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针对SOSEMANUK流密码已有攻击方法复杂度过高的不足,提出并讨论了一种基于故障信息的猜测确定攻击方法.首先利用代数方法构建密码在比特层面的等效代数方程组,然后向密码注入随机单字故障,在深入分析故障传播特征的基础上,将故障信息表示成代数方程组并猜测密码部分内部状态,使用CryptoMinisat解析器求解代数方程组恢复密码初始内部状态.实验结果表明:对密码首轮加密进行攻击,恢复密码全部初始内部状态所需的故障注入次数为20次,计算复杂度为O(296),对密码前两轮加密进行攻击,无须猜测密码内部状态,仅注入10个单字故障即可恢复密码全部初始内部状态.与已有结果相比,新方法攻击复杂度显著降低.
Aiming at the shortcomings of the complexity of SOSEMANUK stream cipher method, this paper proposes and discusses a guessing attack method based on fault information.Firstly, algebraic method is used to construct equivalent algebraic equations with cipher at bit level, Based on the in-depth analysis of fault propagation characteristics, the fault information is expressed as algebraic equations and guessed the internal state of the cipher, and the CryptoMinisat resolver is used to solve the initial state of the cipher. The experimental results show that: Rounds of encryption to attack and restore the initial internal state of the password required for the number of fault injection 20 times, the computational complexity of O (296), the first two rounds of encryption attacks to attack, no need to guess the internal state of the password, only inject 10 words Failure to recover the entire initial internal state of the password.Compared with the existing results, the attack complexity of the new method is significantly reduced.