基于复合离散混沌动力系统的序列密码算法

利用复合离散混沌系统的特性,提出了两个基于复合离散混沌系统的序列密码算法.算法的加密和解密过程都是同一个复合离散混沌系统的迭代过程,取迭代的初始状态作为密钥,以明文序列作为复合系统的复合序列,它决定了迭代过程中迭代函数的选择(或明文与密钥),然后将迭代轨迹粗粒化后作为密文.由于迭代对初始条件的敏感性和迭代函数选择的随机性,密钥、明文与密文之间形成了复杂而敏感的非线性关系,而且密文和明文的相关度也很小,从而可以有效地防止密文对密钥和明文信息的泄露.复合离散混沌系统均匀的不变分布还使密文具有很好的随机特性.经分析表明,系统具有很高的安全性.

Stream Cipher Algorithms Based on Composite Nonlinear Discrete Chaotic Dynamical Systems

Two approaches are presented to stream cipher utilizing a peculiar dynamical system called as composite discrete chaotic dynamical system (for short, composite system), which consists of two chaotic dynamical systems. The secret keys are the initial state of the chaotic dynamical systems, and the plaintext is used as its composite sequence that decides the choice of iterating function in the iterating process. Because of sensitivity of the composite system to initial conditions and randomness in the iterating process, the approach mingles secret keys with plaintext when using the composite system to produce ciphertext. Therefore they hold very complex and sensitive nonlinear relations. The algorithm is also provided with uniform distributing ciphertext. These peculiarities prevent ciphertext to leak the information of plaintext and secret key and make the security of the algorithms not depend on the complexity of the ciphertext.