Long Wen

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LBlock is a 32-round lightweight block cipher with 64-bit block size and 80-bit key. This paper identifies 16-round related-key impossible differentials of LBlock, which are better than the 15-round related-key impossible differentials used in the previous attack. Based on these 16-round related-key impossible differentials, we can attack 23 rounds of(More)
Group decision-making (GD) is a fuzzy problem with high complexity and is difficult for us to handle. Usually the rule-based Group Decision-making Support System (GDSS) is used to solve the GD problem. But the definitions of the fuzzy rules and membership functions in GDSS are generally affected by subjective decision. So the rationality of GDSS is(More)
In this paper, we reveal a fundamental property of block ciphers: There can exist linear approximations such that their biases ε are deterministically invariant under key difference. This behaviour is highly unlikely to occur in idealized ciphers but persists, for instance, in 5-round AES. Interestingly, the property of key difference invariant bias is(More)
A main contribution of this paper is an improved analysis against HMAC instantiating with reduced Whirlpool. It recovers equivalent keys, which are often denoted as Kin and Kout, of HMAC with 7-round Whirlpool, while the previous best attack can work only for 6 rounds. Our approach is applying the meet-in-the-middle (MITM) attack on AES to recover MAC keys(More)