private SenderMessageKey getSenderKey(SenderKeyState senderKeyState, uint iteration)
{
SenderChainKey senderChainKey = senderKeyState.getSenderChainKey();
if (senderChainKey.getIteration() > iteration)
{
if (senderKeyState.hasSenderMessageKey(iteration))
{
return(senderKeyState.removeSenderMessageKey(iteration));
}
else
{
throw new DuplicateMessageException("Received message with old counter: " +
senderChainKey.getIteration() + " , " + iteration);
}
}
//Avoiding a uint overflow
uint senderChainKeyIteration = senderChainKey.getIteration();
if ((iteration > senderChainKeyIteration) && (iteration - senderChainKeyIteration > 2000))
{
throw new InvalidMessageException("Over 2000 messages into the future!");
}
while (senderChainKey.getIteration() < iteration)
{
senderKeyState.addSenderMessageKey(senderChainKey.getSenderMessageKey());
senderChainKey = senderChainKey.getNext();
}
senderKeyState.setSenderChainKey(senderChainKey.getNext());
return(senderChainKey.getSenderMessageKey());
}
