public static string Encrypt(string text, PublicKey key)
{
var generator = new BbsGenerator(key.N);
var result = new StringBuilder();
foreach (var c in text)
{
var b = generator.GetNext();
var t = c;
result.Append((char)(t ^ b));
}
generator.GetNext();
result.Append($"#{generator.X}");
return(result.ToString());
}
public static string Decrypt(string encryptedText, Key key, int length)
{
var seed = GetLastSeed(encryptedText);
var x0 = RestoreX0(key, length, seed);
Console.WriteLine($"Restored x0={x0}");
var generator = new BbsGenerator(key.PublicKey.N, x0);
var result = new StringBuilder();
for (var i = 0; i < length; i++)
{
var b = generator.GetNext();
var t = encryptedText[i];
result.Append((char)(t ^ b));
}
return(result.ToString());
}