ParagonIE_Sodium_Core_Salsa20

10abstract class ParagonIE_Sodium_Core_Salsa20 extends ParagonIE_Sodium_Core_Util11{12    const ROUNDS = 20;13 14    /**15     * Calculate an salsa20 hash of a single block16     *17     * @internal You should not use this directly from another application18     *19     * @param string $in20     * @param string $k21     * @param string|null $c22     * @return string23     * @throws TypeError24     */25    public static function core_salsa20($in, $k, $c = null)26    {27        if (self::strlen($k) < 32) {28            throw new RangeException('Key must be 32 bytes long');29        }30        if ($c === null) {31            $j0  = $x0  = 0x61707865;32            $j5  = $x5  = 0x3320646e;33            $j10 = $x10 = 0x79622d32;34            $j15 = $x15 = 0x6b206574;35        } else {36            $j0  = $x0  = self::load_4(self::substr($c, 0, 4));37            $j5  = $x5  = self::load_4(self::substr($c, 4, 4));38            $j10 = $x10 = self::load_4(self::substr($c, 8, 4));39            $j15 = $x15 = self::load_4(self::substr($c, 12, 4));40        }41        $j1  = $x1  = self::load_4(self::substr($k, 0, 4));42        $j2  = $x2  = self::load_4(self::substr($k, 4, 4));43        $j3  = $x3  = self::load_4(self::substr($k, 8, 4));44        $j4  = $x4  = self::load_4(self::substr($k, 12, 4));45        $j6  = $x6  = self::load_4(self::substr($in, 0, 4));46        $j7  = $x7  = self::load_4(self::substr($in, 4, 4));47        $j8  = $x8  = self::load_4(self::substr($in, 8, 4));48        $j9  = $x9  = self::load_4(self::substr($in, 12, 4));49        $j11 = $x11 = self::load_4(self::substr($k, 16, 4));50        $j12 = $x12 = self::load_4(self::substr($k, 20, 4));51        $j13 = $x13 = self::load_4(self::substr($k, 24, 4));52        $j14 = $x14 = self::load_4(self::substr($k, 28, 4));53 54        for ($i = self::ROUNDS; $i > 0; $i -= 2) {55            $x4 ^= self::rotate($x0 + $x12, 7);56            $x8 ^= self::rotate($x4 + $x0, 9);57            $x12 ^= self::rotate($x8 + $x4, 13);58            $x0 ^= self::rotate($x12 + $x8, 18);59 60            $x9 ^= self::rotate($x5 + $x1, 7);61            $x13 ^= self::rotate($x9 + $x5, 9);62            $x1 ^= self::rotate($x13 + $x9, 13);63            $x5 ^= self::rotate($x1 + $x13, 18);64 65            $x14 ^= self::rotate($x10 + $x6, 7);66            $x2 ^= self::rotate($x14 + $x10, 9);67            $x6 ^= self::rotate($x2 + $x14, 13);68            $x10 ^= self::rotate($x6 + $x2, 18);69 70            $x3 ^= self::rotate($x15 + $x11, 7);71            $x7 ^= self::rotate($x3 + $x15, 9);72            $x11 ^= self::rotate($x7 + $x3, 13);73            $x15 ^= self::rotate($x11 + $x7, 18);74 75            $x1 ^= self::rotate($x0 + $x3, 7);76            $x2 ^= self::rotate($x1 + $x0, 9);77            $x3 ^= self::rotate($x2 + $x1, 13);78            $x0 ^= self::rotate($x3 + $x2, 18);79 80            $x6 ^= self::rotate($x5 + $x4, 7);81            $x7 ^= self::rotate($x6 + $x5, 9);82            $x4 ^= self::rotate($x7 + $x6, 13);83            $x5 ^= self::rotate($x4 + $x7, 18);84 85            $x11 ^= self::rotate($x10 + $x9, 7);86            $x8 ^= self::rotate($x11 + $x10, 9);87            $x9 ^= self::rotate($x8 + $x11, 13);88            $x10 ^= self::rotate($x9 + $x8, 18);89