Another attack on A5/1

P. Ekdahl, T. Johansson
2003 IEEE Transactions on Information Theory  
A5/1 is a stream cipher used in the GSM standard. Several time-memory trade-off attacks against A5/1 have been proposed, most notably the recent attack by Biryukov, Shamir and Wagner, which can break A5/1 in seconds using huge precomputation time and memory. This paper presents a completely different attack on A5/1, based on ideas from correlation attacks. Whereas time-memory trade-off attacks have a complexity which is exponential with the shift register length, the complexity of the proposed
more » ... ttack is almost independent of the shift register length. Our implementation of the suggested attack breaks A5/1 in a few minutes using 2-5 minutes of conversation plaintext.
doi:10.1109/tit.2002.806129 fatcat:mqipvv4ibvgoxp4fpcmfyt36au