Ошибка с присвоением значения - C#

    class Realize
    {
        private byte G0(byte a, byte b)
        {
            return (byte)((((a + b) % 256) << 2) | (((a + b) % 256) >> 6));
        }
 
        private byte G1(byte a, byte b)
        {
            return (byte)((((a + b + 1) % 256) << 2) | (((a + b + 1) % 256) >> 6));
        }
 
        public byte[] F(byte[] x)
        {
            byte[] y = new byte[4];
            y[1] = G1((byte)(x[0] ^ x[1]), (byte)(x[2] ^ x[3]));
            y[0] = G0(x[0], y[1]);
            y[2] = G0(y[1], (byte)(x[2] ^ x[3]));
            y[3] = G1(y[2], x[3]);
            return y;
        }
 
        private void AddKeyPart(byte[] P, byte[] K)
        {
            for (int i = 0; i < 4; i++)
            {
                P[i] = (byte)(P[i] ^ K[i]);
            }
        }
 
        private byte[] XOR(byte[] a, byte[] b)
        {
            byte[] c = new byte[a.Length];
            for (int i = 0; i < c.Length; i++)
            {
                c[i] = (byte)(a[i] ^ b[i]);
            }
            return c;
        }
        public byte[] Encrypt(byte[] P, byte[][] K)
        {
            byte[] LeftPart = new byte[4];
            byte[] RightPart = new byte[4];
            Array.Copy(P, 0, LeftPart, 0, 4);
            Array.Copy(P, 4, RightPart, 0, 4);
            AddKeyPart(LeftPart, K[6]);
            AddKeyPart(RightPart, K[7]);
            byte[] Round2Left = XOR(LeftPart, RightPart);
            byte[] Round2Right = XOR(LeftPart, F(XOR(Round2Left, K[0])));
            byte[] Round3Left = Round2Right;
            byte[] Round3Right = XOR(Round2Left, F(XOR(Round2Right, K[1])));
            byte[] Round4Left = Round3Right;
            byte[] Round4Right = XOR(Round3Left, F(XOR(Round3Right, K[2])));
            byte[] Round5Left = Round4Right;
            byte[] Round5Right = XOR(Round4Left, F(XOR(Round4Right, K[3])));
            byte[] Round6Left = Round5Right;
            byte[] Round6Right = XOR(Round5Left, F(XOR(Round5Right, K[4])));
 
            byte[] CipherTextLeft = XOR(Round6Left, F(XOR(Round6Right, K[5])));
            byte[] CipherTextRight = XOR(Round6Right, CipherTextLeft);
            byte[] CipherText = new byte[8];
            Array.Copy(CipherTextLeft, 0, CipherText, 0, 4);
            Array.Copy(CipherTextRight, 0, CipherText, 4, 4);
            return CipherText;
        }
 
        public byte[] Decrypt(byte[] P, byte[][] K)
        {
            byte[] LeftPart = new byte[4];
            byte[] RightPart = new byte[4];
            Array.Copy(P, 0, LeftPart, 0, 4);
            Array.Copy(P, 4, RightPart, 0, 4);
 
            byte[] Round6Right = XOR(LeftPart, RightPart);
            byte[] Round6Left = XOR(LeftPart, F(XOR(Round6Right, K[5])));

            byte[] Round5Right = Round6Left;
            byte[] Round5Left = XOR(Round6Right, F(XOR(Round6Right, K[4])));
 
            byte[] Round4Right = Round5Left;
            byte[] Round4Left = XOR(Round5Right, F(XOR(Round5Right, K[3])));
 
            byte[] Round3Right = Round4Left;
            byte[] Round3Left = XOR(Round4Right, F(XOR(Round4Right, K[2])));
 
            byte[] Round2Right = Round3Left;
            byte[] Round2Left = XOR(Round3Right, F(XOR(Round2Right, K[1])));
 
            byte[] Round1Right = Round2Left;
            byte[] Round1Left = XOR(Round2Right, F(XOR(Round1Right, K[0])));
 
            byte[] TextLeft = Round1Left;
            byte[] TextRight = XOR(Round1Left, Round1Right);
            AddKeyPart(TextLeft, K[6]);
            AddKeyPart(TextRight, K[7]);
            byte[] Text = new byte[8];
            Array.Copy(TextLeft, 0, Text, 0, 4);
            Array.Copy(TextRight, 0, Text, 4, 4);
            return Text;
        }
    }

 class Program
    {
        static void Main(string[] args)
        {
            byte[] x = new byte[8];
            for(int i = 0; i < 8; i++)
                x[i] = byte.Parse(Console.ReadLine());
            Console.WriteLine();
            byte[][] y = new byte[8][];// как присвоить значение???
 
            Realize real = new Realize();
            Console.WriteLine(real.Encrypt(x, y));
            Console.ReadKey();
        }
 
    }