<?php
if (class_exists('ParagonIE_Sodium_Core_Salsa20', false)) {
return;
}
/**
* Class ParagonIE_Sodium_Core_Salsa20
*/
abstract class ParagonIE_Sodium_Core_Salsa20 extends ParagonIE_Sodium_Core_Util
{
const ROUNDS = 20;
/**
* Calculate an salsa20 hash of a single block
*
* @internal You should not use this directly from another application
*
* @param string $in
* @param string $k
* @param string|null $c
* @return string
* @throws TypeError
*/
public static function core_salsa20($in, $k, $c = null)
{
if (self::strlen($k) < 32) {
throw new RangeException('Key must be 32 bytes long');
}
if ($c === null) {
$j0 = $x0 = 0x61707865;
$j5 = $x5 = 0x3320646e;
$j10 = $x10 = 0x79622d32;
$j15 = $x15 = 0x6b206574;
} else {
$j0 = $x0 = self::load_4(self::substr($c, 0, 4));
$j5 = $x5 = self::load_4(self::substr($c, 4, 4));
$j10 = $x10 = self::load_4(self::substr($c, 8, 4));
$j15 = $x15 = self::load_4(self::substr($c, 12, 4));
}
$j1 = $x1 = self::load_4(self::substr($k, 0, 4));
$j2 = $x2 = self::load_4(self::substr($k, 4, 4));
$j3 = $x3 = self::load_4(self::substr($k, 8, 4));
$j4 = $x4 = self::load_4(self::substr($k, 12, 4));
$j6 = $x6 = self::load_4(self::substr($in, 0, 4));
$j7 = $x7 = self::load_4(self::substr($in, 4, 4));
$j8 = $x8 = self::load_4(self::substr($in, 8, 4));
$j9 = $x9 = self::load_4(self::substr($in, 12, 4));
$j11 = $x11 = self::load_4(self::substr($k, 16, 4));
$j12 = $x12 = self::load_4(self::substr($k, 20, 4));
$j13 = $x13 = self::load_4(self::substr($k, 24, 4));
$j14 = $x14 = self::load_4(self::substr($k, 28, 4));
for ($i = self::ROUNDS; $i > 0; $i -= 2) {
$x4 ^= self::rotate($x0 + $x12, 7);
$x8 ^= self::rotate($x4 + $x0, 9);
$x12 ^= self::rotate($x8 + $x4, 13);
$x0 ^= self::rotate($x12 + $x8, 18);
$x9 ^= self::rotate($x5 + $x1, 7);
$x13 ^= self::rotate($x9 + $x5, 9);
$x1 ^= self::rotate($x13 + $x9, 13);
$x5 ^= self::rotate($x1 + $x13, 18);
$x14 ^= self::rotate($x10 + $x6, 7);
$x2 ^= self::rotate($x14 + $x10, 9);
$x6 ^= self::rotate($x2 + $x14, 13);
$x10 ^= self::rotate($x6 + $x2, 18);
$x3 ^= self::rotate($x15 + $x11, 7);
$x7 ^= self::rotate($x3 + $x15, 9);
$x11 ^= self::rotate($x7 + $x3, 13);
$x15 ^= self::rotate($x11 + $x7, 18);
$x1 ^= self::rotate($x0 + $x3, 7);
$x2 ^= self::rotate($x1 + $x0, 9);
$x3 ^= self::rotate($x2 + $x1, 13);
$x0 ^= self::rotate($x3 + $x2, 18);
$x6 ^= self::rotate($x5 + $x4, 7);
$x7 ^= self::rotate($x6 + $x5, 9);
$x4 ^= self::rotate($x7 + $x6, 13);
$x5 ^= self::rotate($x4 + $x7, 18);
$x11 ^= self::rotate($x10 + $x9, 7);
$x8 ^= self::rotate($x11 + $x10, 9);
$x9 ^= self::rotate($x8 + $x11, 13);
$x10 ^= self::rotate($x9 + $x8, 18);
$x12 ^= self::rotate($x15 + $x14, 7);
$x13 ^= self::rotate($x12 + $x15, 9);
$x14 ^= self::rotate($x13 + $x12, 13);
$x15 ^= self::rotate($x14 + $x13, 18);
}
$x0 += $j0;
$x1 += $j1;
$x2 += $j2;
$x3 += $j3;
$x4 += $j4;
$x5 += $j5;
$x6 += $j6;
$x7 += $j7;
$x8 += $j8;
$x9 += $j9;
$x10 += $j10;
$x11 += $j11;
$x12 += $j12;
$x13 += $j13;
$x14 += $j14;
$x15 += $j15;
return self::store32_le($x0) .
self::store32_le($x1) .
self::store32_le($x2) .
self::store32_le($x3) .
self::store32_le($x4) .
self::store32_le($x5) .
self::store32_le($x6) .
self::store32_le($x7) .
self::store32_le($x8) .
self::store32_le($x9) .
self::store32_le($x10) .
self::store32_le($x11) .
self::store32_le($x12) .
self::store32_le($x13) .
self::store32_le($x14) .
self::store32_le($x15);
}
/**
* @internal You should not use this directly from another application
*
* @param int $len
* @param string $nonce
* @param string $key
* @return string
* @throws SodiumException
* @throws TypeError
*/
public static function salsa20($len, $nonce, $key)
{
if (self::strlen($key) !== 32) {
throw new RangeException('Key must be 32 bytes long');
}
$kcopy = '' . $key;
$in = self::substr($nonce, 0, 8) . str_repeat("\0", 8);
$c = '';
while ($len >= 64) {
$c .= self::core_salsa20($in, $kcopy, null);
$u = 1;
// Internal counter.
for ($i = 8; $i < 16; ++$i) {
$u += self::chrToInt($in[$i]);
$in[$i] = self::intToChr($u & 0xff);
$u >>= 8;
}
$len -= 64;
}
if ($len > 0) {
$c .= self::substr(
self::core_salsa20($in, $kcopy, null),
0,
$len
);
}
try {
ParagonIE_Sodium_Compat::memzero($kcopy);
} catch (SodiumException $ex) {
$kcopy = null;
}
return $c;
}
/**
* @internal You should not use this directly from another application
*
* @param string $m
* @param string $n
* @param int $ic
* @param string $k
* @return string
* @throws SodiumException
* @throws TypeError
*/
public static function salsa20_xor_ic($m, $n, $ic, $k)
{
$mlen = self::strlen($m);
if ($mlen < 1) {
return '';
}
$kcopy = self::substr($k, 0, 32);
$in = self::substr($n, 0, 8);
// Initialize the counter
$in .= ParagonIE_Sodium_Core_Util::store64_le($ic);
$c = '';
while ($mlen >= 64) {
$block = self::core_salsa20($in, $kcopy, null);
$c .= self::xorStrings(
self::substr($m, 0, 64),
self::substr($block, 0, 64)
);
$u = 1;
for ($i = 8; $i < 16; ++$i) {
$u += self::chrToInt($in[$i]);
$in[$i] = self::intToChr($u & 0xff);
$u >>= 8;
}
$mlen -= 64;
$m = self::substr($m, 64);
}
if ($mlen) {
$block = self::core_salsa20($in, $kcopy, null);
$c .= self::xorStrings(
self::substr($m, 0, $mlen),
self::substr($block, 0, $mlen)
);
}
try {
ParagonIE_Sodium_Compat::memzero($block);
ParagonIE_Sodium_Compat::memzero($kcopy);
} catch (SodiumException $ex) {
$block = null;
$kcopy = null;
}
return $c;
}
/**
* @internal You should not use this directly from another application
*
* @param string $message
* @param string $nonce
* @param string $key
* @return string
* @throws SodiumException
* @throws TypeError
*/
public static function salsa20_xor($message, $nonce, $key)
{
return self::xorStrings(
$message,
self::salsa20(
self::strlen($message),
$nonce,
$key
)
);
}
/**
* @internal You should not use this directly from another application
*
* @param int $u
* @param int $c
* @return int
*/
public static function rotate($u, $c)
{
$u &= 0xffffffff;
$c %= 32;
return (int) (0xffffffff & (
($u << $c)
|
($u >> (32 - $c))
)
);
}
}
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