中文摘要：

为提高混沌通信系统的安全性能，在分段抛物映射基础上提出一种利用复合序列的混沌加密方案。该算法通过随机改变区间划分，克服了现有混沌映射的局限性，提高了混沌序列的复杂度．对图像信息加密的理论分析和仿真结果表明，该方案有较高的保密性能，可抵御多种类型的攻击，并扩大了密钥空间．

英文摘要：

To improve the security features of chaotic communication system , a chaotic encryption scheme was developed based on piecewise parabolic map, and composite sequence was used. The scheme overcomes the limitation of current chaotic map through stochasticly changing the interval division, and the complexity of chaotic sequence was improved. Simulations on image encryption show that the scheme has excellent security features to fight back some kinds of attacks, and enlarges the key space.