ParagonIE_Sodium_Core32_ChaCha20_Ctx

10class ParagonIE_Sodium_Core32_ChaCha20_Ctx extends ParagonIE_Sodium_Core32_Util implements ArrayAccess11{12    /**13     * @var SplFixedArray internally, <int, ParagonIE_Sodium_Core32_Int32>14     */15    protected $container;16 17    /**18     * ParagonIE_Sodium_Core_ChaCha20_Ctx constructor.19     *20     * @internal You should not use this directly from another application21     *22     * @param string $key     ChaCha20 key.23     * @param string $iv      Initialization Vector (a.k.a. nonce).24     * @param string $counter The initial counter value.25     *                        Defaults to 8 0x00 bytes.26     * @throws InvalidArgumentException27     * @throws SodiumException28     * @throws TypeError29     */30    public function __construct($key = '', $iv = '', $counter = '')31    {32        if (self::strlen($key) !== 32) {33            throw new InvalidArgumentException('ChaCha20 expects a 256-bit key.');34        }35        if (self::strlen($iv) !== 8) {36            throw new InvalidArgumentException('ChaCha20 expects a 64-bit nonce.');37        }38        $this->container = new SplFixedArray(16);39 40        /* "expand 32-byte k" as per ChaCha20 spec */41        $this->container[0]  = new ParagonIE_Sodium_Core32_Int32(array(0x6170, 0x7865));42        $this->container[1]  = new ParagonIE_Sodium_Core32_Int32(array(0x3320, 0x646e));43        $this->container[2]  = new ParagonIE_Sodium_Core32_Int32(array(0x7962, 0x2d32));44        $this->container[3]  = new ParagonIE_Sodium_Core32_Int32(array(0x6b20, 0x6574));45 46        $this->container[4]  = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 0, 4));47        $this->container[5]  = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 4, 4));48        $this->container[6]  = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 8, 4));49        $this->container[7]  = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 12, 4));50        $this->container[8]  = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 16, 4));51        $this->container[9]  = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 20, 4));52        $this->container[10] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 24, 4));53        $this->container[11] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 28, 4));54 55        if (empty($counter)) {56            $this->container[12] = new ParagonIE_Sodium_Core32_Int32();57            $this->container[13] = new ParagonIE_Sodium_Core32_Int32();58        } else {59            $this->container[12] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($counter, 0, 4));60            $this->container[13] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($counter, 4, 4));61        }62        $this->container[14] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($iv, 0, 4));63        $this->container[15] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($iv, 4, 4));64    }65 66    /**67     * @internal You should not use this directly from another application68     *69     * @param int $offset70     * @param int|ParagonIE_Sodium_Core32_Int32 $value71     * @return void72     */73    #[ReturnTypeWillChange]74    public function offsetSet($offset, $value)75    {76        if (!is_int($offset)) {77            throw new InvalidArgumentException('Expected an integer');78        }79        if ($value instanceof ParagonIE_Sodium_Core32_Int32) {80            /*81        } elseif (is_int($value)) {82            $value = ParagonIE_Sodium_Core32_Int32::fromInt($value);83            */84        } else {85            throw new InvalidArgumentException('Expected an integer');86        }87        $this->container[$offset] = $value;88    }89