Lecture Notes in Computer Science vol:2887 pages:111-128
FSE 2003 date:February 24-26, 2003
SOBER-t32 is a candidate stream cipher in the NESSIE competition. Some new attacks are presented in this paper. A Guess and Determine attack is mounted against SOBER-t32 without the decimation of the key stream by the so-called stuttering phase. Also, two distinguishing attacks are mounted against full SOBER-t32. These attacks are not practically feasible, but they are theoretically more efficient than exhaustive key search.