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)); }