Results Announcement: N. Ferguson, , "Upper Bounds on Differential Characteristics in Twofish," Twofish Technical Report #1, Counterpane Systems, Aug 1998. Abstract: In our initial paper the Twofish block cipher was introduced, and initial estimates of an upper bounds on the probability of a 12-round differential were given. These results used an imperfect model of Twofish. We present an improved model, and show that any 12-round differential characteristic has a probability of at most $2^{-102.8}$. This paper is available at http://www.counterpane.com/twofish.html, and will be made available at the AES Workshop next week. Cheers, Bruce ********************************************************************** Bruce Schneier, President, Counterpane Systems Phone: 612-823-1098 101 E Minnehaha Parkway, Minneapolis, MN 55419 Fax: 612-823-1590 Free crypto newsletter. See: http://www.counterpane.com