private static string Cipher(string key, string str, ShiftMethod shiftMethod)
{
var encryptedText = "";
var keyIndex = 0;
foreach (var symbol in str)
{
if (!Alphabet.Contains(symbol.ToString()))
{
encryptedText += symbol;
continue;
}
var shiftedIndex = shiftMethod(key[keyIndex], symbol);
keyIndex++;
if (keyIndex == key.Length)
{
keyIndex = 0;
}
if (char.IsUpper(symbol))
{
encryptedText += char.ToUpper(Alphabet[shiftedIndex]);
}
else
{
encryptedText += Alphabet[shiftedIndex];
}
}
return(encryptedText);
}
public string Encrypt(string key, string str)
{
ShiftMethod shiftMethod = CalculateShiftForEncryption;
return(Cipher(key, str, shiftMethod));
}