private static string DecryptPart(string header, MonthlySettings monSet, string[] groups, string[,] digraphs)
{
string[] headerTokens = header.Split(new string[] { " " }, StringSplitOptions.RemoveEmptyEntries);
string[] timestampTokens = headerTokens[1].Split(new string[] { "/" }, StringSplitOptions.RemoveEmptyEntries);
int day = int.Parse(timestampTokens[1]);
Settings settings = monSet.DailySettings.FirstOrDefault(s => s.Day == day);
string indicator1 = groups[0];
string indicator2 = groups[1];
string cipherText = string.Concat(groups.Skip(2).Take(groups.Length - 4));
string messageKey, startPosition;
DecryptDigraphs(indicator1, indicator2, digraphs, out startPosition, out messageKey);
if (settings.Grund.Length == 3)
{
string trimmedStart = startPosition.Substring(1, 3);
string trimmedKey = messageKey.Substring(0, 3);
Enigma.Message msg = new Enigma.Message(settings);
string actualStart = msg.Encrypt(trimmedKey, trimmedStart);
return(msg.Decrypt(cipherText, actualStart));
}
else
{
Enigma.Message msg = new Enigma.Message(settings);
string actualStart = msg.Encrypt(messageKey, startPosition);
return(msg.Decrypt(cipherText, actualStart));
}
}
private static string DecryptPart(string header, string[] groups, MonthlySettings settings)
{
string[] headerTokens = header.Split(new string[] { "=" }, StringSplitOptions.RemoveEmptyEntries);
string last = headerTokens.Last().Trim();
string[] messageRotorSettings = last.Split(new string[] { " " }, StringSplitOptions.RemoveEmptyEntries);
string rotorPos = messageRotorSettings[0];
string indicator = messageRotorSettings[1];
Settings partSettings = GetSettingsByKenngruppen(settings, groups[0]);
Enigma.Message msg = new Enigma.Message(partSettings);
string msgKey = msg.Encrypt(indicator, rotorPos);
string partBody = string.Concat(groups.Skip(1).Take(groups.Length - 1));
return(msg.Decrypt(partBody, msgKey));
}
