International Association for Cryptologic Research

International Association
for Cryptologic Research

CryptoDB

Jun Yajima

Affiliation: FUJITSU LABORATORIES LTD.

Publications

Year
Venue
Title
2008
CHES
2006
ASIACRYPT
2006
EPRINT
Message Modification for Step 21-23 on SHA-0
In CRYPTO 2005, Xiaoyun Wang, Hongbo Yu and Yiqun Lisa Yin proposed an efficient collision attack on SHA-0. Collision messages are found with complexity $2^{39}$ SHA-0 operations by using their method. Collision messages can be obtained when a message satisfying all sufficient conditions is found. In their paper, they proposed message modifications that can satisfy all sufficient conditions of step 1-20. However, they didn't propose message modifications for sufficient conditions after step 21. In this paper, we propose message modifications for sufficient conditions of step 21-23. By using our message modifications, collision messages are found with complexity $2^{36}$ SHA-0 operations.
2006
EPRINT
How to Construct Sufficient Condition in Searching Collisions of MD5
In Eurocrypt 2005, Wang et al. presented a collision attak on MD5. In their paper, they intoduced gSufficient Conditionh which would be needed to generate collisions. In this paper, we explain how to construct sufficent conditions of MD5 when a differential path is given. By applying our algorithm to a collision path given byWang et al, we found that sufficient conditions introduced by them contained some unnecessary conditions. Generally speaking, when a differential path is given, corresponding sets of sufficient conditions is not unique. In our research, we analyzed the differential path found by Wang et al, and we found a different set of sufficient conditions from that of Wang et al. We have generated collisions by using our sifficient conditions.
2005
EPRINT
Wang's sufficient conditions of MD5 are not sufficient
Jun Yajima Takeshi Shimoyama
In this paper, we report that the "sufficient conditions" of MD5 of the modification technique for the collision search algorithm described by Wang are not sufficient. In our analysis, we show at least 4 extra-conditions for the message modification in the first block and corrections of the several conditions which are correspond to the highest (32nd) bit of the sufficient conditions in the second block should be needed. And we show the new collision message which is completely different from the message pairs showed by Wang by using our extended sufficient conditions.
2002
CHES
2001
FSE