[C#]PolyCloud Encryption - Byte[] Included!

Code:

public class PolyCloud
{
#region "Static Functions"

public static string EncryptData(string Input, string Key)
{
return Convert.ToBase64String(EncryptData(System.Text.Encoding.UTF8.GetBytes(Input),
System.Text.Encoding.UTF8.GetBytes(Key)));
}

public static byte[] EncryptData(byte[] Input, byte[] Key)
{
Random Rnd = new Random();
int Salt = Rnd.Next(1, 50);
byte[] FinVal = new byte[Input.Length + 1];
FinVal[Input.Length] = (byte)Salt;
short kc = 0;
for (int index = 0; index < Input.Length; index++)
{
if (kc >= Key.Length)
kc = 0;
FinVal[index] = Convert.ToByte(Input[index] + (Input.Length % Key.Length) + (Key[kc]) - Salt);
kc++;
}
return FinVal;
}

public static string DecryptData(string Input, string Key)
{
return System.Text.Encoding.UTF8.GetString(DecryptData(Convert.FromBase64String(Input),
System.Text.Encoding.UTF8.GetBytes(Key)));
}

public static byte[] DecryptData(byte[] Input, byte[] Key)
{
int Salt = (int)Input[Input.Length - 1];
byte[] FinVal = new byte[Input.Length - 1];
short kc = 0;
for (int index = 0; index < Input.Length - 1; index++)
{
if (kc >= Key.Length)
kc = 0;
if (index >= Input.Length - 1)
continue;
FinVal[index] = Convert.ToByte(Input[index] - (FinVal.Length % Key.Length) - (Key[kc]) + Salt);
kc++;
}
return FinVal;
}
#endregion
}