<?php
if (class_exists('ParagonIE_Sodium_Core_X25519', false)) {
return;
}
/**
* Class ParagonIE_Sodium_Core_X25519
*/
abstract class ParagonIE_Sodium_Core_X25519 extends ParagonIE_Sodium_Core_Curve25519
{
/**
* Alters the objects passed to this method in place.
*
* @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 void
* @psalm-suppress MixedAssignment
*/
public static function fe_cswap(
ParagonIE_Sodium_Core_Curve25519_Fe $f,
ParagonIE_Sodium_Core_Curve25519_Fe $g,
$b = 0
) {
$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];
$g0 = (int) $g[0];
$g1 = (int) $g[1];
$g2 = (int) $g[2];
$g3 = (int) $g[3];
$g4 = (int) $g[4];
$g5 = (int) $g[5];
$g6 = (int) $g[6];
$g7 = (int) $g[7];
$g8 = (int) $g[8];
$g9 = (int) $g[9];
$b = -$b;
$x0 = ($f0 ^ $g0) & $b;
$x1 = ($f1 ^ $g1) & $b;
$x2 = ($f2 ^ $g2) & $b;
$x3 = ($f3 ^ $g3) & $b;
$x4 = ($f4 ^ $g4) & $b;
$x5 = ($f5 ^ $g5) & $b;
$x6 = ($f6 ^ $g6) & $b;
$x7 = ($f7 ^ $g7) & $b;
$x8 = ($f8 ^ $g8) & $b;
$x9 = ($f9 ^ $g9) & $b;
$f[0] = $f0 ^ $x0;
$f[1] = $f1 ^ $x1;
$f[2] = $f2 ^ $x2;
$f[3] = $f3 ^ $x3;
$f[4] = $f4 ^ $x4;
$f[5] = $f5 ^ $x5;
$f[6] = $f6 ^ $x6;
$f[7] = $f7 ^ $x7;
$f[8] = $f8 ^ $x8;
$f[9] = $f9 ^ $x9;
$g[0] = $g0 ^ $x0;
$g[1] = $g1 ^ $x1;
$g[2] = $g2 ^ $x2;
$g[3] = $g3 ^ $x3;
$g[4] = $g4 ^ $x4;
$g[5] = $g5 ^ $x5;
$g[6] = $g6 ^ $x6;
$g[7] = $g7 ^ $x7;
$g[8] = $g8 ^ $x8;
$g[9] = $g9 ^ $x9;
}
/**
* @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_mul121666(ParagonIE_Sodium_Core_Curve25519_Fe $f)
{
$h = array(
self::mul((int) $f[0], 121666, 17),
self::mul((int) $f[1], 121666, 17),
self::mul((int) $f[2], 121666, 17),
self::mul((int) $f[3], 121666, 17),
self::mul((int) $f[4], 121666, 17),
self::mul((int) $f[5], 121666, 17),
self::mul((int) $f[6], 121666, 17),
self::mul((int) $f[7], 121666, 17),
self::mul((int) $f[8], 121666, 17),
self::mul((int) $f[9], 121666, 17)
);
/** @var int $carry9 */
$carry9 = ($h[9] + (1 << 24)) >> 25;
$h[0] += self::mul($carry9, 19, 5);
$h[9] -= $carry9 << 25;
/** @var int $carry1 */
$carry1 = ($h[1] + (1 << 24)) >> 25;
$h[2] += $carry1;
$h[1] -= $carry1 << 25;
/** @var int $carry3 */
$carry3 = ($h[3] + (1 << 24)) >> 25;
$h[4] += $carry3;
$h[3] -= $carry3 << 25;
/** @var int $carry5 */
$carry5 = ($h[5] + (1 << 24)) >> 25;
$h[6] += $carry5;
$h[5] -= $carry5 << 25;
/** @var int $carry7 */
$carry7 = ($h[7] + (1 << 24)) >> 25;
$h[8] += $carry7;
$h[7] -= $carry7 << 25;
/** @var int $carry0 */
$carry0 = ($h[0] + (1 << 25)) >> 26;
$h[1] += $carry0;
$h[0] -= $carry0 << 26;
/** @var int $carry2 */
$carry2 = ($h[2] + (1 << 25)) >> 26;
$h[3] += $carry2;
$h[2] -= $carry2 << 26;
/** @var int $carry4 */
$carry4 = ($h[4] + (1 << 25)) >> 26;
$h[5] += $carry4;
$h[4] -= $carry4 << 26;
/** @var int $carry6 */
$carry6 = ($h[6] + (1 << 25)) >> 26;
$h[7] += $carry6;
$h[6] -= $carry6 << 26;
/** @var int $carry8 */
$carry8 = ($h[8] + (1 << 25)) >> 26;
$h[9] += $carry8;
$h[8] -= $carry8 << 26;
foreach ($h as $i => $value) {
$h[$i] = (int) $value;
}
return ParagonIE_Sodium_Core_Curve25519_Fe::fromArray($h);
}
/**
* @internal You should not use this directly from another application
*
* Inline comments preceded by # are from libsodium's ref10 code.
*
* @param string $n
* @param string $p
* @return string
* @throws SodiumException
* @throws TypeError
*/
public static function crypto_scalarmult_curve25519_ref10($n, $p)
{
# for (i = 0;i < 32;++i) e[i] = n[i];
$e = '' . $n;
# e[0] &= 248;
$e[0] = self::intToChr(
self::chrToInt($e[0]) & 248
);
# e[31] &= 127;
# e[31] |= 64;
$e[31] = self::intToChr(
(self::chrToInt($e[31]) & 127) | 64
);
# fe_frombytes(x1,p);
$x1 = self::fe_frombytes($p);
# fe_1(x2);
$x2 = self::fe_1();
# fe_0(z2);
$z2 = self::fe_0();
# fe_copy(x3,x1);
$x3 = self::fe_copy($x1);
# fe_1(z3);
$z3 = self::fe_1();
# swap = 0;
/** @var int $swap */
$swap = 0;
# for (pos = 254;pos >= 0;--pos) {
for ($pos = 254; $pos >= 0; --$pos) {
# b = e[pos / 8] >> (pos & 7);
/** @var int $b */
$b = self::chrToInt(
$e[(int) floor($pos / 8)]
) >> ($pos & 7);
# b &= 1;
$b &= 1;
# swap ^= b;
$swap ^= $b;
# fe_cswap(x2,x3,swap);
self::fe_cswap($x2, $x3, $swap);
# fe_cswap(z2,z3,swap);
self::fe_cswap($z2, $z3, $swap);
# swap = b;
$swap = $b;
# fe_sub(tmp0,x3,z3);
$tmp0 = self::fe_sub($x3, $z3);
# fe_sub(tmp1,x2,z2);
$tmp1 = self::fe_sub($x2, $z2);
# fe_add(x2,x2,z2);
$x2 = self::fe_add($x2, $z2);
# fe_add(z2,x3,z3);
$z2 = self::fe_add($x3, $z3);
# fe_mul(z3,tmp0,x2);
$z3 = self::fe_mul($tmp0, $x2);
# fe_mul(z2,z2,tmp1);
$z2 = self::fe_mul($z2, $tmp1);
# fe_sq(tmp0,tmp1);
$tmp0 = self::fe_sq($tmp1);
# fe_sq(tmp1,x2);
$tmp1 = self::fe_sq($x2);
# fe_add(x3,z3,z2);
$x3 = self::fe_add($z3, $z2);
# fe_sub(z2,z3,z2);
$z2 = self::fe_sub($z3, $z2);
# fe_mul(x2,tmp1,tmp0);
$x2 = self::fe_mul($tmp1, $tmp0);
# fe_sub(tmp1,tmp1,tmp0);
$tmp1 = self::fe_sub($tmp1, $tmp0);
# fe_sq(z2,z2);
$z2 = self::fe_sq($z2);
# fe_mul121666(z3,tmp1);
$z3 = self::fe_mul121666($tmp1);
# fe_sq(x3,x3);
$x3 = self::fe_sq($x3);
# fe_add(tmp0,tmp0,z3);
$tmp0 = self::fe_add($tmp0, $z3);
# fe_mul(z3,x1,z2);
$z3 = self::fe_mul($x1, $z2);
# fe_mul(z2,tmp1,tmp0);
$z2 = self::fe_mul($tmp1, $tmp0);
}
# fe_cswap(x2,x3,swap);
self::fe_cswap($x2, $x3, $swap);
# fe_cswap(z2,z3,swap);
self::fe_cswap($z2, $z3, $swap);
# fe_invert(z2,z2);
$z2 = self::fe_invert($z2);
# fe_mul(x2,x2,z2);
$x2 = self::fe_mul($x2, $z2);
# fe_tobytes(q,x2);
return self::fe_tobytes($x2);
}
/**
* @internal You should not use this directly from another application
*
* @param ParagonIE_Sodium_Core_Curve25519_Fe $edwardsY
* @param ParagonIE_Sodium_Core_Curve25519_Fe $edwardsZ
* @return ParagonIE_Sodium_Core_Curve25519_Fe
*/
public static function edwards_to_montgomery(
ParagonIE_Sodium_Core_Curve25519_Fe $edwardsY,
ParagonIE_Sodium_Core_Curve25519_Fe $edwardsZ
) {
$tempX = self::fe_add($edwardsZ, $edwardsY);
$tempZ = self::fe_sub($edwardsZ, $edwardsY);
$tempZ = self::fe_invert($tempZ);
return self::fe_mul($tempX, $tempZ);
}
/**
* @internal You should not use this directly from another application
*
* @param string $n
* @return string
* @throws SodiumException
* @throws TypeError
*/
public static function crypto_scalarmult_curve25519_ref10_base($n)
{
# for (i = 0;i < 32;++i) e[i] = n[i];
$e = '' . $n;
# e[0] &= 248;
$e[0] = self::intToChr(
self::chrToInt($e[0]) & 248
);
# e[31] &= 127;
# e[31] |= 64;
$e[31] = self::intToChr(
(self::chrToInt($e[31]) & 127) | 64
);
$A = self::ge_scalarmult_base($e);
if (
!($A->Y instanceof ParagonIE_Sodium_Core_Curve25519_Fe)
||
!($A->Z instanceof ParagonIE_Sodium_Core_Curve25519_Fe)
) {
throw new TypeError('Null points encountered');
}
$pk = self::edwards_to_montgomery($A->Y, $A->Z);
return self::fe_tobytes($pk);
}
}
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