International Conference on Cryptology and Information Security in Latin America

LATINCRYPT 2015: Progress in Cryptology -- LATINCRYPT 2015 pp 170-186

Cryptanalysis of the Full 8.5-Round REESSE3+ Block Cipher

Conference paper

DOI: 10.1007/978-3-319-22174-8_10

Volume 9230 of the book series Lecture Notes in Computer Science (LNCS)
Cite this paper as:
Nakahara J. (2015) Cryptanalysis of the Full 8.5-Round REESSE3+ Block Cipher. In: Lauter K., Rodríguez-Henríquez F. (eds) Progress in Cryptology -- LATINCRYPT 2015. LATINCRYPT 2015. Lecture Notes in Computer Science, vol 9230. Springer, Cham


This paper describes the first independent cryptanalysis of the full 8.5-round REESSE3+ block cipher, a large-block variant of the IDEA cipher. We show that large classes of weak keys exist in REESSE3+, just like in IDEA, under differential and linear attacks. Moreover, doubling the number of rounds is not enough to avoid weak keys. The existence of weak keys jeopardizes the use of REESSE3+ as a building block in the construction of other cryptographic primitives such as hash functions in modes such as Davies-Meyer’s. We also describe square and impossible differential attacks on reduced-round versions.


CryptanalysisIDEAWeak keysBlock cipher design

Copyright information

© Springer International Publishing Switzerland 2015

Authors and Affiliations

  1. 1.Jose Benedito de Moraes LemeSao PauloBrazil