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Arnold映射Hash加密算法是一种二维混沌系统与hash函数相结合的加密方法,一般以Arnold映射的初值、迭代次数、Hash值的编成方法、Hash值的位数等作为加密密钥。由于该算法的不可逆性,使由密文到明文的逆向攻击失效,但明文和选择性明文攻击仍对该算法有一定的攻击效果。为更加有效地抵御各类明文、选择性明文的攻击,本文对该加密算法的Arnold映射初值、迭代次数等2个关键密钥进行改进,通过增加Arnold映射初值的个数,以及将迭代次数从常量拓展到变量的方法,构造出一个增强的Arnold映射Hash加密算法,从而进一步增加保密强度,提高Arnold映射Hash加密算法对明文、选择性明文攻击的抵抗能力。通过对实验数据的混乱与散布性质分析,改进后的Arnold映射Hash加密算法的平均变化位数和每位平均变化概率更加接近理想状况下的64位和50%的变化概率,算法的保密性能更加良好。
Arnold Mapping Hash encryption algorithm is a kind of encryption method combining two-dimensional chaotic system and hash function. Generally, the initial value of Arnold mapping, the number of iterations, the method of compiling Hash value and the number of bits of Hash value are used as encryption keys. Due to the irreversibility of the algorithm, the reverse attack from ciphertext to plaintext is invalid, but plaintext and selective plaintext attack still have certain attack effect on the algorithm. In order to be more effective against all kinds of plaintexts and selective plaintext attacks, this paper improves on two key keys of Arnold mapping initial value and iteration number of the encryption algorithm. By increasing the number of Arnold mapping initial values, The number of times from the constant to the variable method to construct an enhanced Arnold mapping Hash encryption algorithm to further increase the security strength and improve the Arnold mapping Hash encryption algorithm plaintext, selective plaintext attack resistance. By analyzing the chaotic and scattered nature of the experimental data, the average number of bits and average per-bit change probability of the improved Arnold mapping Hash encryption algorithm is closer to the 64-bit and 50% probability of change under the ideal conditions, and the security of the algorithm is more good.