多元符号的安全算术编码

摘要

为提高传统算术编码TAC（ traditional arithmetic coding）对密文和选择性明文攻击的抵抗力，提出一种基于多元符号的安全算术编码M⁃SAC（ M⁃ary security arithmetic coding）方案。该方案将数据压缩与加密相结合，利用加密密钥改变信源符号在编码区间中的位置，进而改变TAC的编码区间和编码码字。仿真结果表明：在静态和自适应模型下，当译码器利用错误密钥译码时，该方案比二元随机算术编码BRAC（ binary random arithmetic coding）得到的误符号率SER（ symbol error rate）更高；该方案既不影响压缩效率又能实现对数据的有效加密，对密文和选择性明文攻击有很强的抵抗力。%To improve the TAC resistance to ciphertext and selective plaintext attacks, a novel security arithmetic coding scheme based on M-ary symbol is proposed. It combines data encryption with compression. The modified arithmetic coding methodology changes the encoding interval and codeword of TAC by using an encryption key to alter the symbols orders in the encoding interval. Simulations both on static and adaptive model show that M⁃SAC can obtain higher SER than BRAC when decoding with a wrong key. The proposed encryption algorithm satisfies highly security without loss of compression efficiency, which has strong resistant to ciphertext and selective plaintext attacks.