ParagonIE_Sodium_Core_HSalsa20

10abstract class ParagonIE_Sodium_Core_HSalsa20 extends ParagonIE_Sodium_Core_Salsa2011{12    /**13     * Calculate an hsalsa20 hash of a single block14     *15     * HSalsa20 doesn't have a counter and will never be used for more than16     * one block (used to derive a subkey for xsalsa20).17     *18     * @internal You should not use this directly from another application19     *20     * @param string $in21     * @param string $k22     * @param string|null $c23     * @return string24     * @throws TypeError25     */26    public static function hsalsa20($in, $k, $c = null)27    {28        if ($c === null) {29            $x0  = 0x61707865;30            $x5  = 0x3320646e;31            $x10 = 0x79622d32;32            $x15 = 0x6b206574;33        } else {34            $x0  = self::load_4(self::substr($c, 0, 4));35            $x5  = self::load_4(self::substr($c, 4, 4));36            $x10 = self::load_4(self::substr($c, 8, 4));37            $x15 = self::load_4(self::substr($c, 12, 4));38        }39        $x1  = self::load_4(self::substr($k, 0, 4));40        $x2  = self::load_4(self::substr($k, 4, 4));41        $x3  = self::load_4(self::substr($k, 8, 4));42        $x4  = self::load_4(self::substr($k, 12, 4));43        $x11 = self::load_4(self::substr($k, 16, 4));44        $x12 = self::load_4(self::substr($k, 20, 4));45        $x13 = self::load_4(self::substr($k, 24, 4));46        $x14 = self::load_4(self::substr($k, 28, 4));47        $x6  = self::load_4(self::substr($in, 0, 4));48        $x7  = self::load_4(self::substr($in, 4, 4));49        $x8  = self::load_4(self::substr($in, 8, 4));50        $x9  = self::load_4(self::substr($in, 12, 4));51 52        for ($i = self::ROUNDS; $i > 0; $i -= 2) {53            $x4 ^= self::rotate($x0 + $x12, 7);54            $x8 ^= self::rotate($x4 + $x0, 9);55            $x12 ^= self::rotate($x8 + $x4, 13);56            $x0 ^= self::rotate($x12 + $x8, 18);57            $x9 ^= self::rotate($x5 + $x1, 7);58            $x13 ^= self::rotate($x9 + $x5, 9);59            $x1 ^= self::rotate($x13 + $x9, 13);60            $x5 ^= self::rotate($x1 + $x13, 18);61            $x14 ^= self::rotate($x10 + $x6, 7);62            $x2 ^= self::rotate($x14 + $x10, 9);63            $x6 ^= self::rotate($x2 + $x14, 13);64            $x10 ^= self::rotate($x6 + $x2, 18);65            $x3 ^= self::rotate($x15 + $x11, 7);66            $x7 ^= self::rotate($x3 + $x15, 9);67            $x11 ^= self::rotate($x7 + $x3, 13);68            $x15 ^= self::rotate($x11 + $x7, 18);69            $x1 ^= self::rotate($x0 + $x3, 7);70            $x2 ^= self::rotate($x1 + $x0, 9);71            $x3 ^= self::rotate($x2 + $x1, 13);72            $x0 ^= self::rotate($x3 + $x2, 18);73            $x6 ^= self::rotate($x5 + $x4, 7);74            $x7 ^= self::rotate($x6 + $x5, 9);75            $x4 ^= self::rotate($x7 + $x6, 13);76            $x5 ^= self::rotate($x4 + $x7, 18);77            $x11 ^= self::rotate($x10 + $x9, 7);78            $x8 ^= self::rotate($x11 + $x10, 9);79            $x9 ^= self::rotate($x8 + $x11, 13);80            $x10 ^= self::rotate($x9 + $x8, 18);81            $x12 ^= self::rotate($x15 + $x14, 7);82            $x13 ^= self::rotate($x12 + $x15, 9);83            $x14 ^= self::rotate($x13 + $x12, 13);84            $x15 ^= self::rotate($x14 + $x13, 18);85        }86 87        return self::store32_le($x0) .88            self::store32_le($x5) .89            self::store32_le($x10) .