A General Framework for Guess-and-Determine and Time-Memory-Data Trade-Off Attacks on Stream Ciphers

In this paper, we present a framework for guess-and-determine attack on stream ciphers that relies on guessing part of the internal state and solving for the remaining unknown cipher state based on known keystream bits. We show that this basic attack can always be extended to a Time-Memory-Data (TMD) Trade-Off attack. This allows us to easily extend any guess-and-determine attack to a guess-and-determine TMD attack, which improves the online attack at the expense of memory, pre-processing time, and data requirement. Lastly, we illustrate three applications of the attack framework.