P3 $p,
        ParagonIE_Sodium_Core_Curve25519_Ge_Cached $q
    ) {
        $r = new ParagonIE_Sodium_Core_Curve25519_Ge_P1p1();
        $r->X = self::fe_add($p->Y, $p->X);
        $r->Y = self::fe_sub($p->Y, $p->X);
        $r->Z = self::fe_mul($r->X, $q->YplusX);
        $r->Y = self::fe_mul($r->Y, $q->YminusX);
        $r->T = self::fe_mul($q->T2d, $p->T);
        $r->X = self::fe_mul($p->Z, $q->Z);
        $t0   = self::fe_add($r->X, $r->X);
        $r->X = self::fe_sub($r->Z, $r->Y);
        $r->Y = self::fe_add($r->Z, $r->Y);
        $r->Z = self::fe_add($t0, $r->T);
        $r->T = self::fe_sub($t0, $r->T);
        return $r;
    }

    /**
     * @internal You should not use this directly from another application
     *
     * @ref https://github.com/jedisct1/libsodium/blob/157c4a80c13b117608aeae12178b2d38825f9f8f/src/libsodium/crypto_core/curve25519/ref10/curve25519_ref10.c#L1185-L1215
     * @param string $a
     * @return array<int, mixed>
     * @throws SodiumException
     * @throws TypeError
     */
    public static function slide($a)
    {
        if (self::strlen($a) < 256) {
            if (self::strlen($a) < 16) {
                $a = str_pad($a, 256, '0', STR_PAD_RIGHT);
            }
        }
        /** @var array<int, int> $r */
        $r = array();

        /** @var int $i */
        for ($i = 0; $i < 256; ++$i) {
            $r[$i] = (int) (
                1 & (
                    self::chrToInt($a[(int) ($i >> 3)])
                        >>
                    ($i & 7)
                )
            );
        }

        for ($i = 0;$i < 256;++$i) {
            if ($r[$i]) {
                for ($b = 1;$b <= 6 && $i + $b < 256;++$b) {
                    if ($r[$i + $b]) {
                        if ($r[$i] + ($r[$i + $b] << $b) <= 15) {
                            $r[$i] += $r[$i + $b] << $b;
                            $r[$i + $b] = 0;
                        } elseif ($r[$i] - ($r[$i + $b] << $b) >= -15) {
                            $r[$i] -= $r[$i + $b] << $b;
                            for ($k = $i + $b; $k < 256; ++$k) {
                                if (!$r[$k]) {
                                    $r[$k] = 1;
                                    break;
                                }
                                $r[$k] = 0;
                            }
                        } else {
                            break;
                        }
                    }
                }
            }
        }
        return $r;
    }

    /**
     * @internal You should not use this directly from another application
     *
     * @param string $s
     * @return ParagonIE_Sodium_Core_Curve25519_Ge_P3
     * @throws SodiumException
     * @throws TypeError
     */
    public static function ge_frombytes_negate_vartime($s)
    {
        static $d = null;
        if (!$d) {
            $d = ParagonIE_Sodium_Core_Curve25519_Fe::fromArray(self::$d);
        }

        # fe_frombytes(h->Y,s);
        # fe_1(h->Z);
        $h = new ParagonIE_Sodium_Core_Curve25519_Ge_P3(
            self::fe_0(),
            self::fe_frombytes($s),
            self::fe_1()
        );

        # fe_sq(u,h->Y);
        # fe_mul(v,u,d);
        # fe_sub(u,u,h->Z);       /* u = y^2-1 */
        # fe_add(v,v,h->Z);       /* v = dy^2+1 */
        $u = self::fe_sq($h->Y);
        /** @var ParagonIE_Sodium_Core_Curve25519_Fe $d */
        $v = self::fe_mul($u, $d);
        $u = self::fe_sub($u, $h->Z); /* u =  y^2 - 1 */
        $v = self::fe_add($v, $h->Z); /* v = dy^2 + 1 */

        # fe_sq(v3,v);
        # fe_mul(v3,v3,v);        /* v3 = v^3 */
        # fe_sq(h->X,v3);
        # fe_mul(h->X,h->X,v);
        # fe_mul(h->X,h->X,u);    /* x = uv^7 */
        $v3 = self::fe_sq($v);
        $v3 = self::fe_mul($v3, $v); /* v3 = v^3 */
        $h->X = self::fe_sq($v3);
        $h->X = self::fe_mul($h->X, $v);
        $h->X = self::fe_mul($h->X, $u); /* x = uv^7 */

        # fe_pow22523(h->X,h->X); /* x = (uv^7)^((q-5)/8) */
        # fe_mul(h->X,h->X,v3);
        # fe_mul(h->X,h->X,u);    /* x = uv^3(uv^7)^((q-5)/8) */
        $h->X = self::fe_pow22523($h->X); /* x = (uv^7)^((q-5)/8) */
        $h->X = self::fe_mul($h->X, $v3);
        $h->X = self::fe_mul($h->X, $u); /* x = uv^3(uv^7)^((q-5)/8) */

        # fe_sq(vxx,h->X);
        # fe_mul(vxx,vxx,v);
        # fe_sub(check,vxx,u);    /* vx^2-u */
        $vxx = self::fe_sq($h->X);
        $vxx = self::fe_mul($vxx, $v);
        $check = self::fe_sub($vxx, $u); /* vx^2 - u */

        # if (fe_isnonzero(check)) {
        #     fe_add(check,vxx,u);  /* vx^2+u */
        #     if (fe_isnonzero(check)) {
        #         return -1;
        #     }
        #     fe_mul(h->X,h->X,sqrtm1);
        # }
        if (self::fe_isnonzero($check)) {
            $check = self::fe_add($vxx, $u); /* vx^2 + u */
            if (self::fe_isnonzero($check)) {
                throw new RangeException('Internal check failed.');
            }
            $h->X = self::fe_mul(
                $h->X,
                ParagonIE_Sodium_Core_Curve25519_Fe::fromArray(self::$sqrtm1)
            );
        }

        # if (fe_isnegative(h->X) == (s[31] >> 7)) {
        #     fe_neg(h->X,h->X);
        # }
        $i = self::chrToInt($s[31]);
        if (self::fe_isnegative($h->X) === ($i >> 7)) {
            $h->X = self::fe_neg($h->X);
        }

        # fe_mul(h->T,h->X,h->Y);
        $h->T = self::fe_mul($h->X, $h->Y);
        return $h;
    }

    /**
     * @internal You should not use this directly from another application
     *
     * @param ParagonIE_Sodium_Core_Curve25519_Ge_P1p1 $R
     * @param ParagonIE_Sodium_Core_Curve25519_Ge_P3 $p
     * @param ParagonIE_Sodium_Core_Curve25519_Ge_Precomp $q
     * @return ParagonIE_Sodium_Core_Curve25519_Ge_P1p1
     */
    public static function ge_madd(
        ParagonIE_Sodium_Core_Curve25519_Ge_P1p1 $R,
        ParagonIE_Sodium_Core_Curve25519_Ge_P3 $p,
        ParagonIE_Sodium_Core_Curve25519_Ge_Precomp $q
    ) {
        $r = clone $R;
        $r->X = self::fe_add($p->Y, $p->X);
        $r->Y = self::fe_sub($p->Y, $p->X);
        $r->Z = self::fe_mul($r->X, $q->yplusx);
        $r->Y = self::fe_mul($r->Y, $q->yminusx);
        $r->T = self::fe_mul($q->xy2d, $p->T);
        $t0 = self::fe_add(clone $p->Z, clone $p->Z);
        $r->X = self::fe_sub($r->Z, $r->Y);
        $r->Y = self::fe_add($r->Z, $r->Y);
        $r->Z = self::fe_add($t0, $r->T);
        $r->T = self::fe_sub($t0, $r->T);

        return $r;
    }

    /**
     * @internal You should not use this directly from another application
     *
     * @param ParagonIE_Sodium_Core_Curve25519_Ge_P1p1 $R
     * @param ParagonIE_Sodium_Core_Curve25519_Ge_P3 $p
     * @param ParagonIE_Sodium_Core_Curve25519_Ge_Precomp $q
     * @return ParagonIE_Sodium_Core_Curve25519_Ge_P1p1
     */
    public static function ge_msub(
        ParagonIE_Sodium_Core_Curve25519_Ge_P1p1 $R,
        ParagonIE_Sodium_Core_Curve25519_Ge_P3 $p,
        ParagonIE_Sodium_Core_Curve25519_Ge_Precomp $q
    ) {
        $r = clone $R;

        $r->X = self::fe_add($p->Y, $p->X);
        $r->Y = self::fe_sub($p->Y, $p->X);
        $r->Z = self::fe_mul($r->X, $q->yminusx);
        $r->Y = self::fe_mul($r->Y, $q->yplusx);
        $r->T = self::fe_mul($q->xy2d, $p->T);
        $t0 = self::fe_add($p->Z, $p->Z);
        $r->X = self::fe_sub($r->Z, $r->Y);
        $r->Y = self::fe_add($r->Z, $r->Y);
        $r->Z = self::fe_sub($t0, $r->T);
        $r->T = self::fe_add($t0, $r->T);

        return $r;
    }

    /**
     * @internal You should not use this directly from another application
     *
     * @param ParagonIE_Sodium_Core_Curve25519_Ge_P1p1 $p
     * @return ParagonIE_Sodium_Core_Curve25519_Ge_P2
     */
    public static function ge_p1p1_to_p2(ParagonIE_Sodium_Core_Curve25519_Ge_P1p1 $p)
    {
        $r = new ParagonIE_Sodium_Core_Curve25519_Ge_P2();
        $r->X = self::fe_mul($p->X, $p->T);
        $r->Y = self::fe_mul($p->Y, $p->Z);
        $r->Z = self::fe_mul($p->Z, $p->T);
        return $r;
    }

    /**
     * @internal You should not use this directly from another application
     *
     * @param ParagonIE_Sodium_Core_Curve25519_Ge_P1p1 $p
     * @return ParagonIE_Sodium_Core_Curve25519_Ge_P3
     */
    public static function ge_p1p1_to_p3(ParagonIE_Sodium_Core_Curve25519_Ge_P1p1 $p)
    {
        $r = new ParagonIE_Sodium_Core_Curve25519_Ge_P3();
        $r->X = self::fe_mul($p->X, $p->T);
        $r->Y = self::fe_mul($p->Y, $p->Z);
        $r->Z = self::fe_mul($p->Z, $p->T);
        $r->T = self::fe_mul($p->X, $p->Y);
        return $r;
    }

    /**
     * @internal You should not use this directly from another application
     *
     * @return ParagonIE_Sodium_Core_Curve25519_Ge_P2
     */
    public static function ge_p2_0()
    {
        return new ParagonIE_Sodium_Core_Curve25519_Ge_P2(
            self::fe_0(),
            self::fe_1(),
            self::fe_1()
        );
    }

    /**
     * @internal You should not use this directly from another application
     *
     * @param ParagonIE_Sodium_Core_Curve25519_Ge_P2 $p
     * @return ParagonIE_Sodium_Core_Curve25519_Ge_P1p1
     */
    public static function ge_p2_dbl(ParagonIE_Sodium_Core_Curve25519_Ge_P2 $p)
    {
        $r = new ParagonIE_Sodium_Core_Curve25519_Ge_P1p1();

        $r->X = self::fe_sq($p->X);
        $r->Z = self::fe_sq($p->Y);
        $r->T = self::fe_sq2($p->Z);
        $r->Y = self::fe_add($p->X, $p->Y);
        $t0   = self::fe_sq($r->Y);
        $r->Y = self::fe_add($r->Z, $r->X);
        $r->Z = self::fe_sub($r->Z, $r->X);
        $r->X = self::fe_sub($t0, $r->Y);
        $r->T = self::fe_sub($r->T, $r->Z);

        return $r;
    }

    /**
     * @internal You should not use this directly from another application
     *
     * @return ParagonIE_Sodium_Core_Curve25519_Ge_P3
     */
    public static function ge_p3_0()
    {
        return new ParagonIE_Sodium_Core_Curve25519_Ge_P3(
            self::fe_0(),
            self::fe_1(),
            self::fe_1(),
            self::fe_0()
        );
    }

    /**
     * @internal You should not use this directly from another application
     *
     * @param ParagonIE_Sodium_Core_Curve25519_Ge_P3 $p
     * @return ParagonIE_Sodium_Core_Curve25519_Ge_Cached
     */
    public static function ge_p3_to_cached(ParagonIE_Sodium_Core_Curve25519_Ge_P3 $p)
    {
        static $d2 = null;
        if ($d2 === null) {
            $d2 = ParagonIE_Sodium_Core_Curve25519_Fe::fromArray(self::$d2);
        }
        /** @var ParagonIE_Sodium_Core_Curve25519_Fe $d2 */
        $r = new ParagonIE_Sodium_Core_Curve25519_Ge_Cached();
        $r->YplusX = self::fe_add($p->Y, $p->X);
        $r->YminusX = self::fe_sub($p->Y, $p->X);
        $r->Z = self::fe_copy($p->Z);
        $r->T2d = self::fe_mul($p->T, $d2);
        return $r;
    }

    /**
     * @internal You should not use this directly from another application
     *
     * @param ParagonIE_Sodium_Core_Curve25519_Ge_P3 $p
     * @return ParagonIE_Sodium_Core_Curve25519_Ge_P2
     */
    public static function ge_p3_to_p2(ParagonIE_Sodium_Core_Curve25519_Ge_P3 $p)
    {
        return new ParagonIE_Sodium_Core_Curve25519_Ge_P2(
            self::fe_copy($p->X),
            self::fe_copy($p->Y),
            self::fe_copy($p->Z)
        );
    }

    /**
     * @internal You should not use this directly from another application
     *
     * @param ParagonIE_Sodium_Core_Curve25519_Ge_P3 $h
     * @return string
     * @throws SodiumException
     * @throws TypeError
     */
    public static function ge_p3_tobytes(ParagonIE_Sodium_Core_Curve25519_Ge_P3 $h)
    {
        $recip = self::fe_invert($h->Z);
        $x = self::fe_mul($h->X, $recip);
        $y = self::fe_mul($h->Y, $recip);
        $s = self::fe_tobytes($y);
        $s[31] = self::intToChr(
            self::chrToInt($s[31]) ^ (self::fe_isnegative($x) << 7)
        );
        return $s;
    }

    /**
     * @internal You should not use this directly from another application
     *
     * @param ParagonIE_Sodium_Core_Curve25519_Ge_P3 $p
     * @return ParagonIE_Sodium_Core_Curve25519_Ge_P1p1
     */
    public static function ge_p3_dbl(ParagonIE_Sodium_Core_Curve25519_Ge_P3 $p)
    {
        $q = self::ge_p3_to_p2($p);
        return self::ge_p2_dbl($q);
    }

    /**
     * @return ParagonIE_Sodium_Core_Curve25519_Ge_Precomp
     */
    public static function ge_precomp_0()
    {
        return new ParagonIE_Sodium_Core_Curve25519_Ge_Precomp(
            self::fe_1(),
            self::fe_1(),
            self::fe_0()
        );
    }

    /**
     * @internal You should not use this directly from another application
     *
     * @param int $b
     * @param int $c
     * @return int
     */
    public static function equal($b, $c)
    {
        return (int) ((($b ^ $c) - 1) >> 31) & 1;
    }

    /**
     * @internal You should not use this directly from another application
     *
     * @param int|string $char
     * @return int (1 = yes, 0 = no)
     * @throws SodiumException
     * @throws TypeError
     */
    public static function negative($char)
    {
        if (is_int($char)) {
            return ($char >> 63) & 1;
        }
        $x = self::chrToInt(self::substr($char, 0, 1));
        return (int) ($x >> 63);
    }

    /**
     * Conditional move
     *
     * @internal You should not use this directly from another application
     *
     * @param ParagonIE_Sodium_Core_Curve25519_Ge_Precomp $t
     * @param ParagonIE_Sodium_Core_Curve25519_Ge_Precomp $u
     * @param int $b
     * @return ParagonIE_Sodium_Core_Curve25519_Ge_Precomp
     */
    public static function cmov(
        ParagonIE_Sodium_Core_Curve25519_Ge_Precomp $t,
        ParagonIE_Sodium_Core_Curve25519_Ge_Precomp $u,
        $b
    ) {
        if (!is_int($b)) {
            throw new InvalidArgumentException('Expected an integer.');
        }
        return new ParagonIE_Sodium_Core_Curve25519_Ge_Precomp(
            self::fe_cmov($t->yplusx,  $u->yplusx,  $b),
            self::fe_cmov($t->yminusx, $u->yminusx, $b),
            self::fe_cmov($t->xy2d,    $u->xy2d,    $b)
        );
    }

    /**
     * @param ParagonIE_Sodium_Core_Curve25519_Ge_Cached $t
     * @param ParagonIE_Sodium_Core_Curve25519_Ge_Cached $u
     * @param int $b
     * @return ParagonIE_Sodium_Core_Curve25519_Ge_Cached
     */
    public static function ge_cmov_cached(
        ParagonIE_Sodium_Core_Curve25519_Ge_Cached $t,
        ParagonIE_Sodium_Core_Curve25519_Ge_Cached $u,
        $b
    ) {
        $b &= 1;
        $ret = new ParagonIE_Sodium_Core_Curve25519_Ge_Cached();
        $ret->YplusX  = self::fe_cmov($t->YplusX,  $u->YplusX,  $b);
        $ret->YminusX = self::fe_cmov($t->YminusX, $u->YminusX, $b);
        $ret->Z       = self::fe_cmov($t->Z,       $u->Z,       $b);
        $ret->T2d     = self::fe_cmov($t->T2d,     $u->T2d,     $b);
        return $ret;
    }

    /**
     * @param ParagonIE_Sodium_Core_Curve25519_Ge_Cached[] $cached
     * @param int $b
     * @return ParagonIE_Sodium_Core_Curve25519_Ge_Cached
     * @throws SodiumException
     */
    public static function ge_cmov8_cached(array $cached, $b)
    {
        // const unsigned char bnegative = negative(b);
        // const unsigned char babs      = b - (((-bnegative) & b) * ((signed char) 1 << 1));
        $bnegative = self::negative($b);
        $babs = $b - (((-$bnegative) & $b) << 1);

        // ge25519_cached_0(t);
        $t = new ParagonIE_Sodium_Core_Curve25519_Ge_Cached(
            self::fe_1(),
            self::fe_1(),
            self::fe_1(),
            self::fe_0()
        );

        // ge25519_cmov_cached(t, &cached[0], equal(babs, 1));
        // ge25519_cmov_cached(t, &cached[1], equal(babs, 2));
        // ge25519_cmov_cached(t, &cached[2], equal(babs, 3));
        // ge25519_cmov_cached(t, &cached[3], equal(babs, 4));
        // ge25519_cmov_cached(t, &cached[4], equal(babs, 5));
        // ge25519_cmov_cached(t, &cached[5], equal(babs, 6));
        // ge25519_cmov_cached(t, &cached[6], equal(babs, 7));
        // ge25519_cmov_cached(t, &cached[7], equal(babs, 8));
        for ($x = 0; $x < 8; ++$x) {
            $t = self::ge_cmov_cached($t, $cached[$x], self::equal($babs, $x + 1));
        }

        // fe25519_copy(minust.YplusX, t->YminusX);
        // fe25519_copy(minust.YminusX, t->YplusX);
        // fe25519_copy(minust.Z, t->Z);
        // fe25519_neg(minust.T2d, t->T2d);
        $minust = new ParagonIE_Sodium_Core_Curve25519_Ge_Cached(
            self::fe_copy($t->YminusX),
            self::fe_copy($t->YplusX),
            self::fe_copy($t->Z),
            self::fe_neg($t->T2d)
        );
        return self::ge_cmov_cached($t, $minust, $bnegative);
    }

    /**
     * @internal You should not use this directly from another application
     *
     * @param int $pos
     * @param int $b
     * @return ParagonIE_Sodium_Core_Curve25519_Ge_Precomp
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     * @psalm-suppress MixedArrayAccess
     * @psalm-suppress MixedArrayOffset
     */
    public static function ge_select($pos = 0, $b = 0)
    {
        static $base = null;
        if ($base === null) {
            $base = array();
            /** @var int $i */
            foreach (self::$base as $i => $bas) {
                for ($j = 0; $j < 8; ++$j) {
                    $base[$i][$j] = new ParagonIE_Sodium_Core_Curve25519_Ge_Precomp(
                        ParagonIE_Sodium_Core_Curve25519_Fe::fromArray($bas[$j][0]),
                        ParagonIE_Sodium_Core_Curve25519_Fe::fromArray($bas[$j][1]),
                        ParagonIE_Sodium_Core_Curve25519_Fe::fromArray($bas[$j][2])
                    );
                }
            }
        }
        /** @var array<int, array<int, ParagonIE_Sodium_Core_Curve25519_Ge_Precomp>> $base */
        if (!is_int($pos)) {
            throw new InvalidArgumentException('Position must be an integer');
        }
        if ($pos < 0 || $pos > 31) {
            throw new RangeException('Position is out of range [0, 31]');
        }

        $bnegative = self::negative($b);
        $babs = $b - (((-$bnegative) & $b) << 1);

        $t = self::ge_precomp_0();
        for ($i = 0; $i < 8; ++$i) {
            $t = self::cmov(
                $t,
                $base[$pos][$i],
                self::equal($babs, $i + 1)
            );
        }
        $minusT = new ParagonIE_Sodium_Core_Curve25519_Ge_Precomp(
            self::fe_copy($t->yminusx),
            self::fe_copy($t->yplusx),
            self::fe_neg($t->xy2d)
        );
        return self::cmov($t, $minusT, $bnegative);
    }

    /**
     * Subtract two group elements.
     *
     * r = p - q
     *
     * @internal You should not use this directly from another application
     *
     * @param ParagonIE_Sodium_Core_Curve25519_Ge_P3 $p
     * @param ParagonIE_Sodium_Core_Curve25519_Ge_Cached $q
     * @return ParagonIE_Sodium_Core_Curve25519_Ge_P1p1
     */
    public static function ge_sub(
        ParagonIE_Sodium_Core_Curve25519_Ge_P3 $p,
        ParagonIE_Sodium_Core_Curve25519_Ge_Cached $q
    ) {
        $r = new ParagonIE_Sodium_Core_Curve25519_Ge_P1p1();

        $r->X = self::fe_add($p->Y, $p->X);
        $r->Y = self::fe_sub($p->Y, $p->X);
        $r->Z = self::fe_mul($r->X, $q->YminusX);
        $r->Y = self::fe_mul($r->Y, $q->YplusX);
        $r->T = self::fe_mul($q->T2d, $p->T);
        $r->X = self::fe_mul($p->Z, $q->Z);
        $t0 = self::fe_add($r->X, $r->X);
        $r->X = self::fe_sub($r->Z, $r->Y);
        $r->Y = self::fe_add($r->Z, $r->Y);
        $r->Z = self::fe_sub($t0, $r->T);
        $r->T = self::fe_add($t0, $r->T);

        return $r;
    }

    /**
     * Convert a group element to a byte string.
     *
     * @param ParagonIE_Sodium_Core_Curve25519_Ge_P2 $h
     * @return string
     * @throws SodiumException
     * @throws TypeError
     */
    public static function ge_tobytes(ParagonIE_Sodium_Core_Curve25519_Ge_P2 $h)
    {
        $recip = self::fe_invert($h->Z);
        $x = self::fe_mul($h->X, $recip);
        $y = self::fe_mul($h->Y, $recip);
        $s = self::fe_tobytes($y);
        $s[31] = self::intToChr(
            self::chrToInt($s[31]) ^ (self::fe_isnegative($x) << 7)
        );
        return $s;
    }

    /**
     * @internal You should not use this directly from another application
     *
     * @param string $a
     * @param ParagonIE_Sodium_Core_Curve25519_Ge_P3 $A
     * @param string $b
     * @return ParagonIE_Sodium_Core_Curve25519_Ge_P2
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     * @psalm-suppress MixedArrayAccess
     */
    public static function ge_double_scalarmult_vartime(
        $a,
        ParagonIE_Sodium_Core_Curve25519_Ge_P3 $A,
        $b
    ) {
        /** @var array<int, ParagonIE_Sodium_Core_Curve25519_Ge_Cached> $Ai */
        $Ai = array();

        /** @var array<int, ParagonIE_Sodium_Core_Curve25519_Ge_Precomp> $Bi */
        static $Bi = array();
        if (!$Bi) {
            for ($i = 0; $i < 8; ++$i) {
                $Bi[$i] = new ParagonIE_Sodium_Core_Curve25519_Ge_Precomp(
                    ParagonIE_Sodium_Core_Curve25519_Fe::fromArray(self::$base2[$i][0]),
                    ParagonIE_Sodium_Core_Curve25519_Fe::fromArray(self::$base2[$i][1]),
                    ParagonIE_Sodium_Core_Curve25519_Fe::fromArray(self::$base2[$i][2])
                );
            }
        }
        for ($i = 0; $i < 8; ++$i) {
            $Ai[$i] = new ParagonIE_Sodium_Core_Curve25519_Ge_Cached(
                self::fe_0(),
                self::fe_0(),
                self::fe_0(),
                self::fe_0()
            );
        }

        # slide(aslide,a);
        # slide(bslide,b);
        /** @var array<int, int> $aslide */
        $aslide = self::slide($a);
        /** @var array<int, int> $bslide */
        $bslide = self::slide($b);

        # ge_p3_to_cached(&Ai[0],A);
        # ge_p3_dbl(&t,A); ge_p1p1_to_p3(&A2,&t);
        $Ai[0] = self::ge_p3_to_cached($A);
        $t = self::ge_p3_dbl($A);
        $A2 = self::ge_p1p1_to_p3($t);

        # ge_add(&t,&A2,&Ai[0]); ge_p1p1_to_p3(&u,&t); ge_p3_to_cached(&Ai[1],&u);
        # ge_add(&t,&A2,&Ai[1]); ge_p1p1_to_p3(&u,&t); ge_p3_to_cached(&Ai[2],&u);
        # ge_add(&t,&A2,&Ai[2]); ge_p1p1_to_p3(&u,&t); ge_p3_to_cached(&Ai[3],&u);
        # ge_add(&t,&A2,&Ai[3]); ge_p1p1_to_p3(&u,&t); ge_p3_to_cached(&Ai[4],&u);
        # ge_add(&t,&A2,&Ai[4]); ge_p1p1_to_p3(&u,&t); ge_p3_to_cached(&Ai[5],&u);
        # ge_add(&t,&A2,&Ai[5]); ge_p1p1_to_p3(&u,&t); ge_p3_to_cached(&Ai[6],&u);
        # ge_add(&t,&A2,&Ai[6]); ge_p1p1_to_p3(&u,&t); ge_p3_to_cached(&Ai[7],&u);
        for ($i = 0; $i < 7; ++$i) {
            $t = self::ge_add($A2, $Ai[$i]);
            $u = self::ge_p1p1_to_p3($t);
            $Ai[$i + 1] = self::ge_p3_to_cached($u);
        }

        # ge_p2_0(r);
        $r = self::ge_p2_0();

        # for (i = 255;i >= 0;--i) {
        #     if (aslide[i] || bslide[i]) break;
        # }
        $i = 255;
        for (; $i >= 0; --$i) {
            if ($aslide[$i] || $bslide[$i]) {
                break;
            }
        }

        # for (;i >= 0;--i) {
        for (; $i >= 0; --$i) {
            # ge_p2_dbl(&t,r);
            $t = self::ge_p2_dbl($r);

            # if (aslide[i] > 0) {
            if ($aslide[$i] > 0) {
                # ge_p1p1_to_p3(&u,&t);
                # ge_add(&t,&u,&Ai[aslide[i]/2]);
                $u = self::ge_p1p1_to_p3($t);
                $t = self::ge_add(
                    $u,
                    $Ai[(int) floor($aslide[$i] / 2)]
                );
            # } else if (aslide[i] < 0) {
            } elseif ($aslide[$i] < 0) {
                # ge_p1p1_to_p3(&u,&t);
                # ge_sub(&t,&u,&Ai[(-aslide[i])/2]);
                $u = self::ge_p1p1_to_p3($t);
                $t = self::ge_sub(
                    $u,
                    $Ai[(int) floor(-$aslide[$i] / 2)]
                );
            }

            # if (bslide[i] > 0) {
            if ($bslide[$i] > 0) {
                /** @var int $index */
                $index = (int) floor($bslide[$i] / 2);
                # ge_p1p1_to_p3(&u,&t);
                # ge_madd(&t,&u,&Bi[bslide[i]/2]);
                $u = self::ge_p1p1_to_p3($t);
                $t = self::ge_madd($t, $u, $Bi[$index]);
            # } else if (bslide[i] < 0) {
            } elseif ($bslide[$i] < 0) {
                /** @var int $index */
                $index = (int) floor(-$bslide[$i] / 2);
                # ge_p1p1_to_p3(&u,&t);
                # ge_msub(&t,&u,&Bi[(-bslide[i])/2]);
                $u = self::ge_p1p1_to_p3($t);
                $t = self::ge_msub($t, $u, $Bi[$index]);
            }
            # ge_p1p1_to_p2(r,&t);
            $r = self::ge_p1p1_to_p2($t);
        }
        return $r;
    }

    /**
     * @internal You should not use this directly from another application
     *
     * @param string $a
     * @param ParagonIE_Sodium_Core_Curve25519_Ge_P3 $p
     * @return ParagonIE_Sodium_Core_Curve25519_Ge_P3
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedAssignment
     * @psalm-suppress MixedOperand
     */
    public static function ge_scalarmult($a, $p)
    {
        $e = array_fill(0, 64, 0);

        /** @var ParagonIE_Sodium_Core_Curve25519_Ge_Cached[] $pi */
        $pi = array();

        //        ge25519_p3_to_cached(&pi[1 - 1], p);   /* p */
        $pi[0] = self::ge_p3_to_cached($p);

        //        ge25519_p3_dbl(&t2, p);
        //        ge25519_p1p1_to_p3(&p2, &t2);
        //        ge25519_p3_to_cached(&pi[2 - 1], &p2); /* 2p = 2*p */
        $t2 = self::ge_p3_dbl($p);
        $p2 = self::ge_p1p1_to_p3($t2);
        $pi[1] = self::ge_p3_to_cached($p2);

        //        ge25519_add_cached(&t3, p, &pi[2 - 1]);
        //        ge25519_p1p1_to_p3(&p3, &t3);
        //        ge25519_p3_to_cached(&pi[3 - 1], &p3); /* 3p = 2p+p */
        $t3 = self::ge_add($p, $pi[1]);
        $p3 = self::ge_p1p1_to_p3($t3);
        $pi[2] = self::ge_p3_to_cached($p3);

        //        ge25519_p3_dbl(&t4, &p2);
        //        ge25519_p1p1_to_p3(&p4, &t4);
        //        ge25519_p3_to_cached(&pi[4 - 1], &p4); /* 4p = 2*2p */
        $t4 = self::ge_p3_dbl($p2);
        $p4 = self::ge_p1p1_to_p3($t4);
        $pi[3] = self::ge_p3_to_cached($p4);

        //        ge25519_add_cached(&t5, p, &pi[4 - 1]);
        //        ge25519_p1p1_to_p3(&p5, &t5);
        //        ge25519_p3_to_cached(&pi[5 - 1], &p5); /* 5p = 4p+p */
        $t5 = self::ge_add($p, $pi[3]);
        $p5 = self::ge_p1p1_to_p3($t5);
        $pi[4] = self::ge_p3_to_cached($p5);

        //        ge25519_p3_dbl(&t6, &p3);
        //        ge25519_p1p1_to_p3(&p6, &t6);
        //        ge25519_p3_to_cached(&pi[6 - 1], &p6); /* 6p = 2*3p */
        $t6 = self::ge_p3_dbl($p3);
        $p6 = self::ge_p1p1_to_p3($t6);
        $pi[5] = self::ge_p3_to_cached($p6);

        //        ge25519_add_cached(&t7, p, &pi[6 - 1]);
        //        ge25519_p1p1_to_p3(&p7, &t7);
        //        ge25519_p3_to_cached(&pi[7 - 1], &p7); /* 7p = 6p+p */
        $t7 = self::ge_add($p, $pi[5]);
        $p7 = self::ge_p1p1_to_p3($t7);
        $pi[6] = self::ge_p3_to_cached($p7);

        //        ge25519_p3_dbl(&t8, &p4);
        //        ge25519_p1p1_to_p3(&p8, &t8);
        //        ge25519_p3_to_cached(&pi[8 - 1], &p8); /* 8p = 2*4p */
        $t8 = self::ge_p3_dbl($p4);
        $p8 = self::ge_p1p1_to_p3($t8);
        $pi[7] = self::ge_p3_to_cached($p8);


        //        for (i = 0; i < 32; ++i) {
        //            e[2 * i + 0] = (a[i] >> 0) & 15;
        //            e[2 * i + 1] = (a[i] >> 4) & 15;
        //        }
        for ($i = 0; $i < 32; ++$i) {
            $e[($i << 1)    ] =  self::chrToInt($a[$i]) & 15;
            $e[($i << 1) + 1] = (self::chrToInt($a[$i]) >> 4) & 15;
        }
        //        /* each e[i] is between 0 and 15 */
        //        /* e[63] is between 0 and 7 */

        //        carry = 0;
        //        for (i = 0; i < 63; ++i) {
        //            e[i] += carry;
        //            carry = e[i] + 8;
        //            carry >>= 4;
        //            e[i] -= carry * ((signed char) 1 << 4);
        //        }
        $carry = 0;
        for ($i = 0; $i < 63; ++$i) {
            $e[$i] += $carry;
            $carry = $e[$i] + 8;
            $carry >>= 4;
            $e[$i] -= $carry << 4;
        }
        //        e[63] += carry;
        //        /* each e[i] is between -8 and 8 */
        $e[63] += $carry;

        //        ge25519_p3_0(h);
        $h = self::ge_p3_0();

        //        for (i = 63; i != 0; i--) {
        for ($i = 63; $i != 0; --$i) {
            // ge25519_cmov8_cached(&t, pi, e[i]);
            $t = self::ge_cmov8_cached($pi, $e[$i]);
            // ge25519_add_cached(&r, h, &t);
            $r = self::ge_add($h, $t);

            // ge25519_p1p1_to_p2(&s, &r);
            // ge25519_p2_dbl(&r, &s);
            // ge25519_p1p1_to_p2(&s, &r);
            // ge25519_p2_dbl(&r, &s);
            // ge25519_p1p1_to_p2(&s, &r);
            // ge25519_p2_dbl(&r, &s);
            // ge25519_p1p1_to_p2(&s, &r);
            // ge25519_p2_dbl(&r, &s);
            $s = self::ge_p1p1_to_p2($r);
            $r = self::ge_p2_dbl($s);
            $s = self::ge_p1p1_to_p2($r);
            $r = self::ge_p2_dbl($s);
            $s = self::ge_p1p1_to_p2($r);
            $r = self::ge_p2_dbl($s);
            $s = self::ge_p1p1_to_p2($r);
            $r = self::ge_p2_dbl($s);

            // ge25519_p1p1_to_p3(h, &r);  /* *16 */
            $h = self::ge_p1p1_to_p3($r); /* *16 */
        }

        //        ge25519_cmov8_cached(&t, pi, e[i]);
        //        ge25519_add_cached(&r, h, &t);
        //        ge25519_p1p1_to_p3(h, &r);
        $t = self::ge_cmov8_cached($pi, $e[0]);
        $r = self::ge_add($h, $t);
        return self::ge_p1p1_to_p3($r);
    }

    /**
     * @internal You should not use this directly from another application
     *
     * @param string $a
     * @return ParagonIE_Sodium_Core_Curve25519_Ge_P3
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedAssignment
     * @psalm-suppress MixedOperand
     */
    public static function ge_scalarmult_base($a)
    {
        /** @var array<int, int> $e */
        $e = array();
        $r = new ParagonIE_Sodium_Core_Curve25519_Ge_P1p1();

        for ($i = 0; $i < 32; ++$i) {
            $dbl = (int) $i << 1;
            $e[$dbl] = (int) self::chrToInt($a[$i]) & 15;
            $e[$dbl + 1] = (int) (self::chrToInt($a[$i]) >> 4) & 15;
        }

        $carry = 0;
        for ($i = 0; $i < 63; ++$i) {
            $e[$i] += $carry;
            $carry = $e[$i] + 8;
            $carry >>= 4;
            $e[$i] -= $carry << 4;
        }
        $e[63] += (int) $carry;

        $h = self::ge_p3_0();

        for ($i = 1; $i < 64; $i += 2) {
            $t = self::ge_select((int) floor($i / 2), (int) $e[$i]);
            $r = self::ge_madd($r, $h, $t);
            $h = self::ge_p1p1_to_p3($r);
        }

        $r = self::ge_p3_dbl($h);

        $s = self::ge_p1p1_to_p2($r);
        $r = self::ge_p2_dbl($s);
        $s = self::ge_p1p1_to_p2($r);
        $r = self::ge_p2_dbl($s);
        $s = self::ge_p1p1_to_p2($r);
        $r = self::ge_p2_dbl($s);

        $h = self::ge_p1p1_to_p3($r);

        for ($i = 0; $i < 64; $i += 2) {
            $t = self::ge_select($i >> 1, (int) $e[$i]);
            $r = self::ge_madd($r, $h, $t);
            $h = self::ge_p1p1_to_p3($r);
        }
        return $h;
    }

    /**
     * Calculates (ab + c) mod l
     * where l = 2^252 + 27742317777372353535851937790883648493
     *
     * @internal You should not use this directly from another application
     *
     * @param string $a
     * @param string $b
     * @param string $c
     * @return string
     * @throws TypeError
     */
    public static function sc_muladd($a, $b, $c)
    {
        $a0 = 2097151 & self::load_3(self::substr($a, 0, 3));
        $a1 = 2097151 & (self::load_4(self::substr($a, 2, 4)) >> 5);
        $a2 = 2097151 & (self::load_3(self::substr($a, 5, 3)) >> 2);
        $a3 = 2097151 & (self::load_4(self::substr($a, 7, 4)) >> 7);
        $a4 = 2097151 & (self::load_4(self::substr($a, 10, 4)) >> 4);
        $a5 = 2097151 & (self::load_3(self::substr($a, 13, 3)) >> 1);
        $a6 = 2097151 & (self::load_4(self::substr($a, 15, 4)) >> 6);
        $a7 = 2097151 & (self::load_3(self::substr($a, 18, 3)) >> 3);
        $a8 = 2097151 & self::load_3(self::substr($a, 21, 3));
        $a9 = 2097151 & (self::load_4(self::substr($a, 23, 4)) >> 5);
        $a10 = 2097151 & (self::load_3(self::substr($a, 26, 3)) >> 2);
        $a11 = (self::load_4(self::substr($a, 28, 4)) >> 7);

        $b0 = 2097151 & self::load_3(self::substr($b, 0, 3));
        $b1 = 2097151 & (self::load_4(self::substr($b, 2, 4)) >> 5);
        $b2 = 2097151 & (self::load_3(self::substr($b, 5, 3)) >> 2);
        $b3 = 2097151 & (self::load_4(self::substr($b, 7, 4)) >> 7);
        $b4 = 2097151 & (self::load_4(self::substr($b, 10, 4)) >> 4);
        $b5 = 2097151 & (self::load_3(self::substr($b, 13, 3)) >> 1);
        $b6 = 2097151 & (self::load_4(self::substr($b, 15, 4)) >> 6);
        $b7 = 2097151 & (self::load_3(self::substr($b, 18, 3)) >> 3);
        $b8 = 2097151 & self::load_3(self::substr($b, 21, 3));
        $b9 = 2097151 & (self::load_4(self::substr($b, 23, 4)) >> 5);
        $b10 = 2097151 & (self::load_3(self::substr($b, 26, 3)) >> 2);
        $b11 = (self::load_4(self::substr($b, 28, 4)) >> 7);

        $c0 = 2097151 & self::load_3(self::substr($c, 0, 3));
        $c1 = 2097151 & (self::load_4(self::substr($c, 2, 4)) >> 5);
        $c2 = 2097151 & (self::load_3(self::substr($c, 5, 3)) >> 2);
        $c3 = 2097151 & (self::load_4(self::substr($c, 7, 4)) >> 7);
        $c4 = 2097151 & (self::load_4(self::substr($c, 10, 4)) >> 4);
        $c5 = 2097151 & (self::load_3(self::substr($c, 13, 3)) >> 1);
        $c6 = 2097151 & (self::load_4(self::substr($c, 15, 4)) >> 6);
        $c7 = 2097151 & (self::load_3(self::substr($c, 18, 3)) >> 3);
        $c8 = 2097151 & self::load_3(self::substr($c, 21, 3));
        $c9 = 2097151 & (self::load_4(self::substr($c, 23, 4)) >> 5);
        $c10 = 2097151 & (self::load_3(self::substr($c, 26, 3)) >> 2);
        $c11 = (self::load_4(self::substr($c, 28, 4)) >> 7);

        /* Can't really avoid the pyramid here: */
        $s0 = $c0 + self::mul($a0, $b0, 24);
        $s1 = $c1 + self::mul($a0, $b1, 24) + self::mul($a1, $b0, 24);
        $s2 = $c2 + self::mul($a0, $b2, 24) + self::mul($a1, $b1, 24) + self::mul($a2, $b0, 24);
        $s3 = $c3 + self::mul($a0, $b3, 24) + self::mul($a1, $b2, 24) + self::mul($a2, $b1, 24) + self::mul($a3, $b0, 24);
        $s4 = $c4 + self::mul($a0, $b4, 24) + self::mul($a1, $b3, 24) + self::mul($a2, $b2, 24) + self::mul($a3, $b1, 24) +
               self::mul($a4, $b0, 24);
        $s5 = $c5 + self::mul($a0, $b5, 24) + self::mul($a1, $b4, 24) + self::mul($a2, $b3, 24) + self::mul($a3, $b2, 24) +
               self::mul($a4, $b1, 24) + self::mul($a5, $b0, 24);
        $s6 = $c6 + self::mul($a0, $b6, 24) + self::mul($a1, $b5, 24) + self::mul($a2, $b4, 24) + self::mul($a3, $b3, 24) +
               self::mul($a4, $b2, 24) + self::mul($a5, $b1, 24) + self::mul($a6, $b0, 24);
        $s7 = $c7 + self::mul($a0, $b7, 24) + self::mul($a1, $b6, 24) + self::mul($a2, $b5, 24) + self::mul($a3, $b4, 24) +
               self::mul($a4, $b3, 24) + self::mul($a5, $b2, 24) + self::mul($a6, $b1, 24) + self::mul($a7, $b0, 24);
        $s8 = $c8 + self::mul($a0, $b8, 24) + self::mul($a1, $b7, 24) + self::mul($a2, $b6, 24) + self::mul($a3, $b5, 24) +
               self::mul($a4, $b4, 24) + self::mul($a5, $b3, 24) + self::mul($a6, $b2, 24) + self::mul($a7, $b1, 24) +
               self::mul($a8, $b0, 24);
        $s9 = $c9 + self::mul($a0, $b9, 24) + self::mul($a1, $b8, 24) + self::mul($a2, $b7, 24) + self::mul($a3, $b6, 24) +
               self::mul($a4, $b5, 24) + self::mul($a5, $b4, 24) + self::mul($a6, $b3, 24) + self::mul($a7, $b2, 24) +
               self::mul($a8, $b1, 24) + self::mul($a9, $b0, 24);
        $s10 = $c10 + self::mul($a0, $b10, 24) + self::mul($a1, $b9, 24) + self::mul($a2, $b8, 24) + self::mul($a3, $b7, 24) +
               self::mul($a4, $b6, 24) + self::mul($a5, $b5, 24) + self::mul($a6, $b4, 24) + self::mul($a7, $b3, 24) +
               self::mul($a8, $b2, 24) + self::mul($a9, $b1, 24) + self::mul($a10, $b0, 24);
        $s11 = $c11 + self::mul($a0, $b11, 24) + self::mul($a1, $b10, 24) + self::mul($a2, $b9, 24) + self::mul($a3, $b8, 24) +
               self::mul($a4, $b7, 24) + self::mul($a5, $b6, 24) + self::mul($a6, $b5, 24) + self::mul($a7, $b4, 24) +
               self::mul($a8, $b3, 24) + self::mul($a9, $b2, 24) + self::mul($a10, $b1, 24) + self::mul($a11, $b0, 24);
        $s12 = self::mul($a1, $b11, 24) + self::mul($a2, $b10, 24) + self::mul($a3, $b9, 24) + self::mul($a4, $b8, 24) +
               self::mul($a5, $b7, 24) + self::mul($a6, $b6, 24) + self::mul($a7, $b5, 24) + self::mul($a8, $b4, 24) +
               self::mul($a9, $b3, 24) + self::mul($a10, $b2, 24) + self::mul($a11, $b1, 24);
        $s13 = self::mul($a2, $b11, 24) + self::mul($a3, $b10, 24) + self::mul($a4, $b9, 24) + self::mul($a5, $b8, 24) +
               self::mul($a6, $b7, 24) + self::mul($a7, $b6, 24) + self::mul($a8, $b5, 24) + self::mul($a9, $b4, 24) +
               self::mul($a10, $b3, 24) + self::mul($a11, $b2, 24);
        $s14 = self::mul($a3, $b11, 24) + self::mul($a4, $b10, 24) + self::mul($a5, $b9, 24) + self::mul($a6, $b8, 24) +
               self::mul($a7, $b7, 24) + self::mul($a8, $b6, 24) + self::mul($a9, $b5, 24) + self::mul($a10, $b4, 24) +
               self::mul($a11, $b3, 24);
        $s15 = self::mul($a4, $b11, 24) + self::mul($a5, $b10, 24) + self::mul($a6, $b9, 24) + self::mul($a7, $b8, 24) +
               self::mul($a8, $b7, 24) + self::mul($a9, $b6, 24) + self::mul($a10, $b5, 24) + self::mul($a11, $b4, 24);
        $s16 = self::mul($a5, $b11, 24) + self::mul($a6, $b10, 24) + self::mul($a7, $b9, 24) + self::mul($a8, $b8, 24) +
               self::mul($a9, $b7, 24) + self::mul($a10, $b6, 24) + self::mul($a11, $b5, 24);
        $s17 = self::mul($a6, $b11, 24) + self::mul($a7, $b10, 24) + self::mul($a8, $b9, 24) + self::mul($a9, $b8, 24) +
               self::mul($a10, $b7, 24) + self::mul($a11, $b6, 24);
        $s18 = self::mul($a7, $b11, 24) + self::mul($a8, $b10, 24) + self::mul($a9, $b9, 24) + self::mul($a10, $b8, 24) +
               self::mul($a11, $b7, 24);
        $s19 = self::mul($a8, $b11, 24) + self::mul($a9, $b10, 24) + self::mul($a10, $b9, 24) + self::mul($a11, $b8, 24);
        $s20 = self::mul($a9, $b11, 24) + self::mul($a10, $b10, 24) + self::mul($a11, $b9, 24);
        $s21 = self::mul($a10, $b11, 24) + self::mul($a11, $b10, 24);
        $s22 = self::mul($a11, $b11, 24);
        $s23 = 0;

        $carry0 = ($s0 + (1 << 20)) >> 21;
        $s1 += $carry0;
        $s0 -= $carry0 << 21;
        $carry2 = ($s2 + (1 << 20)) >> 21;
        $s3 += $carry2;
        $s2 -= $carry2 << 21;
        $carry4 = ($s4 + (1 << 20)) >> 21;
        $s5 += $carry4;
        $s4 -= $carry4 << 21;
        $carry6 = ($s6 + (1 << 20)) >> 21;
        $s7 += $carry6;
        $s6 -= $carry6 << 21;
        $carry8 = ($s8 + (1 << 20)) >> 21;
        $s9 += $carry8;
        $s8 -= $carry8 << 21;
        $carry10 = ($s10 + (1 << 20)) >> 21;
        $s11 += $carry10;
        $s10 -= $carry10 << 21;
        $carry12 = ($s12 + (1 << 20)) >> 21;
        $s13 += $carry12;
        $s12 -= $carry12 << 21;
        $carry14 = ($s14 + (1 << 20)) >> 21;
        $s15 += $carry14;
        $s14 -= $carry14 << 21;
        $carry16 = ($s16 + (1 << 20)) >> 21;
        $s17 += $carry16;
        $s16 -= $carry16 << 21;
        $carry18 = ($s18 + (1 << 20)) >> 21;
        $s19 += $carry18;
        $s18 -= $carry18 << 21;
        $carry20 = ($s20 + (1 << 20)) >> 21;
        $s21 += $carry20;
        $s20 -= $carry20 << 21;
        $carry22 = ($s22 + (1 << 20)) >> 21;
        $s23 += $carry22;
        $s22 -= $carry22 << 21;

        $carry1 = ($s1 + (1 << 20)) >> 21;
        $s2 += $carry1;
        $s1 -= $carry1 << 21;
        $carry3 = ($s3 + (1 << 20)) >> 21;
        $s4 += $carry3;
        $s3 -= $carry3 << 21;
        $carry5 = ($s5 + (1 << 20)) >> 21;
        $s6 += $carry5;
        $s5 -= $carry5 << 21;
        $carry7 = ($s7 + (1 << 20)) >> 21;
        $s8 += $carry7;
        $s7 -= $carry7 << 21;
        $carry9 = ($s9 + (1 << 20)) >> 21;
        $s10 += $carry9;
        $s9 -= $carry9 << 21;
        $carry11 = ($s11 + (1 << 20)) >> 21;
        $s12 += $carry11;
        $s11 -= $carry11 << 21;
        $carry13 = ($s13 + (1 << 20)) >> 21;
        $s14 += $carry13;
        $s13 -= $carry13 << 21;
        $carry15 = ($s15 + (1 << 20)) >> 21;
        $s16 += $carry15;
        $s15 -= $carry15 << 21;
        $carry17 = ($s17 + (1 << 20)) >> 21;
        $s18 += $carry17;
        $s17 -= $carry17 << 21;
        $carry19 = ($s19 + (1 << 20)) >> 21;
        $s20 += $carry19;
        $s19 -= $carry19 << 21;
        $carry21 = ($s21 + (1 << 20)) >> 21;
        $s22 += $carry21;
        $s21 -= $carry21 << 21;

        $s11 += self::mul($s23, 666643, 20);
        $s12 += self::mul($s23, 470296, 19);
        $s13 += self::mul($s23, 654183, 20);
        $s14 -= self::mul($s23, 997805, 20);
        $s15 += self::mul($s23, 136657, 18);
        $s16 -= self::mul($s23, 683901, 20);

        $s10 += self::mul($s22, 666643, 20);
        $s11 += self::mul($s22, 470296, 19);
        $s12 += self::mul($s22, 654183, 20);
        $s13 -= self::mul($s22, 997805, 20);
        $s14 += self::mul($s22, 136657, 18);
        $s15 -= self::mul($s22, 683901, 20);

        $s9  += self::mul($s21,  666643, 20);
        $s10 += self::mul($s21,  470296, 19);
        $s11 += self::mul($s21,  654183, 20);
        $s12 -= self::mul($s21,  997805, 20);
        $s13 += self::mul($s21,  136657, 18);
        $s14 -= self::mul($s21,  683901, 20);

        $s8  += self::mul($s20,  666643, 20);
        $s9  += self::mul($s20,  470296, 19);
        $s10 += self::mul($s20,  654183, 20);
        $s11 -= self::mul($s20,  997805, 20);
        $s12 += self::mul($s20,  136657, 18);
        $s13 -= self::mul($s20,  683901, 20);

        $s7  += self::mul($s19,  666643, 20);
        $s8  += self::mul($s19,  470296, 19);
        $s9  += self::mul($s19,  654183, 20);
        $s10 -= self::mul($s19,  997805, 20);
        $s11 += self::mul($s19,  136657, 18);
        $s12 -= self::mul($s19,  683901, 20);

        $s6  += self::mul($s18,  666643, 20);
        $s7  += self::mul($s18,  470296, 19);
        $s8  += self::mul($s18,  654183, 20);
        $s9  -= self::mul($s18,  997805, 20);
        $s10 += self::mul($s18,  136657, 18);
        $s11 -= self::mul($s18,  683901, 20);

        $carry6 = ($s6 + (1 << 20)) >> 21;
        $s7 += $carry6;
        $s6 -= $carry6 << 21;
        $carry8 = ($s8 + (1 << 20)) >> 21;
        $s9 += $carry8;
        $s8 -= $carry8 << 21;
        $carry10 = ($s10 + (1 << 20)) >> 21;
        $s11 += $carry10;
        $s10 -= $carry10 << 21;
        $carry12 = ($s12 + (1 << 20)) >> 21;
        $s13 += $carry12;
        $s12 -= $carry12 << 21;
        $carry14 = ($s14 + (1 << 20)) >> 21;
        $s15 += $carry14;
        $s14 -= $carry14 << 21;
        $carry16 = ($s16 + (1 << 20)) >> 21;
        $s17 += $carry16;
        $s16 -= $carry16 << 21;

        $carry7 = ($s7 + (1 << 20)) >> 21;
        $s8 += $carry7;
        $s7 -= $carry7 << 21;
        $carry9 = ($s9 + (1 << 20)) >> 21;
        $s10 += $carry9;
        $s9 -= $carry9 << 21;
        $carry11 = ($s11 + (1 << 20)) >> 21;
        $s12 += $carry11;
        $s11 -= $carry11 << 21;
        $carry13 = ($s13 + (1 << 20)) >> 21;
        $s14 += $carry13;
        $s13 -= $carry13 << 21;
        $carry15 = ($s15 + (1 << 20)) >> 21;
        $s16 += $carry15;
        $s15 -= $carry15 << 21;

        $s5  += self::mul($s17,  666643, 20);
        $s6  += self::mul($s17,  470296, 19);
        $s7  += self::mul($s17,  654183, 20);
        $s8  -= self::mul($s17,  997805, 20);
        $s9  += self::mul($s17,  136657, 18);
        $s10 -= self::mul($s17,  683901, 20);

        $s4 += self::mul($s16,  666643, 20);
        $s5 += self::mul($s16,  470296, 19);
        $s6 += self::mul($s16,  654183, 20);
        $s7 -= self::mul($s16,  997805, 20);
        $s8 += self::mul($s16,  136657, 18);
        $s9 -= self::mul($s16,  683901, 20);

        $s3 += self::mul($s15,  666643, 20);
        $s4 += self::mul($s15,  470296, 19);
        $s5 += self::mul($s15,  654183, 20);
        $s6 -= self::mul($s15,  997805, 20);
        $s7 += self::mul($s15,  136657, 18);
        $s8 -= self::mul($s15,  683901, 20);

        $s2 += self::mul($s14,  666643, 20);
        $s3 += self::mul($s14,  470296, 19);
        $s4 += self::mul($s14,  654183, 20);
        $s5 -= self::mul($s14,  997805, 20);
        $s6 += self::mul($s14,  136657, 18);
        $s7 -= self::mul($s14,  683901, 20);

        $s1 += self::mul($s13,  666643, 20);
        $s2 += self::mul($s13,  470296, 19);
        $s3 += self::mul($s13,  654183, 20);
        $s4 -= self::mul($s13,  997805, 20);
        $s5 += self::mul($s13,  136657, 18);
        $s6 -= self::mul($s13,  683901, 20);

        $s0 += self::mul($s12,  666643, 20);
        $s1 += self::mul($s12,  470296, 19);
        $s2 += self::mul($s12,  654183, 20);
        $s3 -= self::mul($s12,  997805, 20);
        $s4 += self::mul($s12,  136657, 18);
        $s5 -= self::mul($s12,  683901, 20);
        $s12 = 0;

        $carry0 = ($s0 + (1 << 20)) >> 21;
        $s1 += $carry0;
        $s0 -= $carry0 << 21;
        $carry2 = ($s2 + (1 << 20)) >> 21;
        $s3 += $carry2;
        $s2 -= $carry2 << 21;
        $carry4 = ($s4 + (1 << 20)) >> 21;
        $s5 += $carry4;
        $s4 -= $carry4 << 21;
        $carry6 = ($s6 + (1 << 20)) >> 21;
        $s7 += $carry6;
        $s6 -= $carry6 << 21;
        $carry8 = ($s8 + (1 << 20)) >> 21;
        $s9 += $carry8;
        $s8 -= $carry8 << 21;
        $carry10 = ($s10 + (1 << 20)) >> 21;
        $s11 += $carry10;
        $s10 -= $carry10 << 21;

        $carry1 = ($s1 + (1 << 20)) >> 21;
        $s2 += $carry1;
        $s1 -= $carry1 << 21;
        $carry3 = ($s3 + (1 << 20)) >> 21;
        $s4 += $carry3;
        $s3 -= $carry3 << 21;
        $carry5 = ($s5 + (1 << 20)) >> 21;
        $s6 += $carry5;
        $s5 -= $carry5 << 21;
        $carry7 = ($s7 + (1 << 20)) >> 21;
        $s8 += $carry7;
        $s7 -= $carry7 << 21;
        $carry9 = ($s9 + (1 << 20)) >> 21;
        $s10 += $carry9;
        $s9 -= $carry9 << 21;
        $carry11 = ($s11 + (1 << 20)) >> 21;
        $s12 += $carry11;
        $s11 -= $carry11 << 21;

        $s0 += self::mul($s12,  666643, 20);
        $s1 += self::mul($s12,  470296, 19);
        $s2 += self::mul($s12,  654183, 20);
        $s3 -= self::mul($s12,  997805, 20);
        $s4 += self::mul($s12,  136657, 18);
        $s5 -= self::mul($s12,  683901, 20);
        $s12 = 0;

        $carry0 = $s0 >> 21;
        $s1 += $carry0;
        $s0 -= $carry0 << 21;
        $carry1 = $s1 >> 21;
        $s2 += $carry1;
        $s1 -= $carry1 << 21;
        $carry2 = $s2 >> 21;
        $s3 += $carry2;
        $s2 -= $carry2 << 21;
        $carry3 = $s3 >> 21;
        $s4 += $carry3;
        $s3 -= $carry3 << 21;
        $carry4 = $s4 >> 21;
        $s5 += $carry4;
        $s4 -= $carry4 << 21;
        $carry5 = $s5 >> 21;
        $s6 += $carry5;
        $s5 -= $carry5 << 21;
        $carry6 = $s6 >> 21;
        $s7 += $carry6;
        $s6 -= $carry6 << 21;
        $carry7 = $s7 >> 21;
        $s8 += $carry7;
        $s7 -= $carry7 << 21;
        $carry8 = $s8 >> 21;
        $s9 += $carry8;
        $s8 -= $carry8 << 21;
        $carry9 = $s9 >> 21;
        $s10 += $carry9;
        $s9 -= $carry9 << 21;
        $carry10 = $s10 >> 21;
        $s11 += $carry10;
        $s10 -= $carry10 << 21;
        $carry11 = $s11 >> 21;
        $s12 += $carry11;
        $s11 -= $carry11 << 21;

        $s0 += self::mul($s12,  666643, 20);
        $s1 += self::mul($s12,  470296, 19);
        $s2 += self::mul($s12,  654183, 20);
        $s3 -= self::mul($s12,  997805, 20);
        $s4 += self::mul($s12,  136657, 18);
        $s5 -= self::mul($s12,  683901, 20);

        $carry0 = $s0 >> 21;
        $s1 += $carry0;
        $s0 -= $carry0 << 21;
        $carry1 = $s1 >> 21;
        $s2 += $carry1;
        $s1 -= $carry1 << 21;
        $carry2 = $s2 >> 21;
        $s3 += $carry2;
        $s2 -= $carry2 << 21;
        $carry3 = $s3 >> 21;
        $s4 += $carry3;
        $s3 -= $carry3 << 21;
        $carry4 = $s4 >> 21;
        $s5 += $carry4;
        $s4 -= $carry4 << 21;
        $carry5 = $s5 >> 21;
        $s6 += $carry5;
        $s5 -= $carry5 << 21;
        $carry6 = $s6 >> 21;
        $s7 += $carry6;
        $s6 -= $carry6 << 21;
        $carry7 = $s7 >> 21;
        $s8 += $carry7;
        $s7 -= $carry7 << 21;
        $carry8 = $s8 >> 21;
        $s9 += $carry8;
        $s8 -= $carry8 << 21;
        $carry9 = $s9 >> 21;
        $s10 += $carry9;
        $s9 -= $carry9 << 21;
        $carry10 = $s10 >> 21;
        $s11 += $carry10;
        $s10 -= $carry10 << 21;

        /**
         * @var array<int, int>
         */
        $arr = array(
            (int) (0xff & ($s0 >> 0)),
            (int) (0xff & ($s0 >> 8)),
            (int) (0xff & (($s0 >> 16) | $s1 << 5)),
            (int) (0xff & ($s1 >> 3)),
            (int) (0xff & ($s1 >> 11)),
            (int) (0xff & (($s1 >> 19) | $s2 << 2)),
            (int) (0xff & ($s2 >> 6)),
            (int) (0xff & (($s2 >> 14) | $s3 << 7)),
            (int) (0xff & ($s3 >> 1)),
            (int) (0xff & ($s3 >> 9)),
            (int) (0xff & (($s3 >> 17) | $s4 << 4)),
            (int) (0xff & ($s4 >> 4)),
            (int) (0xff & ($s4 >> 12)),
            (int) (0xff & (($s4 >> 20) | $s5 << 1)),
            (int) (0xff & ($s5 >> 7)),
            (int) (0xff & (($s5 >> 15) | $s6 << 6)),
            (int) (0xff & ($s6 >> 2)),
            (int) (0xff & ($s6 >> 10)),
            (int) (0xff & (($s6 >> 18) | $s7 << 3)),
            (int) (0xff & ($s7 >> 5)),
            (int) (0xff & ($s7 >> 13)),
            (int) (0xff & ($s8 >> 0)),
            (int) (0xff & ($s8 >> 8)),
            (int) (0xff & (($s8 >> 16) | $s9 << 5)),
            (int) (0xff & ($s9 >> 3)),
            (int) (0xff & ($s9 >> 11)),
            (int) (0xff & (($s9 >> 19) | $s10 << 2)),
            (int) (0xff & ($s10 >> 6)),
            (int) (0xff & (($s10 >> 14) | $s11 << 7)),
            (int) (0xff & ($s11 >> 1)),
            (int) (0xff & ($s11 >> 9)),
            0xff & ($s11 >> 17)
        );
        return self::intArrayToString($arr);
    }

    /**
     * @internal You should not use this directly from another application
     *
     * @param string $s
     * @return string
     * @throws TypeError
     */
    public static function sc_reduce($s)
    {
        $s0 = 2097151 & self::load_3(self::substr($s, 0, 3));
        $s1 = 2097151 & (self::load_4(self::substr($s, 2, 4)) >> 5);
        $s2 = 2097151 & (self::load_3(self::substr($s, 5, 3)) >> 2);
        $s3 = 2097151 & (self::load_4(self::substr($s, 7, 4)) >> 7);
        $s4 = 2097151 & (self::load_4(self::substr($s, 10, 4)) >> 4);
        $s5 = 2097151 & (self::load_3(self::substr($s, 13, 3)) >> 1);
        $s6 = 2097151 & (self::load_4(self::substr($s, 15, 4)) >> 6);
        $s7 = 2097151 & (self::load_3(self::substr($s, 18, 4)) >> 3);
        $s8 = 2097151 & self::load_3(self::substr($s, 21, 3));
        $s9 = 2097151 & (self::load_4(self::substr($s, 23, 4)) >> 5);
        $s10 = 2097151 & (self::load_3(self::substr($s, 26, 3)) >> 2);
        $s11 = 2097151 & (self::load_4(self::substr($s, 28, 4)) >> 7);
        $s12 = 2097151 & (self::load_4(self::substr($s, 31, 4)) >> 4);
        $s13 = 2097151 & (self::load_3(self::substr($s, 34, 3)) >> 1);
        $s14 = 2097151 & (self::load_4(self::substr($s, 36, 4)) >> 6);
        $s15 = 2097151 & (self::load_3(self::substr($s, 39, 4)) >> 3);
        $s16 = 2097151 & self::load_3(self::substr($s, 42, 3));
        $s17 = 2097151 & (self::load_4(self::substr($s, 44, 4)) >> 5);
        $s18 = 2097151 & (self::load_3(self::substr($s, 47, 3)) >> 2);
        $s19 = 2097151 & (self::load_4(self::substr($s, 49, 4)) >> 7);
        $s20 = 2097151 & (self::load_4(self::substr($s, 52, 4)) >> 4);
        $s21 = 2097151 & (self::load_3(self::substr($s, 55, 3)) >> 1);
        $s22 = 2097151 & (self::load_4(self::substr($s, 57, 4)) >> 6);
        $s23 = 0x1fffffff & (self::load_4(self::substr($s, 60, 4)) >> 3);

        $s11 += self::mul($s23,  666643, 20);
        $s12 += self::mul($s23,  470296, 19);
        $s13 += self::mul($s23,  654183, 20);
        $s14 -= self::mul($s23,  997805, 20);
        $s15 += self::mul($s23,  136657, 18);
        $s16 -= self::mul($s23,  683901, 20);

        $s10 += self::mul($s22,  666643, 20);
        $s11 += self::mul($s22,  470296, 19);
        $s12 += self::mul($s22,  654183, 20);
        $s13 -= self::mul($s22,  997805, 20);
        $s14 += self::mul($s22,  136657, 18);
        $s15 -= self::mul($s22,  683901, 20);

        $s9  += self::mul($s21,  666643, 20);
        $s10 += self::mul($s21,  470296, 19);
        $s11 += self::mul($s21,  654183, 20);
        $s12 -= self::mul($s21,  997805, 20);
        $s13 += self::mul($s21,  136657, 18);
        $s14 -= self::mul($s21,  683901, 20);

        $s8  += self::mul($s20,  666643, 20);
        $s9  += self::mul($s20,  470296, 19);
        $s10 += self::mul($s20,  654183, 20);
        $s11 -= self::mul($s20,  997805, 20);
        $s12 += self::mul($s20,  136657, 18);
        $s13 -= self::mul($s20,  683901, 20);

        $s7  += self::mul($s19,  666643, 20);
        $s8  += self::mul($s19,  470296, 19);
        $s9  += self::mul($s19,  654183, 20);
        $s10 -= self::mul($s19,  997805, 20);
        $s11 += self::mul($s19,  136657, 18);
        $s12 -= self::mul($s19,  683901, 20);

        $s6  += self::mul($s18,  666643, 20);
        $s7  += self::mul($s18,  470296, 19);
        $s8  += self::mul($s18,  654183, 20);
        $s9  -= self::mul($s18,  997805, 20);
        $s10 += self::mul($s18,  136657, 18);
        $s11 -= self::mul($s18,  683901, 20);

        $carry6 = ($s6 + (1 << 20)) >> 21;
        $s7 += $carry6;
        $s6 -= $carry6 << 21;
        $carry8 = ($s8 + (1 << 20)) >> 21;
        $s9 += $carry8;
        $s8 -= $carry8 << 21;
        $carry10 = ($s10 + (1 << 20)) >> 21;
        $s11 += $carry10;
        $s10 -= $carry10 << 21;
        $carry12 = ($s12 + (1 << 20)) >> 21;
        $s13 += $carry12;
        $s12 -= $carry12 << 21;
        $carry14 = ($s14 + (1 << 20)) >> 21;
        $s15 += $carry14;
        $s14 -= $carry14 << 21;
        $carry16 = ($s16 + (1 << 20)) >> 21;
        $s17 += $carry16;
        $s16 -= $carry16 << 21;

        $carry7 = ($s7 + (1 << 20)) >> 21;
        $s8 += $carry7;
        $s7 -= $carry7 << 21;
        $carry9 = ($s9 + (1 << 20)) >> 21;
        $s10 += $carry9;
        $s9 -= $carry9 << 21;
        $carry11 = ($s11 + (1 << 20)) >> 21;
        $s12 += $carry11;
        $s11 -= $carry11 << 21;
        $carry13 = ($s13 + (1 << 20)) >> 21;
        $s14 += $carry13;
        $s13 -= $carry13 << 21;
        $carry15 = ($s15 + (1 << 20)) >> 21;
        $s16 += $carry15;
        $s15 -= $carry15 << 21;

        $s5  += self::mul($s17,  666643, 20);
        $s6  += self::mul($s17,  470296, 19);
        $s7  += self::mul($s17,  654183, 20);
        $s8  -= self::mul($s17,  997805, 20);
        $s9  += self::mul($s17,  136657, 18);
        $s10 -= self::mul($s17,  683901, 20);

        $s4 += self::mul($s16,  666643, 20);
        $s5 += self::mul($s16,  470296, 19);
        $s6 += self::mul($s16,  654183, 20);
        $s7 -= self::mul($s16,  997805, 20);
        $s8 += self::mul($s16,  136657, 18);
        $s9 -= self::mul($s16,  683901, 20);

        $s3 += self::mul($s15,  666643, 20);
        $s4 += self::mul($s15,  470296, 19);
        $s5 += self::mul($s15,  654183, 20);
        $s6 -= self::mul($s15,  997805, 20);
        $s7 += self::mul($s15,  136657, 18);
        $s8 -= self::mul($s15,  683901, 20);

        $s2 += self::mul($s14,  666643, 20);
        $s3 += self::mul($s14,  470296, 19);
        $s4 += self::mul($s14,  654183, 20);
        $s5 -= self::mul($s14,  997805, 20);
        $s6 += self::mul($s14,  136657, 18);
        $s7 -= self::mul($s14,  683901, 20);

        $s1 += self::mul($s13,  666643, 20);
        $s2 += self::mul($s13,  470296, 19);
        $s3 += self::mul($s13,  654183, 20);
        $s4 -= self::mul($s13,  997805, 20);
        $s5 += self::mul($s13,  136657, 18);
        $s6 -= self::mul($s13,  683901, 20);

        $s0 += self::mul($s12,  666643, 20);
        $s1 += self::mul($s12,  470296, 19);
        $s2 += self::mul($s12,  654183, 20);
        $s3 -= self::mul($s12,  997805, 20);
        $s4 += self::mul($s12,  136657, 18);
        $s5 -= self::mul($s12,  683901, 20);
        $s12 = 0;

        $carry0 = ($s0 + (1 << 20)) >> 21;
        $s1 += $carry0;
        $s0 -= $carry0 << 21;
        $carry2 = ($s2 + (1 << 20)) >> 21;
        $s3 += $carry2;
        $s2 -= $carry2 << 21;
        $carry4 = ($s4 + (1 << 20)) >> 21;
        $s5 += $carry4;
        $s4 -= $carry4 << 21;
        $carry6 = ($s6 + (1 << 20)) >> 21;
        $s7 += $carry6;
        $s6 -= $carry6 << 21;
        $carry8 = ($s8 + (1 << 20)) >> 21;
        $s9 += $carry8;
        $s8 -= $carry8 << 21;
        $carry10 = ($s10 + (1 << 20)) >> 21;
        $s11 += $carry10;
        $s10 -= $carry10 << 21;

        $carry1 = ($s1 + (1 << 20)) >> 21;
        $s2 += $carry1;
        $s1 -= $carry1 << 21;
        $carry3 = ($s3 + (1 << 20)) >> 21;
        $s4 += $carry3;
        $s3 -= $carry3 << 21;
        $carry5 = ($s5 + (1 << 20)) >> 21;
        $s6 += $carry5;
        $s5 -= $carry5 << 21;
        $carry7 = ($s7 + (1 << 20)) >> 21;
        $s8 += $carry7;
        $s7 -= $carry7 << 21;
        $carry9 = ($s9 + (1 << 20)) >> 21;
        $s10 += $carry9;
        $s9 -= $carry9 << 21;
        $carry11 = ($s11 + (1 << 20)) >> 21;
        $s12 += $carry11;
        $s11 -= $carry11 << 21;

        $s0 += self::mul($s12,  666643, 20);
        $s1 += self::mul($s12,  470296, 19);
        $s2 += self::mul($s12,  654183, 20);
        $s3 -= self::mul($s12,  997805, 20);
        $s4 += self::mul($s12,  136657, 18);
        $s5 -= self::mul($s12,  683901, 20);
        $s12 = 0;

        $carry0 = $s0 >> 21;
        $s1 += $carry0;
        $s0 -= $carry0 << 21;
        $carry1 = $s1 >> 21;
        $s2 += $carry1;
        $s1 -= $carry1 << 21;
        $carry2 = $s2 >> 21;
        $s3 += $carry2;
        $s2 -= $carry2 << 21;
        $carry3 = $s3 >> 21;
        $s4 += $carry3;
        $s3 -= $carry3 << 21;
        $carry4 = $s4 >> 21;
        $s5 += $carry4;
        $s4 -= $carry4 << 21;
        $carry5 = $s5 >> 21;
        $s6 += $carry5;
        $s5 -= $carry5 << 21;
        $carry6 = $s6 >> 21;
        $s7 += $carry6;
        $s6 -= $carry6 << 21;
        $carry7 = $s7 >> 21;
        $s8 += $carry7;
        $s7 -= $carry7 << 21;
        $carry8 = $s8 >> 21;
        $s9 += $carry8;
        $s8 -= $carry8 << 21;
        $carry9 = $s9 >> 21;
        $s10 += $carry9;
        $s9 -= $carry9 << 21;
        $carry10 = $s10 >> 21;
        $s11 += $carry10;
        $s10 -= $carry10 << 21;
        $carry11 = $s11 >> 21;
        $s12 += $carry11;
        $s11 -= $carry11 << 21;

        $s0 += self::mul($s12,  666643, 20);
        $s1 += self::mul($s12,  470296, 19);
        $s2 += self::mul($s12,  654183, 20);
        $s3 -= self::mul($s12,  997805, 20);
        $s4 += self::mul($s12,  136657, 18);
        $s5 -= self::mul($s12,  683901, 20);

        $carry0 = $s0 >> 21;
        $s1 += $carry0;
        $s0 -= $carry0 << 21;
        $carry1 = $s1 >> 21;
        $s2 += $carry1;
        $s1 -= $carry1 << 21;
        $carry2 = $s2 >> 21;
        $s3 += $carry2;
        $s2 -= $carry2 << 21;
        $carry3 = $s3 >> 21;
        $s4 += $carry3;
        $s3 -= $carry3 << 21;
        $carry4 = $s4 >> 21;
        $s5 += $carry4;
        $s4 -= $carry4 << 21;
        $carry5 = $s5 >> 21;
        $s6 += $carry5;
        $s5 -= $carry5 << 21;
        $carry6 = $s6 >> 21;
        $s7 += $carry6;
        $s6 -= $carry6 << 21;
        $carry7 = $s7 >> 21;
        $s8 += $carry7;
        $s7 -= $carry7 << 21;
        $carry8 = $s8 >> 21;
        $s9 += $carry8;
        $s8 -= $carry8 << 21;
        $carry9 = $s9 >> 21;
        $s10 += $carry9;
        $s9 -= $carry9 << 21;
        $carry10 = $s10 >> 21;
        $s11 += $carry10;
        $s10 -= $carry10 << 21;

        /**
         * @var array<int, int>
         */
        $arr = array(
            (int) ($s0 >> 0),
            (int) ($s0 >> 8),
            (int) (($s0 >> 16) | $s1 << 5),
            (int) ($s1 >> 3),
            (int) ($s1 >> 11),
            (int) (($s1 >> 19) | $s2 << 2),
            (int) ($s2 >> 6),
            (int) (($s2 >> 14) | $s3 << 7),
            (int) ($s3 >> 1),
            (int) ($s3 >> 9),
            (int) (($s3 >> 17) | $s4 << 4),
            (int) ($s4 >> 4),
            (int) ($s4 >> 12),
            (int) (($s4 >> 20) | $s5 << 1),
            (int) ($s5 >> 7),
            (int) (($s5 >> 15) | $s6 << 6),
            (int) ($s6 >> 2),
            (int) ($s6 >> 10),
            (int) (($s6 >> 18) | $s7 << 3),
            (int) ($s7 >> 5),
            (int) ($s7 >> 13),
            (int) ($s8 >> 0),
            (int) ($s8 >> 8),
            (int) (($s8 >> 16) | $s9 << 5),
            (int) ($s9 >> 3),
            (int) ($s9 >> 11),
            (int) (($s9 >> 19) | $s10 << 2),
            (int) ($s10 >> 6),
            (int) (($s10 >> 14) | $s11 << 7),
            (int) ($s11 >> 1),
            (int) ($s11 >> 9),
            (int) $s11 >> 17
        );
        return self::intArrayToString($arr);
    }

    /**
     * multiply by the order of the main subgroup l = 2^252+27742317777372353535851937790883648493
     *
     * @param ParagonIE_Sodium_Core_Curve25519_Ge_P3 $A
     * @return ParagonIE_Sodium_Core_Curve25519_Ge_P3
     */
    public static function ge_mul_l(ParagonIE_Sodium_Core_Curve25519_Ge_P3 $A)
    {
        $aslide = array(
            13, 0, 0, 0, 0, -1, 0, 0, 0, 0, -11, 0, 0, 0, 0, 0, 0, -5, 0, 0, 0,
            0, 0, 0, -3, 0, 0, 0, 0, -13, 0, 0, 0, 0, 7, 0, 0, 0, 0, 0, 3, 0,
            0, 0, 0, -13, 0, 0, 0, 0, 5, 0, 0, 0, 0, 0, 0, 0, 0, 11, 0, 0, 0,
            0, 0, 11, 0, 0, 0, 0, -13, 0, 0, 0, 0, 0, 0, -3, 0, 0, 0, 0, 0, -1,
            0, 0, 0, 0, 3, 0, 0, 0, 0, -11, 0, 0, 0, 0, 0, 0, 0, 15, 0, 0, 0,
            0, 0, -1, 0, 0, 0, 0, -1, 0, 0, 0, 0, 7, 0, 0, 0, 0, 5, 0, 0, 0, 0,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1
        );

        /** @var array<int, ParagonIE_Sodium_Core_Curve25519_Ge_Cached> $Ai size 8 */
        $Ai = array();

        # ge_p3_to_cached(&Ai[0], A);
        $Ai[0] = self::ge_p3_to_cached($A);
        # ge_p3_dbl(&t, A);
        $t = self::ge_p3_dbl($A);
        # ge_p1p1_to_p3(&A2, &t);
        $A2 = self::ge_p1p1_to_p3($t);

        for ($i = 1; $i < 8; ++$i) {
            # ge_add(&t, &A2, &Ai[0]);
            $t = self::ge_add($A2, $Ai[$i - 1]);
            # ge_p1p1_to_p3(&u, &t);
            $u = self::ge_p1p1_to_p3($t);
            # ge_p3_to_cached(&Ai[i], &u);
            $Ai[$i] = self::ge_p3_to_cached($u);
        }

        $r = self::ge_p3_0();
        for ($i = 252; $i >= 0; --$i) {
            $t = self::ge_p3_dbl($r);
            if ($aslide[$i] > 0) {
                # ge_p1p1_to_p3(&u, &t);
                $u = self::ge_p1p1_to_p3($t);
                # ge_add(&t, &u, &Ai[aslide[i] / 2]);
                $t = self::ge_add($u, $Ai[(int)($aslide[$i] / 2)]);
            } elseif ($aslide[$i] < 0) {
                # ge_p1p1_to_p3(&u, &t);
                $u = self::ge_p1p1_to_p3($t);
                # ge_sub(&t, &u, &Ai[(-aslide[i]) / 2]);
                $t = self::ge_sub($u, $Ai[(int)(-$aslide[$i] / 2)]);
            }
        }

        # ge_p1p1_to_p3(r, &t);
        return self::ge_p1p1_to_p3($t);
    }

    /**
     * @param string $a
     * @param string $b
     * @return string
     */
    public static function sc25519_mul($a, $b)
    {
        //    int64_t a0  = 2097151 & load_3(a);
        //    int64_t a1  = 2097151 & (load_4(a + 2) >> 5);
        //    int64_t a2  = 2097151 & (load_3(a + 5) >> 2);
        //    int64_t a3  = 2097151 & (load_4(a + 7) >> 7);
        //    int64_t a4  = 2097151 & (load_4(a + 10) >> 4);
        //    int64_t a5  = 2097151 & (load_3(a + 13) >> 1);
        //    int64_t a6  = 2097151 & (load_4(a + 15) >> 6);
        //    int64_t a7  = 2097151 & (load_3(a + 18) >> 3);
        //    int64_t a8  = 2097151 & load_3(a + 21);
        //    int64_t a9  = 2097151 & (load_4(a + 23) >> 5);
        //    int64_t a10 = 2097151 & (load_3(a + 26) >> 2);
        //    int64_t a11 = (load_4(a + 28) >> 7);
        $a0  = 2097151 &  self::load_3(self::substr($a, 0, 3));
        $a1  = 2097151 & (self::load_4(self::substr($a, 2, 4)) >> 5);
        $a2  = 2097151 & (self::load_3(self::substr($a, 5, 3)) >> 2);
        $a3  = 2097151 & (self::load_4(self::substr($a, 7, 4)) >> 7);
        $a4  = 2097151 & (self::load_4(self::substr($a, 10, 4)) >> 4);
        $a5  = 2097151 & (self::load_3(self::substr($a, 13, 3)) >> 1);
        $a6  = 2097151 & (self::load_4(self::substr($a, 15, 4)) >> 6);
        $a7  = 2097151 & (self::load_3(self::substr($a, 18, 3)) >> 3);
        $a8  = 2097151 &  self::load_3(self::substr($a, 21, 3));
        $a9  = 2097151 & (self::load_4(self::substr($a, 23, 4)) >> 5);
        $a10 = 2097151 & (self::load_3(self::substr($a, 26, 3)) >> 2);
        $a11 = (self::load_4(self::substr($a, 28, 4)) >> 7);

        //    int64_t b0  = 2097151 & load_3(b);
        //    int64_t b1  = 2097151 & (load_4(b + 2) >> 5);
        //    int64_t b2  = 2097151 & (load_3(b + 5) >> 2);
        //    int64_t b3  = 2097151 & (load_4(b + 7) >> 7);
        //    int64_t b4  = 2097151 & (load_4(b + 10) >> 4);
        //    int64_t b5  = 2097151 & (load_3(b + 13) >> 1);
        //    int64_t b6  = 2097151 & (load_4(b + 15) >> 6);
        //    int64_t b7  = 2097151 & (load_3(b + 18) >> 3);
        //    int64_t b8  = 2097151 & load_3(b + 21);
        //    int64_t b9  = 2097151 & (load_4(b + 23) >> 5);
        //    int64_t b10 = 2097151 & (load_3(b + 26) >> 2);
        //    int64_t b11 = (load_4(b + 28) >> 7);
        $b0  = 2097151 &  self::load_3(self::substr($b, 0, 3));
        $b1  = 2097151 & (self::load_4(self::substr($b, 2, 4)) >> 5);
        $b2  = 2097151 & (self::load_3(self::substr($b, 5, 3)) >> 2);
        $b3  = 2097151 & (self::load_4(self::substr($b, 7, 4)) >> 7);
        $b4  = 2097151 & (self::load_4(self::substr($b, 10, 4)) >> 4);
        $b5  = 2097151 & (self::load_3(self::substr($b, 13, 3)) >> 1);
        $b6  = 2097151 & (self::load_4(self::substr($b, 15, 4)) >> 6);
        $b7  = 2097151 & (self::load_3(self::substr($b, 18, 3)) >> 3);
        $b8  = 2097151 &  self::load_3(self::substr($b, 21, 3));
        $b9  = 2097151 & (self::load_4(self::substr($b, 23, 4)) >> 5);
        $b10 = 2097151 & (self::load_3(self::substr($b, 26, 3)) >> 2);
        $b11 = (self::load_4(self::substr($b, 28, 4)) >> 7);

        //    s0 = a0 * b0;
        //    s1 = a0 * b1 + a1 * b0;
        //    s2 = a0 * b2 + a1 * b1 + a2 * b0;
        //    s3 = a0 * b3 + a1 * b2 + a2 * b1 + a3 * b0;
        //    s4 = a0 * b4 + a1 * b3 + a2 * b2 + a3 * b1 + a4 * b0;
        //    s5 = a0 * b5 + a1 * b4 + a2 * b3 + a3 * b2 + a4 * b1 + a5 * b0;
        //    s6 = a0 * b6 + a1 * b5 + a2 * b4 + a3 * b3 + a4 * b2 + a5 * b1 + a6 * b0;
        //    s7 = a0 * b7 + a1 * b6 + a2 * b5 + a3 * b4 + a4 * b3 + a5 * b2 +
        //        a6 * b1 + a7 * b0;
        //    s8 = a0 * b8 + a1 * b7 + a2 * b6 + a3 * b5 + a4 * b4 + a5 * b3 +
        //        a6 * b2 + a7 * b1 + a8 * b0;
        //    s9 = a0 * b9 + a1 * b8 + a2 * b7 + a3 * b6 + a4 * b5 + a5 * b4 +
        //        a6 * b3 + a7 * b2 + a8 * b1 + a9 * b0;
        //    s10 = a0 * b10 + a1 * b9 + a2 * b8 + a3 * b7 + a4 * b6 + a5 * b5 +
        //        a6 * b4 + a7 * b3 + a8 * b2 + a9 * b1 + a10 * b0;
        //    s11 = a0 * b11 + a1 * b10 + a2 * b9 + a3 * b8 + a4 * b7 + a5 * b6 +
        //        a6 * b5 + a7 * b4 + a8 * b3 + a9 * b2 + a10 * b1 + a11 * b0;
        //    s12 = a1 * b11 + a2 * b10 + a3 * b9 + a4 * b8 + a5 * b7 + a6 * b6 +
        //        a7 * b5 + a8 * b4 + a9 * b3 + a10 * b2 + a11 * b1;
        //    s13 = a2 * b11 + a3 * b10 + a4 * b9 + a5 * b8 + a6 * b7 + a7 * b6 +
        //        a8 * b5 + a9 * b4 + a10 * b3 + a11 * b2;
        //    s14 = a3 * b11 + a4 * b10 + a5 * b9 + a6 * b8 + a7 * b7 + a8 * b6 +
        //        a9 * b5 + a10 * b4 + a11 * b3;
        //    s15 = a4 * b11 + a5 * b10 + a6 * b9 + a7 * b8 + a8 * b7 + a9 * b6 +
        //        a10 * b5 + a11 * b4;
        //    s16 =
        //        a5 * b11 + a6 * b10 + a7 * b9 + a8 * b8 + a9 * b7 + a10 * b6 + a11 * b5;
        //    s17 = a6 * b11 + a7 * b10 + a8 * b9 + a9 * b8 + a10 * b7 + a11 * b6;
        //    s18 = a7 * b11 + a8 * b10 + a9 * b9 + a10 * b8 + a11 * b7;
        //    s19 = a8 * b11 + a9 * b10 + a10 * b9 + a11 * b8;
        //    s20 = a9 * b11 + a10 * b10 + a11 * b9;
        //    s21 = a10 * b11 + a11 * b10;
        //    s22 = a11 * b11;
        //    s23 = 0;
        $s0 = self::mul($a0, $b0, 22);
        $s1 = self::mul($a0, $b1, 22) + self::mul($a1, $b0, 22);
        $s2 = self::mul($a0, $b2, 22) + self::mul($a1, $b1, 22) + self::mul($a2, $b0, 22);
        $s3 = self::mul($a0, $b3, 22) + self::mul($a1, $b2, 22) + self::mul($a2, $b1, 22) + self::mul($a3, $b0, 22);
        $s4 = self::mul($a0, $b4, 22) + self::mul($a1, $b3, 22) + self::mul($a2, $b2, 22) + self::mul($a3, $b1, 22) +
            self::mul($a4, $b0, 22);
        $s5 = self::mul($a0, $b5, 22) + self::mul($a1, $b4, 22) + self::mul($a2, $b3, 22) + self::mul($a3, $b2, 22) +
            self::mul($a4, $b1, 22) + self::mul($a5, $b0, 22);
        $s6 = self::mul($a0, $b6, 22) + self::mul($a1, $b5, 22) + self::mul($a2, $b4, 22) + self::mul($a3, $b3, 22) +
            self::mul($a4, $b2, 22) + self::mul($a5, $b1, 22) + self::mul($a6, $b0, 22);
        $s7 = self::mul($a0, $b7, 22) + self::mul($a1, $b6, 22) + self::mul($a2, $b5, 22) + self::mul($a3, $b4, 22) +
            self::mul($a4, $b3, 22) + self::mul($a5, $b2, 22) + self::mul($a6, $b1, 22) + self::mul($a7, $b0, 22);
        $s8 = self::mul($a0, $b8, 22) + self::mul($a1, $b7, 22) + self::mul($a2, $b6, 22) + self::mul($a3, $b5, 22) +
            self::mul($a4, $b4, 22) + self::mul($a5, $b3, 22) + self::mul($a6, $b2, 22) + self::mul($a7, $b1, 22) +
            self::mul($a8, $b0, 22);
        $s9 = self::mul($a0, $b9, 22) + self::mul($a1, $b8, 22) + self::mul($a2, $b7, 22) + self::mul($a3, $b6, 22) +
            self::mul($a4, $b5, 22) + self::mul($a5, $b4, 22) + self::mul($a6, $b3, 22) + self::mul($a7, $b2, 22) +
            self::mul($a8, $b1, 22) + self::mul($a9, $b0, 22);
        $s10 = self::mul($a0, $b10, 22) + self::mul($a1, $b9, 22) + self::mul($a2, $b8, 22) + self::mul($a3, $b7, 22) +
            self::mul($a4, $b6, 22) + self::mul($a5, $b5, 22) + self::mul($a6, $b4, 22) + self::mul($a7, $b3, 22) +
            self::mul($a8, $b2, 22) + self::mul($a9, $b1, 22) + self::mul($a10, $b0, 22);
        $s11 = self::mul($a0, $b11, 22) + self::mul($a1, $b10, 22) + self::mul($a2, $b9, 22) + self::mul($a3, $b8, 22) +
            self::mul($a4, $b7, 22) + self::mul($a5, $b6, 22) + self::mul($a6, $b5, 22) + self::mul($a7, $b4, 22) +
            self::mul($a8, $b3, 22) + self::mul($a9, $b2, 22) + self::mul($a10, $b1, 22) + self::mul($a11, $b0, 22);
        $s12 = self::mul($a1, $b11, 22) + self::mul($a2, $b10, 22) + self::mul($a3, $b9, 22) + self::mul($a4, $b8, 22) +
            self::mul($a5, $b7, 22) + self::mul($a6, $b6, 22) + self::mul($a7, $b5, 22) + self::mul($a8, $b4, 22) +
            self::mul($a9, $b3, 22) + self::mul($a10, $b2, 22) + self::mul($a11, $b1, 22);
        $s13 = self::mul($a2, $b11, 22) + self::mul($a3, $b10, 22) + self::mul($a4, $b9, 22) + self::mul($a5, $b8, 22) +
            self::mul($a6, $b7, 22) + self::mul($a7, $b6, 22) + self::mul($a8, $b5, 22) + self::mul($a9, $b4, 22) +
            self::mul($a10, $b3, 22) + self::mul($a11, $b2, 22);
        $s14 = self::mul($a3, $b11, 22) + self::mul($a4, $b10, 22) + self::mul($a5, $b9, 22) + self::mul($a6, $b8, 22) +
            self::mul($a7, $b7, 22) + self::mul($a8, $b6, 22) + self::mul($a9, $b5, 22) + self::mul($a10, $b4, 22) +
            self::mul($a11, $b3, 22);
        $s15 = self::mul($a4, $b11, 22) + self::mul($a5, $b10, 22) + self::mul($a6, $b9, 22) + self::mul($a7, $b8, 22) +
            self::mul($a8, $b7, 22) + self::mul($a9, $b6, 22) + self::mul($a10, $b5, 22) + self::mul($a11, $b4, 22);
        $s16 =
            self::mul($a5, $b11, 22) + self::mul($a6, $b10, 22) + self::mul($a7, $b9, 22) + self::mul($a8, $b8, 22) +
            self::mul($a9, $b7, 22) + self::mul($a10, $b6, 22) + self::mul($a11, $b5, 22);
        $s17 = self::mul($a6, $b11, 22) + self::mul($a7, $b10, 22) + self::mul($a8, $b9, 22) + self::mul($a9, $b8, 22) +
            self::mul($a10, $b7, 22) + self::mul($a11, $b6, 22);
        $s18 = self::mul($a7, $b11, 22) + self::mul($a8, $b10, 22) + self::mul($a9, $b9, 22) + self::mul($a10, $b8, 22)
            + self::mul($a11, $b7, 22);
        $s19 = self::mul($a8, $b11, 22) + self::mul($a9, $b10, 22) + self::mul($a10, $b9, 22) +
            self::mul($a11, $b8, 22);
        $s20 = self::mul($a9, $b11, 22) + self::mul($a10, $b10, 22) + self::mul($a11, $b9, 22);
        $s21 = self::mul($a10, $b11, 22) + self::mul($a11, $b10, 22);
        $s22 = self::mul($a11, $b11, 22);
        $s23 = 0;

        //    carry0 = (s0 + (int64_t) (1L << 20)) >> 21;
        //    s1 += carry0;
        //    s0 -= carry0 * ((uint64_t) 1L << 21);
        $carry0 = ($s0 + (1 << 20)) >> 21;
        $s1 += $carry0;
        $s0 -= $carry0 << 21;
        //    carry2 = (s2 + (int64_t) (1L << 20)) >> 21;
        //    s3 += carry2;
        //    s2 -= carry2 * ((uint64_t) 1L << 21);
        $carry2 = ($s2 + (1 << 20)) >> 21;
        $s3 += $carry2;
        $s2 -= $carry2 << 21;
        //    carry4 = (s4 + (int64_t) (1L << 20)) >> 21;
        //    s5 += carry4;
        //    s4 -= carry4 * ((uint64_t) 1L << 21);
        $carry4 = ($s4 + (1 << 20)) >> 21;
        $s5 += $carry4;
        $s4 -= $carry4 << 21;
        //    carry6 = (s6 + (int64_t) (1L << 20)) >> 21;
        //    s7 += carry6;
        //    s6 -= carry6 * ((uint64_t) 1L << 21);
        $carry6 = ($s6 + (1 << 20)) >> 21;
        $s7 += $carry6;
        $s6 -= $carry6 << 21;
        //    carry8 = (s8 + (int64_t) (1L << 20)) >> 21;
        //    s9 += carry8;
        //    s8 -= carry8 * ((uint64_t) 1L << 21);
        $carry8 = ($s8 + (1 << 20)) >> 21;
        $s9 += $carry8;
        $s8 -= $carry8 << 21;
        //    carry10 = (s10 + (int64_t) (1L << 20)) >> 21;
        //    s11 += carry10;
        //    s10 -= carry10 * ((uint64_t) 1L << 21);
        $carry10 = ($s10 + (1 << 20)) >> 21;
        $s11 += $carry10;
        $s10 -= $carry10 << 21;
        //    carry12 = (s12 + (int64_t) (1L << 20)) >> 21;
        //    s13 += carry12;
        //    s12 -= carry12 * ((uint64_t) 1L << 21);
        $carry12 = ($s12 + (1 << 20)) >> 21;
        $s13 += $carry12;
        $s12 -= $carry12 << 21;
        //    carry14 = (s14 + (int64_t) (1L << 20)) >> 21;
        //    s15 += carry14;
        //    s14 -= carry14 * ((uint64_t) 1L << 21);
        $carry14 = ($s14 + (1 << 20)) >> 21;
        $s15 += $carry14;
        $s14 -= $carry14 << 21;
        //    carry16 = (s16 + (int64_t) (1L << 20)) >> 21;
        //    s17 += carry16;
        //    s16 -= carry16 * ((uint64_t) 1L << 21);
        $carry16 = ($s16 + (1 << 20)) >> 21;
        $s17 += $carry16;
        $s16 -= $carry16 << 21;
        //    carry18 = (s18 + (int64_t) (1L << 20)) >> 21;
        //    s19 += carry18;
        //    s18 -= carry18 * ((uint64_t) 1L << 21);
        $carry18 = ($s18 + (1 << 20)) >> 21;
        $s19 += $carry18;
        $s18 -= $carry18 << 21;
        //    carry20 = (s20 + (int64_t) (1L << 20)) >> 21;
        //    s21 += carry20;
        //    s20 -= carry20 * ((uint64_t) 1L << 21);
        $carry20 = ($s20 + (1 << 20)) >> 21;
        $s21 += $carry20;
        $s20 -= $carry20 << 21;
        //    carry22 = (s22 + (int64_t) (1L << 20)) >> 21;
        //    s23 += carry22;
        //    s22 -= carry22 * ((uint64_t) 1L << 21);
        $carry22 = ($s22 + (1 << 20)) >> 21;
        $s23 += $carry22;
        $s22 -= $carry22 << 21;

        //    carry1 = (s1 + (int64_t) (1L << 20)) >> 21;
        //    s2 += carry1;
        //    s1 -= carry1 * ((uint64_t) 1L << 21);
        $carry1 = ($s1 + (1 << 20)) >> 21;
        $s2 += $carry1;
        $s1 -= $carry1 << 21;
        //    carry3 = (s3 + (int64_t) (1L << 20)) >> 21;
        //    s4 += carry3;
        //    s3 -= carry3 * ((uint64_t) 1L << 21);
        $carry3 = ($s3 + (1 << 20)) >> 21;
        $s4 += $carry3;
        $s3 -= $carry3 << 21;
        //    carry5 = (s5 + (int64_t) (1L << 20)) >> 21;
        //    s6 += carry5;
        //    s5 -= carry5 * ((uint64_t) 1L << 21);
        $carry5 = ($s5 + (1 << 20)) >> 21;
        $s6 += $carry5;
        $s5 -= $carry5 << 21;
        //    carry7 = (s7 + (int64_t) (1L << 20)) >> 21;
        //    s8 += carry7;
        //    s7 -= carry7 * ((uint64_t) 1L << 21);
        $carry7 = ($s7 + (1 << 20)) >> 21;
        $s8 += $carry7;
        $s7 -= $carry7 << 21;
        //    carry9 = (s9 + (int64_t) (1L << 20)) >> 21;
        //    s10 += carry9;
        //    s9 -= carry9 * ((uint64_t) 1L << 21);
        $carry9 = ($s9 + (1 << 20)) >> 21;
        $s10 += $carry9;
        $s9 -= $carry9 << 21;
        //    carry11 = (s11 + (int64_t) (1L << 20)) >> 21;
        //    s12 += carry11;
        //    s11 -= carry11 * ((uint64_t) 1L << 21);
        $carry11 = ($s11 + (1 << 20)) >> 21;
        $s12 += $carry11;
        $s11 -= $carry11 << 21;
        //    carry13 = (s13 + (int64_t) (1L << 20)) >> 21;
        //    s14 += carry13;
        //    s13 -= carry13 * ((uint64_t) 1L << 21);
        $carry13 = ($s13 + (1 << 20)) >> 21;
        $s14 += $carry13;
        $s13 -= $carry13 << 21;
        //    carry15 = (s15 + (int64_t) (1L << 20)) >> 21;
        //    s16 += carry15;
        //    s15 -= carry15 * ((uint64_t) 1L << 21);
        $carry15 = ($s15 + (1 << 20)) >> 21;
        $s16 += $carry15;
        $s15 -= $carry15 << 21;
        //    carry17 = (s17 + (int64_t) (1L << 20)) >> 21;
        //    s18 += carry17;
        //    s17 -= carry17 * ((uint64_t) 1L << 21);
        $carry17 = ($s17 + (1 << 20)) >> 21;
        $s18 += $carry17;
        $s17 -= $carry17 << 21;
        //    carry19 = (s19 + (int64_t) (1L << 20)) >> 21;
        //    s20 += carry19;
        //    s19 -= carry19 * ((uint64_t) 1L << 21);
        $carry19 = ($s19 + (1 << 20)) >> 21;
        $s20 += $carry19;
        $s19 -= $carry19 << 21;
        //    carry21 = (s21 + (int64_t) (1L << 20)) >> 21;
        //    s22 += carry21;
        //    s21 -= carry21 * ((uint64_t) 1L << 21);
        $carry21 = ($s21 + (1 << 20)) >> 21;
        $s22 += $carry21;
        $s21 -= $carry21 << 21;

        //    s11 += s23 * 666643;
        //    s12 += s23 * 470296;
        //    s13 += s23 * 654183;
        //    s14 -= s23 * 997805;
        //    s15 += s23 * 136657;
        //    s16 -= s23 * 683901;
        $s11 += self::mul($s23, 666643, 20);
        $s12 += self::mul($s23, 470296, 19);
        $s13 += self::mul($s23, 654183, 20);
        $s14 -= self::mul($s23, 997805, 20);
        $s15 += self::mul($s23, 136657, 18);
        $s16 -= self::mul($s23, 683901, 20);

        //    s10 += s22 * 666643;
        //    s11 += s22 * 470296;
        //    s12 += s22 * 654183;
        //    s13 -= s22 * 997805;
        //    s14 += s22 * 136657;
        //    s15 -= s22 * 683901;
        $s10 += self::mul($s22, 666643, 20);
        $s11 += self::mul($s22, 470296, 19);
        $s12 += self::mul($s22, 654183, 20);
        $s13 -= self::mul($s22, 997805, 20);
        $s14 += self::mul($s22, 136657, 18);
        $s15 -= self::mul($s22, 683901, 20);

        //    s9 += s21 * 666643;
        //    s10 += s21 * 470296;
        //    s11 += s21 * 654183;
        //    s12 -= s21 * 997805;
        //    s13 += s21 * 136657;
        //    s14 -= s21 * 683901;
        $s9 += self::mul($s21, 666643, 20);
        $s10 += self::mul($s21, 470296, 19);
        $s11 += self::mul($s21, 654183, 20);
        $s12 -= self::mul($s21, 997805, 20);
        $s13 += self::mul($s21, 136657, 18);
        $s14 -= self::mul($s21, 683901, 20);

        //    s8 += s20 * 666643;
        //    s9 += s20 * 470296;
        //    s10 += s20 * 654183;
        //    s11 -= s20 * 997805;
        //    s12 += s20 * 136657;
        //    s13 -= s20 * 683901;
        $s8 += self::mul($s20, 666643, 20);
        $s9 += self::mul($s20, 470296, 19);
        $s10 += self::mul($s20, 654183, 20);
        $s11 -= self::mul($s20, 997805, 20);
        $s12 += self::mul($s20, 136657, 18);
        $s13 -= self::mul($s20, 683901, 20);

        //    s7 += s19 * 666643;
        //    s8 += s19 * 470296;
        //    s9 += s19 * 654183;
        //    s10 -= s19 * 997805;
        //    s11 += s19 * 136657;
        //    s12 -= s19 * 683901;
        $s7 += self::mul($s19, 666643, 20);
        $s8 += self::mul($s19, 470296, 19);
        $s9 += self::mul($s19, 654183, 20);
        $s10 -= self::mul($s19, 997805, 20);
        $s11 += self::mul($s19, 136657, 18);
        $s12 -= self::mul($s19, 683901, 20);

        //    s6 += s18 * 666643;
        //    s7 += s18 * 470296;
        //    s8 += s18 * 654183;
        //    s9 -= s18 * 997805;
        //    s10 += s18 * 136657;
        //    s11 -= s18 * 683901;
        $s6 += self::mul($s18, 666643, 20);
        $s7 += self::mul($s18, 470296, 19);
        $s8 += self::mul($s18, 654183, 20);
        $s9 -= self::mul($s18, 997805, 20);
        $s10 += self::mul($s18, 136657, 18);
        $s11 -= self::mul($s18, 683901, 20);

        //    carry6 = (s6 + (int64_t) (1L << 20)) >> 21;
        //    s7 += carry6;
        //    s6 -= carry6 * ((uint64_t) 1L << 21);
        $carry6 = ($s6 + (1 << 20)) >> 21;
        $s7 += $carry6;
        $s6 -= $carry6 << 21;
        //    carry8 = (s8 + (int64_t) (1L << 20)) >> 21;
        //    s9 += carry8;
        //    s8 -= carry8 * ((uint64_t) 1L << 21);
        $carry8 = ($s8 + (1 << 20)) >> 21;
        $s9 += $carry8;
        $s8 -= $carry8 << 21;
        //    carry10 = (s10 + (int64_t) (1L << 20)) >> 21;
        //    s11 += carry10;
        //    s10 -= carry10 * ((uint64_t) 1L << 21);
        $carry10 = ($s10 + (1 << 20)) >> 21;
        $s11 += $carry10;
        $s10 -= $carry10 << 21;
        //    carry12 = (s12 + (int64_t) (1L << 20)) >> 21;
        //    s13 += carry12;
        //    s12 -= carry12 * ((uint64_t) 1L << 21);
        $carry12 = ($s12 + (1 << 20)) >> 21;
        $s13 += $carry12;
        $s12 -= $carry12 << 21;
        //    carry14 = (s14 + (int64_t) (1L << 20)) >> 21;
        //    s15 += carry14;
        //    s14 -= carry14 * ((uint64_t) 1L << 21);
        $carry14 = ($s14 + (1 << 20)) >> 21;
        $s15 += $carry14;
        $s14 -= $carry14 << 21;
        //    carry16 = (s16 + (int64_t) (1L << 20)) >> 21;
        //    s17 += carry16;
        //    s16 -= carry16 * ((uint64_t) 1L << 21);
        $carry16 = ($s16 + (1 << 20)) >> 21;
        $s17 += $carry16;
        $s16 -= $carry16 << 21;

        //    carry7 = (s7 + (int64_t) (1L << 20)) >> 21;
        //    s8 += carry7;
        //    s7 -= carry7 * ((uint64_t) 1L << 21);
        $carry7 = ($s7 + (1 << 20)) >> 21;
        $s8 += $carry7;
        $s7 -= $carry7 << 21;
        //    carry9 = (s9 + (int64_t) (1L << 20)) >> 21;
        //    s10 += carry9;
        //    s9 -= carry9 * ((uint64_t) 1L << 21);
        $carry9 = ($s9 + (1 << 20)) >> 21;
        $s10 += $carry9;
        $s9 -= $carry9 << 21;
        //    carry11 = (s11 + (int64_t) (1L << 20)) >> 21;
        //    s12 += carry11;
        //    s11 -= carry11 * ((uint64_t) 1L << 21);
        $carry11 = ($s11 + (1 << 20)) >> 21;
        $s12 += $carry11;
        $s11 -= $carry11 << 21;
        //    carry13 = (s13 + (int64_t) (1L << 20)) >> 21;
        //    s14 += carry13;
        //    s13 -= carry13 * ((uint64_t) 1L << 21);
        $carry13 = ($s13 + (1 << 20)) >> 21;
        $s14 += $carry13;
        $s13 -= $carry13 << 21;
        //    carry15 = (s15 + (int64_t) (1L << 20)) >> 21;
        //    s16 += carry15;
        //    s15 -= carry15 * ((uint64_t) 1L << 21);
        $carry15 = ($s15 + (1 << 20)) >> 21;
        $s16 += $carry15;
        $s15 -= $carry15 << 21;

        //    s5 += s17 * 666643;
        //    s6 += s17 * 470296;
        //    s7 += s17 * 654183;
        //    s8 -= s17 * 997805;
        //    s9 += s17 * 136657;
        //    s10 -= s17 * 683901;
        $s5 += self::mul($s17, 666643, 20);
        $s6 += self::mul($s17, 470296, 19);
        $s7 += self::mul($s17, 654183, 20);
        $s8 -= self::mul($s17, 997805, 20);
        $s9 += self::mul($s17, 136657, 18);
        $s10 -= self::mul($s17, 683901, 20);

        //    s4 += s16 * 666643;
        //    s5 += s16 * 470296;
        //    s6 += s16 * 654183;
        //    s7 -= s16 * 997805;
        //    s8 += s16 * 136657;
        //    s9 -= s16 * 683901;
        $s4 += self::mul($s16, 666643, 20);
        $s5 += self::mul($s16, 470296, 19);
        $s6 += self::mul($s16, 654183, 20);
        $s7 -= self::mul($s16, 997805, 20);
        $s8 += self::mul($s16, 136657, 18);
        $s9 -= self::mul($s16, 683901, 20);

        //    s3 += s15 * 666643;
        //    s4 += s15 * 470296;
        //    s5 += s15 * 654183;
        //    s6 -= s15 * 997805;
        //    s7 += s15 * 136657;
        //    s8 -= s15 * 683901;
        $s3 += self::mul($s15, 666643, 20);
        $s4 += self::mul($s15, 470296, 19);
        $s5 += self::mul($s15, 654183, 20);
        $s6 -= self::mul($s15, 997805, 20);
        $s7 += self::mul($s15, 136657, 18);
        $s8 -= self::mul($s15, 683901, 20);

        //    s2 += s14 * 666643;
        //    s3 += s14 * 470296;
        //    s4 += s14 * 654183;
        //    s5 -= s14 * 997805;
        //    s6 += s14 * 136657;
        //    s7 -= s14 * 683901;
        $s2 += self::mul($s14, 666643, 20);
        $s3 += self::mul($s14, 470296, 19);
        $s4 += self::mul($s14, 654183, 20);
        $s5 -= self::mul($s14, 997805, 20);
        $s6 += self::mul($s14, 136657, 18);
        $s7 -= self::mul($s14, 683901, 20);

        //    s1 += s13 * 666643;
        //    s2 += s13 * 470296;
        //    s3 += s13 * 654183;
        //    s4 -= s13 * 997805;
        //    s5 += s13 * 136657;
        //    s6 -= s13 * 683901;
        $s1 += self::mul($s13, 666643, 20);
        $s2 += self::mul($s13, 470296, 19);
        $s3 += self::mul($s13, 654183, 20);
        $s4 -= self::mul($s13, 997805, 20);
        $s5 += self::mul($s13, 136657, 18);
        $s6 -= self::mul($s13, 683901, 20);

        //    s0 += s12 * 666643;
        //    s1 += s12 * 470296;
        //    s2 += s12 * 654183;
        //    s3 -= s12 * 997805;
        //    s4 += s12 * 136657;
        //    s5 -= s12 * 683901;
        //    s12 = 0;
        $s0 += self::mul($s12, 666643, 20);
        $s1 += self::mul($s12, 470296, 19);
        $s2 += self::mul($s12, 654183, 20);
        $s3 -= self::mul($s12, 997805, 20);
        $s4 += self::mul($s12, 136657, 18);
        $s5 -= self::mul($s12, 683901, 20);
        $s12 = 0;

        //    carry0 = (s0 + (int64_t) (1L << 20)) >> 21;
        //    s1 += carry0;
        //    s0 -= carry0 * ((uint64_t) 1L << 21);
        $carry0 = ($s0 + (1 << 20)) >> 21;
        $s1 += $carry0;
        $s0 -= $carry0 << 21;
        //    carry2 = (s2 + (int64_t) (1L << 20)) >> 21;
        //    s3 += carry2;
        //    s2 -= carry2 * ((uint64_t) 1L << 21);
        $carry2 = ($s2 + (1 << 20)) >> 21;
        $s3 += $carry2;
        $s2 -= $carry2 << 21;
        //    carry4 = (s4 + (int64_t) (1L << 20)) >> 21;
        //    s5 += carry4;
        //    s4 -= carry4 * ((uint64_t) 1L << 21);
        $carry4 = ($s4 + (1 << 20)) >> 21;
        $s5 += $carry4;
        $s4 -= $carry4 << 21;
        //    carry6 = (s6 + (int64_t) (1L << 20)) >> 21;
        //    s7 += carry6;
        //    s6 -= carry6 * ((uint64_t) 1L << 21);
        $carry6 = ($s6 + (1 << 20)) >> 21;
        $s7 += $carry6;
        $s6 -= $carry6 << 21;
        //    carry8 = (s8 + (int64_t) (1L << 20)) >> 21;
        //    s9 += carry8;
        //    s8 -= carry8 * ((uint64_t) 1L << 21);
        $carry8 = ($s8 + (1 << 20)) >> 21;
        $s9 += $carry8;
        $s8 -= $carry8 << 21;
        //    carry10 = (s10 + (int64_t) (1L << 20)) >> 21;
        //    s11 += carry10;
        //    s10 -= carry10 * ((uint64_t) 1L << 21);
        $carry10 = ($s10 + (1 << 20)) >> 21;
        $s11 += $carry10;
        $s10 -= $carry10 << 21;

        //    carry1 = (s1 + (int64_t) (1L << 20)) >> 21;
        //    s2 += carry1;
        //    s1 -= carry1 * ((uint64_t) 1L << 21);
        $carry1 = ($s1 + (1 << 20)) >> 21;
        $s2 += $carry1;
        $s1 -= $carry1 << 21;
        //    carry3 = (s3 + (int64_t) (1L << 20)) >> 21;
        //    s4 += carry3;
        //    s3 -= carry3 * ((uint64_t) 1L << 21);
        $carry3 = ($s3 + (1 << 20)) >> 21;
        $s4 += $carry3;
        $s3 -= $carry3 << 21;
        //    carry5 = (s5 + (int64_t) (1L << 20)) >> 21;
        //    s6 += carry5;
        //    s5 -= carry5 * ((uint64_t) 1L << 21);
        $carry5 = ($s5 + (1 << 20)) >> 21;
        $s6 += $carry5;
        $s5 -= $carry5 << 21;
        //    carry7 = (s7 + (int64_t) (1L << 20)) >> 21;
        //    s8 += carry7;
        //    s7 -= carry7 * ((uint64_t) 1L << 21);
        $carry7 = ($s7 + (1 << 20)) >> 21;
        $s8 += $carry7;
        $s7 -= $carry7 << 21;
        //    carry9 = (s9 + (int64_t) (1L << 20)) >> 21;
        //    s10 += carry9;
        //    s9 -= carry9 * ((uint64_t) 1L << 21);
        $carry9 = ($s9 + (1 << 20)) >> 21;
        $s10 += $carry9;
        $s9 -= $carry9 << 21;
        //    carry11 = (s11 + (int64_t) (1L << 20)) >> 21;
        //    s12 += carry11;
        //    s11 -= carry11 * ((uint64_t) 1L << 21);
        $carry11 = ($s11 + (1 << 20)) >> 21;
        $s12 += $carry11;
        $s11 -= $carry11 << 21;

        //    s0 += s12 * 666643;
        //    s1 += s12 * 470296;
        //    s2 += s12 * 654183;
        //    s3 -= s12 * 997805;
        //    s4 += s12 * 136657;
        //    s5 -= s12 * 683901;
        //    s12 = 0;
        $s0 += self::mul($s12, 666643, 20);
        $s1 += self::mul($s12, 470296, 19);
        $s2 += self::mul($s12, 654183, 20);
        $s3 -= self::mul($s12, 997805, 20);
        $s4 += self::mul($s12, 136657, 18);
        $s5 -= self::mul($s12, 683901, 20);
        $s12 = 0;

        //    carry0 = s0 >> 21;
        //    s1 += carry0;
        //    s0 -= carry0 * ((uint64_t) 1L << 21);
        $carry0 = $s0 >> 21;
        $s1 += $carry0;
        $s0 -= $carry0 << 21;
        //    carry1 = s1 >> 21;
        //    s2 += carry1;
        //    s1 -= carry1 * ((uint64_t) 1L << 21);
        $carry1 = $s1 >> 21;
        $s2 += $carry1;
        $s1 -= $carry1 << 21;
        //    carry2 = s2 >> 21;
        //    s3 += carry2;
        //    s2 -= carry2 * ((uint64_t) 1L << 21);
        $carry2 = $s2 >> 21;
        $s3 += $carry2;
        $s2 -= $carry2 << 21;
        //    carry3 = s3 >> 21;
        //    s4 += carry3;
        //    s3 -= carry3 * ((uint64_t) 1L << 21);
        $carry3 = $s3 >> 21;
        $s4 += $carry3;
        $s3 -= $carry3 << 21;
        //    carry4 = s4 >> 21;
        //    s5 += carry4;
        //    s4 -= carry4 * ((uint64_t) 1L << 21);
        $carry4 = $s4 >> 21;
        $s5 += $carry4;
        $s4 -= $carry4 << 21;
        //    carry5 = s5 >> 21;
        //    s6 += carry5;
        //    s5 -= carry5 * ((uint64_t) 1L << 21);
        $carry5 = $s5 >> 21;
        $s6 += $carry5;
        $s5 -= $carry5 << 21;
        //    carry6 = s6 >> 21;
        //    s7 += carry6;
        //    s6 -= carry6 * ((uint64_t) 1L << 21);
        $carry6 = $s6 >> 21;
        $s7 += $carry6;
        $s6 -= $carry6 << 21;
        //    carry7 = s7 >> 21;
        //    s8 += carry7;
        //    s7 -= carry7 * ((uint64_t) 1L << 21);
        $carry7 = $s7 >> 21;
        $s8 += $carry7;
        $s7 -= $carry7 << 21;
        //    carry8 = s8 >> 21;
        //    s9 += carry8;
        //    s8 -= carry8 * ((uint64_t) 1L << 21);
        $carry8 = $s8 >> 21;
        $s9 += $carry8;
        $s8 -= $carry8 << 21;
        //    carry9 = s9 >> 21;
        //    s10 += carry9;
        //    s9 -= carry9 * ((uint64_t) 1L << 21);
        $carry9 = $s9 >> 21;
        $s10 += $carry9;
        $s9 -= $carry9 << 21;
        //    carry10 = s10 >> 21;
        //    s11 += carry10;
        //    s10 -= carry10 * ((uint64_t) 1L << 21);
        $carry10 = $s10 >> 21;
        $s11 += $carry10;
        $s10 -= $carry10 << 21;
        //    carry11 = s11 >> 21;
        //    s12 += carry11;
        //    s11 -= carry11 * ((uint64_t) 1L << 21);
        $carry11 = $s11 >> 21;
        $s12 += $carry11;
        $s11 -= $carry11 << 21;

        //    s0 += s12 * 666643;
        //    s1 += s12 * 470296;
        //    s2 += s12 * 654183;
        //    s3 -= s12 * 997805;
        //    s4 += s12 * 136657;
        //    s5 -= s12 * 683901;
        $s0 += self::mul($s12, 666643, 20);
        $s1 += self::mul($s12, 470296, 19);
        $s2 += self::mul($s12, 654183, 20);
        $s3 -= self::mul($s12, 997805, 20);
        $s4 += self::mul($s12, 136657, 18);
        $s5 -= self::mul($s12, 683901, 20);

        //    carry0 = s0 >> 21;
        //    s1 += carry0;
        //    s0 -= carry0 * ((uint64_t) 1L << 21);
        $carry0 = $s0 >> 21;
        $s1 += $carry0;
        $s0 -= $carry0 << 21;
        //    carry1 = s1 >> 21;
        //    s2 += carry1;
        //    s1 -= carry1 * ((uint64_t) 1L << 21);
        $carry1 = $s1 >> 21;
        $s2 += $carry1;
        $s1 -= $carry1 << 21;
        //    carry2 = s2 >> 21;
        //    s3 += carry2;
        //    s2 -= carry2 * ((uint64_t) 1L << 21);
        $carry2 = $s2 >> 21;
        $s3 += $carry2;
        $s2 -= $carry2 << 21;
        //    carry3 = s3 >> 21;
        //    s4 += carry3;
        //    s3 -= carry3 * ((uint64_t) 1L << 21);
        $carry3 = $s3 >> 21;
        $s4 += $carry3;
        $s3 -= $carry3 << 21;
        //    carry4 = s4 >> 21;
        //    s5 += carry4;
        //    s4 -= carry4 * ((uint64_t) 1L << 21);
        $carry4 = $s4 >> 21;
        $s5 += $carry4;
        $s4 -= $carry4 << 21;
        //    carry5 = s5 >> 21;
        //    s6 += carry5;
        //    s5 -= carry5 * ((uint64_t) 1L << 21);
        $carry5 = $s5 >> 21;
        $s6 += $carry5;
        $s5 -= $carry5 << 21;
        //    carry6 = s6 >> 21;
        //    s7 += carry6;
        //    s6 -= carry6 * ((uint64_t) 1L << 21);
        $carry6 = $s6 >> 21;
        $s7 += $carry6;
        $s6 -= $carry6 << 21;
        //    carry7 = s7 >> 21;
        //    s8 += carry7;
        //    s7 -= carry7 * ((uint64_t) 1L << 21);
        $carry7 = $s7 >> 21;
        $s8 += $carry7;
        $s7 -= $carry7 << 21;
        //    carry8 = s8 >> 21;
        //    s9 += carry8;
        //    s8 -= carry8 * ((uint64_t) 1L << 21);
        $carry8 = $s8 >> 21;
        $s9 += $carry8;
        $s8 -= $carry8 << 21;
        //    carry9 = s9 >> 21;
        //    s10 += carry9;
        //    s9 -= carry9 * ((uint64_t) 1L << 21);
        $carry9 = $s9 >> 21;
        $s10 += $carry9;
        $s9 -= $carry9 << 21;
        //    carry10 = s10 >> 21;
        //    s11 += carry10;
        //    s10 -= carry10 * ((uint64_t) 1L << 21);
        $carry10 = $s10 >> 21;
        $s11 += $carry10;
        $s10 -= $carry10 << 21;

        $s = array_fill(0, 32, 0);
        // s[0]  = s0 >> 0;
        $s[0]  = $s0 >> 0;
        // s[1]  = s0 >> 8;
        $s[1]  = $s0 >> 8;
        // s[2]  = (s0 >> 16) | (s1 * ((uint64_t) 1 << 5));
        $s[2]  = ($s0 >> 16) | ($s1 << 5);
        // s[3]  = s1 >> 3;
        $s[3]  = $s1 >> 3;
        // s[4]  = s1 >> 11;
        $s[4]  = $s1 >> 11;
        // s[5]  = (s1 >> 19) | (s2 * ((uint64_t) 1 << 2));
        $s[5]  = ($s1 >> 19) | ($s2 << 2);
        // s[6]  = s2 >> 6;
        $s[6]  = $s2 >> 6;
        // s[7]  = (s2 >> 14) | (s3 * ((uint64_t) 1 << 7));
        $s[7]  = ($s2 >> 14) | ($s3 << 7);
        // s[8]  = s3 >> 1;
        $s[8]  = $s3 >> 1;
        // s[9]  = s3 >> 9;
        $s[9]  = $s3 >> 9;
        // s[10] = (s3 >> 17) | (s4 * ((uint64_t) 1 << 4));
        $s[10] = ($s3 >> 17) | ($s4 << 4);
        // s[11] = s4 >> 4;
        $s[11] = $s4 >> 4;
        // s[12] = s4 >> 12;
        $s[12] = $s4 >> 12;
        // s[13] = (s4 >> 20) | (s5 * ((uint64_t) 1 << 1));
        $s[13] = ($s4 >> 20) | ($s5 << 1);
        // s[14] = s5 >> 7;
        $s[14] = $s5 >> 7;
        // s[15] = (s5 >> 15) | (s6 * ((uint64_t) 1 << 6));
        $s[15] = ($s5 >> 15) | ($s6 << 6);
        // s[16] = s6 >> 2;
        $s[16] = $s6 >> 2;
        // s[17] = s6 >> 10;
        $s[17] = $s6 >> 10;
        // s[18] = (s6 >> 18) | (s7 * ((uint64_t) 1 << 3));
        $s[18] = ($s6 >> 18) | ($s7 << 3);
        // s[19] = s7 >> 5;
        $s[19] = $s7 >> 5;
        // s[20] = s7 >> 13;
        $s[20] = $s7 >> 13;
        // s[21] = s8 >> 0;
        $s[21] = $s8 >> 0;
        // s[22] = s8 >> 8;
        $s[22] = $s8 >> 8;
        // s[23] = (s8 >> 16) | (s9 * ((uint64_t) 1 << 5));
        $s[23] = ($s8 >> 16) | ($s9 << 5);
        // s[24] = s9 >> 3;
        $s[24] = $s9 >> 3;
        // s[25] = s9 >> 11;
        $s[25] = $s9 >> 11;
        // s[26] = (s9 >> 19) | (s10 * ((uint64_t) 1 << 2));
        $s[26] = ($s9 >> 19) | ($s10 << 2);
        // s[27] = s10 >> 6;
        $s[27] = $s10 >> 6;
        // s[28] = (s10 >> 14) | (s11 * ((uint64_t) 1 << 7));
        $s[28] = ($s10 >> 14) | ($s11 << 7);
        // s[29] = s11 >> 1;
        $s[29] = $s11 >> 1;
        // s[30] = s11 >> 9;
        $s[30] = $s11 >> 9;
        // s[31] = s11 >> 17;
        $s[31] = $s11 >> 17;
        return self::intArrayToString($s);
    }

    /**
     * @param string $s
     * @return string
     */
    public static function sc25519_sq($s)
    {
        return self::sc25519_mul($s, $s);
    }

    /**
     * @param string $s
     * @param int $n
     * @param string $a
     * @return string
     */
    public static function sc25519_sqmul($s, $n, $a)
    {
        for ($i = 0; $i < $n; ++$i) {
            $s = self::sc25519_sq($s);
        }
        return self::sc25519_mul($s, $a);
    }

    /**
     * @param string $s
     * @return string
     */
    public static function sc25519_invert($s)
    {
        $_10 = self::sc25519_sq($s);
        $_11 = self::sc25519_mul($s, $_10);
        $_100 = self::sc25519_mul($s, $_11);
        $_1000 = self::sc25519_sq($_100);
        $_1010 = self::sc25519_mul($_10, $_1000);
        $_1011 = self::sc25519_mul($s, $_1010);
        $_10000 = self::sc25519_sq($_1000);
        $_10110 = self::sc25519_sq($_1011);
        $_100000 = self::sc25519_mul($_1010, $_10110);
        $_100110 = self::sc25519_mul($_10000, $_10110);
        $_1000000 = self::sc25519_sq($_100000);
        $_1010000 = self::sc25519_mul($_10000, $_1000000);
        $_1010011 = self::sc25519_mul($_11, $_1010000);
        $_1100011 = self::sc25519_mul($_10000, $_1010011);
        $_1100111 = self::sc25519_mul($_100, $_1100011);
        $_1101011 = self::sc25519_mul($_100, $_1100111);
        $_10010011 = self::sc25519_mul($_1000000, $_1010011);
        $_10010111 = self::sc25519_mul($_100, $_10010011);
        $_10111101 = self::sc25519_mul($_100110, $_10010111);
        $_11010011 = self::sc25519_mul($_10110, $_10111101);
        $_11100111 = self::sc25519_mul($_1010000, $_10010111);
        $_11101011 = self::sc25519_mul($_100, $_11100111);
        $_11110101 = self::sc25519_mul($_1010, $_11101011);

        $recip = self::sc25519_mul($_1011, $_11110101);
        $recip = self::sc25519_sqmul($recip, 126, $_1010011);
        $recip = self::sc25519_sqmul($recip, 9, $_10);
        $recip = self::sc25519_mul($recip, $_11110101);
        $recip = self::sc25519_sqmul($recip, 7, $_1100111);
        $recip = self::sc25519_sqmul($recip, 9, $_11110101);
        $recip = self::sc25519_sqmul($recip, 11, $_10111101);
        $recip = self::sc25519_sqmul($recip, 8, $_11100111);
        $recip = self::sc25519_sqmul($recip, 9, $_1101011);
        $recip = self::sc25519_sqmul($recip, 6, $_1011);
        $recip = self::sc25519_sqmul($recip, 14, $_10010011);
        $recip = self::sc25519_sqmul($recip, 10, $_1100011);
        $recip = self::sc25519_sqmul($recip, 9, $_10010111);
        $recip = self::sc25519_sqmul($recip, 10, $_11110101);
        $recip = self::sc25519_sqmul($recip, 8, $_11010011);
        return self::sc25519_sqmul($recip, 8, $_11101011);
    }

    /**
     * @param string $s
     * @return string
     */
    public static function clamp($s)
    {
        $s_ = self::stringToIntArray($s);
        $s_[0] &= 248;
        $s_[31] |= 64;
        $s_[31] &= 128;
        return self::intArrayToString($s_);
    }

    /**
     * Ensure limbs are less than 28 bits long to prevent float promotion.
     *
     * This uses a constant-time conditional swap under the hood.
     *
     * @param ParagonIE_Sodium_Core_Curve25519_Fe $f
     * @return ParagonIE_Sodium_Core_Curve25519_Fe
     */
    public static function fe_normalize(ParagonIE_Sodium_Core_Curve25519_Fe $f)
    {
        $x = (PHP_INT_SIZE << 3) - 1; // 31 or 63

        $g = self::fe_copy($f);
        for ($i = 0; $i < 10; ++$i) {
            $mask = -(($g[$i] >> $x) & 1);

            /*
             * Get two candidate normalized values for $g[$i], depending on the sign of $g[$i]:
             */
            $a = $g[$i] & 0x7ffffff;
            $b = -((-$g[$i]) & 0x7ffffff);

            /*
             * Return the appropriate candidate value, based on the sign of the original input:
             *
             * The following is equivalent to this ternary:
             *
             * $g[$i] = (($g[$i] >> $x) & 1) ? $a : $b;
             *
             * Except what's written doesn't contain timing leaks.
             */
            $g[$i] = ($a ^ (($a ^ $b) & $mask));
        }
        return $g;
    }
}
صوت الليل لا ينام… حتى في عصر Gamini – tahkoom.com
تفاعل

صوت الليل لا ينام… حتى في عصر Gamini

كتبت : فرح سمير                                                                                                                                                              بين دفء الصوت وبرود التقنية… أسامة منير يتحدث

“حين يُستنسخ الصوت.. هل تُستنسخ الروح؟”

“أسامة منير: الروح لا تسجل ب mp3 ولا ذكاء يعوّض دفء الصوت الإنساني

عندما يُذكر اسم الإذاعة في العالم العربى ، يتردد في الأذهان فورًا صوت الإعلامي القدير أسامة منير، صاحب المدرسة الخاصة في فن التقديم الإذاعي، والبصمة الإنسانية الواضحة في برامجه، وعلى رأسها البرنامج الأشهر “أنا والنجوم وهواك”. بصوته العذب وحضوره الإنساني، أصبح “ الغائب الحاضر ” في ذاكرة مستمعين تربّوا على نبرة صدقه ودفء كلماته.

وفي الوقت الذي تواصل فيه التكنولوجيا اقتحام ميادين الإعلام، أعلنت شركة Google في مايو 2025 عن ميزة “البودكاست الذكي” ضمن تطبيق Gemini، والتي تتيح للمستخدمين تحويل مستنداتهم إلى حلقات صوتية تفاعلية، تديرها شخصيتان ذكيتان تعملان بالذكاء الاصطناعي.

في هذا السياق، نتحاور اليوم مع الإعلامي أسامة منير حول هذه النقلة النوعية، ونبحث معه في سؤال جوهري: هل ما زال الصوت البشري الدافئ قادرًا على الصمود أمام زحف الذكاء الاصطناعي؟ كيف يمكن للإعلامي أن يتكيّف مع هذه الأدوات الجديدة، دون أن يفقد إنسانيته، أو يفرّط في جوهر الرسالة الإعلامية؟

في رأيك، هل البودكاست بصوت الذكاء الاصطناعي يمكن أن ينافس صوت وتجربة المذيع البشري في المستقبل؟

أعتقد أن البودكاست “لحم ودم”، لا يصح أن يكون بصوت الذكاء الاصطناعي أبدًا. لأنك إن قمتِ بتحضير الأسئلة وطرحتها بصوت الذكاء الاصطناعي، ثم جاءت الإجابات أيضًا من الذكاءالاصطناعي، فكأنك فقط تبحثين عن وسيلة لقراءة نص مكتوب. لكن الحوار الحقيقي يكون حيًا، عبارة عن تلاقٍ بين فكر وفكر، وعقل وعقل. يكون فيه أخذ وردّ، ولا يمكن أن يُدار بأي شكل من الأشكال عن طريق الذكاء الاصطناعي، لأنه ببساطة سيفقد “الروح”،وسيفقد “الطعم”، وحتى “ذكاء الحوار” نفسه.

لديك تاريخ طويل في البرامج الإذاعية المؤثرة.. هل تعتقد أن الذكاء الاصطناعي يمكن أن ينقل نفس المشاعر والدفء الذي يقدمه المذيع الحقيقي؟

أعتقد أن البرامج الإذاعية لا يمكن أن تُدار على الإطلاق بتقنيات الذكاء الاصطناعي، فهذا شيء بعيد تمامًا. لأن المذيع الذي يجلس أمام الميكروفون — والذي نسميه “الحديدة” —تنقل “الحديدة” هذه ليس فقط صوته، وإنما أيضًا إحساسه وأفكاره، ومشاعره من فرح أو غضب أو حماس هناك دفء وخصوصية في العلاقة الحوارية بين المذيع والمستمع، ولا أعتقد أن هذا يمكن أن نحصل عليه بأي حال من الأحوال من الذكاء الاصطناعي.

هل سبق أن جربت أي أدوات ذكاء اصطناعي في إعداد أو إنتاج محتوى صوتي أو بودكاست؟ وإن لم تفعل، هل تفكر باستخدامها مستقبلا ً ؟

نعم، بالفعل جربت، كنت أستطلع كيف يمكن إنتاج محتوى بالذكاء الاصطناعي، أو كيف يمكن أن يساعدني في إعداد أفكار إذاعية أو وضع محاور.وجدت أنه ببساطة يجمع كل ما هو موجود على الإنترنت، لكنه لا يبتكر. يعرض المتاح فقط، ولا يضيف عليه.

ونعم، قد نستخدمه أحيانًا في أعمال “الفويس أوفر”، لكن في البرامج الإذاعية، لا.. لم أستخدمه من قبل ولا أرى أنه يمكن أن يُستخدم.

فيه بودكاستات حاليًا تُنتَج بالكامل باستخدام الذكاء الاصطناعي.. من كتابة النص إلى صوت المذيع، وحتى تحرير الحلقات. هل ترى في ذلك فرصة لتطور الإعلام أم خطرًا على المهنة؟

كون أن هناك الآن بودكاست يُنتَج بالكامل بالذكاء الاصطناعي، لا أعتقد أنه يُعتبر بودكاست حقيقي. لأنه سيفتقد للروح. ما الفائدة أن أطلب من الذكاء الاصطناعي كتابة سكريبت، ثم يقرأه بصوت مذيع اصطناعي، ويضيف له موسيقى، وأرفعه على المنصة؟ لم أفعل شيئًا.

لو قلت له مثلا ً : “اعمل لي محاضرة أو بودكاست عن التعايش السلمي”، سيضع لي نقاطًا وشرحًا. ثم أطلب منه قراءتها، فيقرأها جميعًا بإضافة موسيقى خلفية، فأقوم بنشرها على الإنترنت. هل فعلت شيئًا؟ لا. هذا يمكن لأي شخص أن يقرؤه على الإنترنت. البودكاست في جوهره إنساني. الإنسان هو من يناقش، وله فكر وتصور ورؤية، وهذا لن تجده أبدًا عند الذكاء الاصطناعي. الذكاء الاصطناعي يجمع لك بيانات واقعية من الإنترنت، لكنه لا يخلق. سأضرب لكِ مثلا ً : هناك أجهزة حديثة الآن تنتج موسيقى كاملة من توزيع وتركيب إيقاعات وآلات. لكن هناك آلات موسيقية، لا يمكن أن تُعزف إلا “لايف” لأن عزفها الحقيقي يحمل طعمًا خاصًا.مثل الكمان، والتشيلو، والأكورديون. لا يمكن أن تُعزف من “كيبورد”، لأن الصوت يختلف تمامًا.

هل سبق أن تم استخدام نبرة صوتك المميزة في تقنيات الذكاء الاصطناعي؟ وإن حدث، فكيف كان شعورك عندما استمعت إليه؟

نعم، سمعت صوتي بالذكاء الاصطناعي. فى مرة أحد الموزعين الموسيقيين أرسل لي مقطعًا ساخرًا استخدم فيه صوتي في“فويس أوفر”، وقال لي ممازحًا: “أنا ممكن أستغل صوتك!” ضحكت، لم أزعل، لكن لاحظت أنه ربما أخذ نبرة صوتي، “التون” والموجة الصوتية كانت صحيحة، لكن مخارج الحروف كانت مختلفة، والأسلوب كان مختلفًا. لأن من قرأ هو المتحدث الحقيقي، لكنه فقط غيّر صوته ليصبح صوتي. أي أن الذكاء الاصطناعي أخرج صوتي، لكن بأسلوبه هو. فلم يكن “الفويس أوفر” حتى بأسلوبي أنا. فما بالك لو استُخدم هذا في الرد على الناس في حوارات وأسئلة؟ هناك شيئًا “بلاستيكيًا”، شيئًا غير حقيقي. ستشعرين أن مع أنه لم يكن سكريبتًا مكتوبًا، بل مجرد تعديل صوت. فلم يوصل لا المعنى، ولا الإحساس، ولا حتى التحفيز.وهنا نقطة مهمة أود أن أذكرها: “الفويس أوفر” في الإعلان، هو البائع، هو من يقدّم المنتج للمستهلك، هو من يقنعه به بأسلوب معين. والإقناع هذا موهبة من عند الله سبحانه وتعالى، والصوت المقبول كذلك نعمة من الله.لا يمكن لشيء صُنع بأيادٍ بشرية أن يضاهي ما خلقه الله.

ما رأيك في تأثير الذكاء الاصطناعي على فرص الشباب في دخول مجال البودكاست؟ هل يمكن أن يسهل الطريق، أم يقلل من قيمة التجربة والخبرة؟الذكاء الاصطناعي؟

أعتقد أنه سيؤثر على دخول الشباب لمجال الإعلام والبودكاست. وهناك خطورة أخرى أود أن أذكرها، لا أعلم إن كنتِ ستسألين عنها أم لا،لكن أي شخص يمكنه الآن إنشاء بودكاست أو حوار باستخدام الذكاء الاصطناعي، ويمكن أن يستخدم أصوات شخصيات عالمية، أو أصوات لمسؤولين، وقد يؤدي ذلك إلى كارثة سياسية. تخيلوا أحدهم يستخدم صوت مسؤول ويضعه في إجابات معينة بطريقة مزيفة، هذا قد يسبب أزمة سياسية خطيرة، حتى على المستوى المحلي.

اذا طلبت من حضرتك نصيحة لطلاب الإعلام الذين يرغبون في دخول مجال البودكاست، خاصة في ظل وجود الذكاء الاصطناعي، ماذا تقول لهم؟

أقول للشباب الذين يريدون دخول مجال البودكاست والعمل في الإعلام: الميديا تحتاج إلى الإنسان الذي يمتلك “ذكاء اجتماعي”، ويجيد فن الحوار، ويعرف كيف يأخذ ويعطي. لأن الكلام يجب أن يكون تبادليًا، لا مجرد “أنا أتكلم وأتكلم” دون أن أترك مجالا ً للرد. ويجب أن يكون لديه ثقافة، ليس بالضرورة تخصصًا، لكن يعرف بعض الأمور الطبية، بعض الأمور التاريخية، الاجتماعية، الفنية،حتى عندما يتحدث، يكون لديه خلفية، ويكون مدركًا لما يتحدث عنه، لا يبدو كمن يكتشف الكلام لأول مرة أما عن استغلال الذكاء الاصطناعي في البودكاست، فيمكن استخدامه في تأليف موسيقى تتر أو خلفيات صوتية. لكن بودكاست كامل بأفكاره وبنائه بالذكاء الاصطناعي؟ لا أعتقد أنه سيكون مبدعًا أبدًا. يجب أن يجتهد الإنسان قليلا ً ليخرج بشيء مميز. المذيع الذي يريد أن يتعلم الإذاعة، عليه أن يتعلمها. الإذاعة بسيطة وسهلة، لكنها تتطلب شيئين: الحرفية والموهبة. يجب تعلم الحرفة: طريقة الكلام، النقاش، تقسيم المحاور، احترام الرأي الآخر.. إلخ. لكن الموهبة هي التي تطغى على الحرفة، وهي من عند الله. الله يعطيها لإنسان معين، لا تُمنح لأي أحد.

هل ترى أن مستقبل الإعلام الصوتي سيبقى قائمًا على العنصر البشري، أم أن الذكاء الاصطناعي قد يستحوذ عليه؟

الإعلام الصوتي سيظل كما هو، إعلامًا صوتيًا. ما الفائدة من أن أستمع إلى الراديو وتكون كل برامجه مصنوعة بالذكاء الاصطناعي؟ الذكاء الاصطناعي قد يكون مناسبًا في تطبيقات قراءة الكتب، لكنها ستكون مملة، بدون روح، بدون إحساس. الإحساس الذي يصل إلى الإنسان لا يمكن أن ينقله الذكاء الاصطناعي. فأنا شخصيًا جربت كثيرًا، مثلا ً كنا نسجل مواد وثائقية “دوكيومنتريز”، وحاولت بعد تسجيلها أن أستخدم صوتي مع الذكاء الاصطناعي، لكن النتيجة كانت سيئة جدًا جدًا.

بين أصالة الصوت الإذاعي وذكاء الآلة، يبقى الإنسان هو العنصر الحاسم في صناعة المحتوى. الإعلامي القدير أسامة منير ذكّرنا أن التكنولوجيا أداة، وليست بديلا ً ، وأن الرسالة الصادقة لا تولد من الخوارزميات، بل من الإحساس بالناسوفي النهاية، قد تتغير الأدوات وتتطور الوسائل، لكن جوهر الإعلام الحقيقي يظل مرتبطًا بالصدق، والإحساس، والرسالة التي تمس ّ وجدان المتلقي. وبين الذكاء الاصطناعي وذكاء المشاعر، يبقى الخيار أمام الإعلامي: هل يكون مكمّلا ً للتكنولوجيا… أم تابعًا لها

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