public static string DecryptMessage(string cipherText, string key)
{
cipherText = cipherText.ToUpper();
key = key.ToUpper();
char[] encryptedArray = new char[cipherText.Length];
for (int i = 0; i < cipherText.Length; i++)
{
int ci = GetCharValue(cipherText[i]);
int ki = GetCharValue(key[i % key.Length]);
int shiftedCharValue = CryptoUtilities.Mod((ci - ki), 26);
encryptedArray[i] = GetIntsCharValue(shiftedCharValue);
}
return(new string(encryptedArray));
}
public static string EncryptMessage(string plainText, string key)
{
plainText = plainText.ToUpper();
key = key.ToUpper();
char[] encryptedArray = new char[plainText.Length];
for (int i = 0; i < plainText.Length; i++)
{
int mi = GetCharValue(plainText[i]);
int ki = GetCharValue(key[i % key.Length]);
int shiftedCharValue = CryptoUtilities.Mod((mi + ki), 26);
encryptedArray[i] = GetIntsCharValue(shiftedCharValue);
}
return(new string(encryptedArray));
}