IACR News item: 11 November 2012
Gaoli Wang, Yanzhao Shen
ePrint ReportThis paper studies the security of SM3 hash function against preimage attack and pseudo-collision attack. We propose preimage attacks on 29-step and 30-step SM3, and pseudo-preimage attacks on 31-step and 32-step SM3 out of 64 steps. The complexities of these attacks are $2^{245}$ 29-step operations, $2^{251.1}$ 30-step operations, $2^{245}$ 31-step operations and $2^{251.1}$ 32-step operations, respectively. These (pseudo) preimage attacks are all from the first step of the reduced SM3. Meanwhile, these (pseudo) preimage attacks can be converted into pseudo-collision attacks on SM3 reduced to 29 steps, 30 steps, 31 steps and 32 steps with complexities of $2^{122}$, $2^{125.1}$, $2^{122}$ and $2^{125.1}$ respectively. As far as we know, the previously best known preimage attacks on SM3 cover 28 steps (from the first step) and 30 steps (from the 7-th step), and there is no publicly published result on (pseudo) collision attack on SM3.
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