ParagonIE_Sodium_Core_ChaCha20

10class ParagonIE_Sodium_Core_ChaCha20 extends ParagonIE_Sodium_Core_Util11{12    /**13     * Bitwise left rotation14     *15     * @internal You should not use this directly from another application16     *17     * @param int $v18     * @param int $n19     * @return int20     */21    public static function rotate($v, $n)22    {23        $v &= 0xffffffff;24        $n &= 31;25        return (int) (26            0xffffffff & (27                ($v << $n)28                    |29                ($v >> (32 - $n))30            )31        );32    }33 34    /**35     * The ChaCha20 quarter round function. Works on four 32-bit integers.36     *37     * @internal You should not use this directly from another application38     *39     * @param int $a40     * @param int $b41     * @param int $c42     * @param int $d43     * @return array<int, int>44     */45    protected static function quarterRound($a, $b, $c, $d)46    {47        # a = PLUS(a,b); d = ROTATE(XOR(d,a),16);48        /** @var int $a */49        $a = ($a + $b) & 0xffffffff;50        $d = self::rotate($d ^ $a, 16);51 52        # c = PLUS(c,d); b = ROTATE(XOR(b,c),12);53        /** @var int $c */54        $c = ($c + $d) & 0xffffffff;55        $b = self::rotate($b ^ $c, 12);56 57        # a = PLUS(a,b); d = ROTATE(XOR(d,a), 8);58        /** @var int $a */59        $a = ($a + $b) & 0xffffffff;60        $d = self::rotate($d ^ $a, 8);61 62        # c = PLUS(c,d); b = ROTATE(XOR(b,c), 7);63        /** @var int $c */64        $c = ($c + $d) & 0xffffffff;65        $b = self::rotate($b ^ $c, 7);66        return array((int) $a, (int) $b, (int) $c, (int) $d);67    }68 69    /**70     * @internal You should not use this directly from another application71     *72     * @param ParagonIE_Sodium_Core_ChaCha20_Ctx $ctx73     * @param string $message74     *75     * @return string76     * @throws TypeError77     * @throws SodiumException78     */79    public static function encryptBytes(80        ParagonIE_Sodium_Core_ChaCha20_Ctx $ctx,81        $message = ''82    ) {83        $bytes = self::strlen($message);84 85        /*86        j0 = ctx->input[0];87        j1 = ctx->input[1];88        j2 = ctx->input[2];89        j3 = ctx->input[3];