Kexin Qiao

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Outline p Differential cryptanalysis [Biham, Shamir, 1991] is one of the most powerful attacks on block ciphers p Finding a good differential characteristic with high probability is the first step in the (related-key) differential attack Motivation
In this paper, we investigate the Mixed-integer Linear Programming (MILP) modelling of the differential and linear behavior of a wide range of block ciphers. We point out that the differential behavior of an arbitrary S-box can be exactly described by a small system of linear inequalities. Based on this observation and MILP technique, we propose an(More)
密码算法的不同部件具有相同输入时的线性逼近的相关度计算不能应用堆积引理, 其计算是一个对线性分析结果有重要影响的难题。 充分考虑了 SIMON 分组密码算法不同运算的相关性, 通过化标准二次型的方法准确计算了轮函数线性逼近的相关度, 得到精确的线性分析结果。 基于混合整数线性规划建模, 找到了 SIMON 算法的多个版本的更好的线性迹和线性闭包, 给出了 SIMON 的更好的密钥恢复攻击结果。
In this paper, we present an invariant subspace attack against block cipher Midori64 which has recently been proposed by Banik et al. at Asiacrypt 2015 to achieve low energy consumption. We show that when each nibble of the key has the value 0 or 1 and each nibble of the plaintext has the value 8 or 9, each nibble of the ciphertext also has the value 8 or 9(More)
In IACR ePrint 2014/747, a method for constructing mixed-integer linear programming (MILP) models whose feasible regions are exactly the sets of all possible differential (or linear) characteristics for a wide range of block ciphers is presented. These models can be used to search for or enumerate differential and linear characteristics of a block cipher(More)
The Simeck family of lightweight block ciphers was proposed in CHES 2015 which combines the good design components from NSA designed ciphers SIMON and SPECK. Dynamic key-guessing techniques were proposed by Wang et al. to greatly reduce the key space guessed in differential cryptanalysis and work well on SIMON. In this paper, we implement the dynamic(More)
In CRYPTO 2014 Albrecht et al. brought in a 20-round iterative lightweight block cipher PRIDE which is based on a good linear layer for achieving a tradeoff between security and efficiency. A recent analysis is presented by Zhao et al.. Inspired by their work, we use an automatic search method to find out 56 iterative differential characteristics of PRIDE,(More)