Renci.SshNet.Security.Cryptography.Ciphers.Arc4Cipher.ProcessBytes C# (CSharp) Method

        private int ProcessBytes(byte[] inputBuffer, int inputOffset, int inputCount, byte[] outputBuffer, int outputOffset)
        {
            if ((inputOffset + inputCount) > inputBuffer.Length)
            {
                throw new IndexOutOfRangeException("input buffer too short");
            }

            if ((outputOffset + inputCount) > outputBuffer.Length)
            {
                throw new IndexOutOfRangeException("output buffer too short");
            }

            for (var i = 0; i < inputCount; i++)
            {
                _x = (_x + 1) & 0xff;
                _y = (_engineState[_x] + _y) & 0xff;

                // swap
                var tmp = _engineState[_x];
                _engineState[_x] = _engineState[_y];
                _engineState[_y] = tmp;

                // xor
                outputBuffer[i + outputOffset] = (byte)(inputBuffer[i + inputOffset] ^ _engineState[(_engineState[_x] + _engineState[_y]) & 0xff]);
            }
            return inputCount;
        }