public override string Decriptare(string textCriptat) { string textClar = ""; for (int i = 0; i < textCriptat.Length; i++) { if (!char.IsLetter(textCriptat[i])) { textClar += textCriptat[i]; } else { char linie = key[i % key.Length]; char original = Util.ShiftLetter(textCriptat[i], -(linie - 'a')); if (Util.IsUpperCase(textCriptat[i])) { textClar += char.ToUpper(original); } else { textClar += original; } } } return(textClar); }