【摘要】 为提高光学加密系统的安全性与敏感性,设计分阶Fourier变换耦合DNA序列编码的光学图像加密算法。利用SHA-256方法来处理初始明文,形成一个256位密钥,并将其转换为密钥矩阵;引入DNA编码,对明文实施编码操作,得到一个DNA序列矩阵,将其与密钥矩阵完成XOR操作,输出混淆密文;根据256位密钥计算Lorenz系统的初始条件,通过迭代,获取3个随机序列,并将其转换为对应的混沌矩阵,利用不同阶数的Fourier变换,联合3个混沌矩阵,借助光学调制掩码对混淆密文进行级联光学加密。测试结果表明,相对已有光学加密技术,所提方案拥有更高的安全性,呈现出更强的抗明文攻击特性。更多还原

【Abstract】 To improve the security and sensitivity of optical encryption system,an optical image encryption algorithm based on fractional Fourier transform and DNA sequence coding was designed.The SHA-256 method was used to process the initial plaintext for forming a 256 bit key,and it was transformed into a key matrix.The DNA coding was introduced to encode the plaintext for getting a DNA sequence matrix,and the XOR operation was completed using the DNA sequence matrix and the key matrix for outputting the obfuscated cipher.Three initial values of the chaotic Lorenz system were calculated according to the 256 bit key,and three random sequences were obtained by iteration,they were transformed into corresponding chaotic matrix.With the help of Fourier transform of different orders,three chaotic matrices were combined to perform cascaded optical encryption on the confused ciphertext.The test results show that compared with the existing optical encryption technology,the proposed algorithm has higher security and sensitivity,showing stronger ability to resist differential attack and plaintext attack.更多还原