private byte[] decrypt(SessionRecord sessionRecord, WhisperMessage ciphertext)
{
lock (SESSION_LOCK)
{
IEnumerator<SessionState> previousStates = sessionRecord.getPreviousSessionStates().GetEnumerator(); //iterator
LinkedList<Exception> exceptions = new LinkedList<Exception>();
try
{
SessionState sessionState = new SessionState(sessionRecord.getSessionState());
byte[] plaintext = decrypt(sessionState, ciphertext);
sessionRecord.setState(sessionState);
return plaintext;
}
catch (InvalidMessageException e)
{
exceptions.AddLast(e); // add (java default behavioir addlast)
}
while (previousStates.MoveNext()) //hasNext();
{
try
{
SessionState promotedState = new SessionState(previousStates.Current); //.next()
byte[] plaintext = decrypt(promotedState, ciphertext);
sessionRecord.getPreviousSessionStates().Remove(previousStates.Current); // previousStates.remove()
sessionRecord.promoteState(promotedState);
return plaintext;
}
catch (InvalidMessageException e)
{
exceptions.AddLast(e);
}
}
throw new InvalidMessageException("No valid sessions.", exceptions);
}
}
