TY - GEN
T1 - The optimal key estimation of stream ciphers and its approximation algorithm based on a probabilistic inference
AU - Iikubo, Yuji
AU - Horii, Shunsuke
AU - Matsushima, Toshiyasu
PY - 2012/12/1
Y1 - 2012/12/1
N2 - A stream cipher is an important class of encryption algorithms. Its safety depends on the structure of the pseudorandom number generator used. There are various types of pseudo-random number generators in existence, and attack algorithms used on them have been studied individually. In this paper, we express the problem of attacks on a general stream cipher as a probabilistic inference problem, and formulate the optimal key estimation. We also propose a unified framework of attack algorithms that can be applied to a wide variety of stream ciphers. The optimal key estimation, however, has computational complexity. To reduce the complexity, an approximation algorithm based on a probabilistic inference is proposed. We also describe some attack algorithms used on practical pseudorandom number generators. Finally, the proposed algorithm is evaluated by through a computer simulation.
AB - A stream cipher is an important class of encryption algorithms. Its safety depends on the structure of the pseudorandom number generator used. There are various types of pseudo-random number generators in existence, and attack algorithms used on them have been studied individually. In this paper, we express the problem of attacks on a general stream cipher as a probabilistic inference problem, and formulate the optimal key estimation. We also propose a unified framework of attack algorithms that can be applied to a wide variety of stream ciphers. The optimal key estimation, however, has computational complexity. To reduce the complexity, an approximation algorithm based on a probabilistic inference is proposed. We also describe some attack algorithms used on practical pseudorandom number generators. Finally, the proposed algorithm is evaluated by through a computer simulation.
UR - http://www.scopus.com/inward/record.url?scp=84873548587&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84873548587&partnerID=8YFLogxK
M3 - Conference contribution
AN - SCOPUS:84873548587
SN - 9784885522673
T3 - 2012 International Symposium on Information Theory and Its Applications, ISITA 2012
SP - 531
EP - 535
BT - 2012 International Symposium on Information Theory and Its Applications, ISITA 2012
T2 - 2012 International Symposium on Information Theory and Its Applications, ISITA 2012
Y2 - 28 October 2012 through 31 October 2012
ER -