TY - GEN
T1 - A new attack on 6-round IDEA
AU - Biham, Eli
AU - Dunkelman, Orr
AU - Keller, Nathan
PY - 2007
Y1 - 2007
N2 - IDEA is a 64-bit block cipher with 128-bit keys introduced by Lai and Massey in 1991. IDEA is one of the most widely used block ciphers, due to its inclusion in several cryptographic packages, such as PGP. Since its introduction in 1991, IDEA has withstood extensive cryptanalytic effort, but no attack was found on the full (8.5-round) variant of the cipher. In this paper we present the first known attack on 6-round IDEA faster than exhaustive key search. The attack exploits the weak key-schedule algorithm of IDEA, and combines Square-like techniques with linear cryptanalysis to increase the number of rounds that can be attacked. The attack is the best known attack on IDEA. We also improve previous attacks on 5-round IDEA and introduce a 5-round attack which uses only 16 known plaintexts.
AB - IDEA is a 64-bit block cipher with 128-bit keys introduced by Lai and Massey in 1991. IDEA is one of the most widely used block ciphers, due to its inclusion in several cryptographic packages, such as PGP. Since its introduction in 1991, IDEA has withstood extensive cryptanalytic effort, but no attack was found on the full (8.5-round) variant of the cipher. In this paper we present the first known attack on 6-round IDEA faster than exhaustive key search. The attack exploits the weak key-schedule algorithm of IDEA, and combines Square-like techniques with linear cryptanalysis to increase the number of rounds that can be attacked. The attack is the best known attack on IDEA. We also improve previous attacks on 5-round IDEA and introduce a 5-round attack which uses only 16 known plaintexts.
UR - http://www.scopus.com/inward/record.url?scp=38149109256&partnerID=8YFLogxK
U2 - 10.1007/978-3-540-74619-5_14
DO - 10.1007/978-3-540-74619-5_14
M3 - Conference contribution
AN - SCOPUS:38149109256
SN - 354074617X
SN - 9783540746171
T3 - Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
SP - 211
EP - 224
BT - Fast Software Encryption - 14th International Workshop, FSE 2007
PB - Springer Verlag
T2 - 14th International Workshop on Fast Software Encryption, FSE 2007
Y2 - 26 March 2007 through 28 March 2007
ER -