说明：  ：针对正交频分复用－无源光网络（ＯＦＤＭ－ＰＯＮ）传输系统中的数据安全与高峰均功率比（ＰＡＰＲ） 问题，提出一种基于混沌映射的ＰＡＰＲ降低与数据加密算法。该加密算法，首先利用拉格朗 日多项式隐藏混沌映射初值实现密钥保护；然后，利用混沌映射生成二值序列，通过正向异或与 反向异或对明文进行加密得到动态密文，以抵抗选择明文攻击；最后，采用混沌加密的恒包络零 自相关（ＣＡＺＡＣ）矩阵与ＯＦＤＭ 符号相乘降低ＰＡＰＲ。实验结果表明，该加密算法可实现密钥的 隐藏，且生成的动态密文能够有效抵抗选择明文攻击。同时，相较于普通的ＯＦＤＭ－ＰＯＮ系统，该 算法能够实现～２．４ｄＢ（ＰＡＰＲ＝１０－３）的ＰＡＰＲ降低与～１ｄＢ（ＢＥＲ＝１０－３）的接收灵敏度提升，进 一步提升了传输性能。
(Data Security and Peak-to-Average Power Ratio (PAPR) in Orthogonal Frequency Division Multiplexing Passive Optical Network (OFDM-PON) Transmission System To solve this problem, a chaotic map based PAPR reduction and data encryption algorithm is proposed. First, Lagrange is used in the encryption algorithm. The Japanese polynomial hides the initial value of chaotic mapping to realize key protection; then, the chaotic mapping is used to generate binary sequence, and the forward XOR and AND are used to protect the key. Reverse XOR encrypts plaintext to get dynamic ciphertext to resist the selective plaintext attack. Finally, the constant envelope zero of chaotic encryption is adopted.)