public string Crypt(string text, string key, string abc, bool encrypt)
{
Checker.KeyNull(key);
var intKey = Checker.GetKeyInt(key);
Checker.TextNull(text);
Checker.TextContain(text, abc);
// to avoid overflows
intKey %= abc.Length;
if (!encrypt)
{
intKey *= -1;
}
// otherwise invalid index
if (intKey < 0)
{
intKey += abc.Length;
}
var result = "";
foreach (var ch in text)
{
for (var j = 0; j < abc.Length; j++)
{
if (ch == abc[j])
{
var temp = (j + intKey) % abc.Length;
result += abc[temp];
break;
}
}
}
return(result);
}
