Abstract: The initial sensitivity and randomness of the chaotic map make the image encryption algorithm based on chaotic theory become a hot researching field recently. Many people adopt the low-dimension chaotic map to encrypt, however, the high-dimension map is more complex and has more parameters. This paper uses the four-dimension map to encrypt image, at the time of increasing the key quantities, the encryption speed is not reduced. Moreover the abilities of resisting exhaustive attack and statistic attack are enhanced. For an image of 1 024×768 24 bits BMP, encryption cost approximately 0.35 s and decryption cost approximately 0.361 s, then it can meet the transmission requirement.

Key words: chaos, sensitivity, image encryption, confusion, diffusion

摘要： 混沌映射所具有的初值敏感性和随机性，使得基于混沌理论的图像加密算法成为一个研究热点。绝大多数学者都采用低维的混沌映射，而四维混沌映射相比于低维映射参数更多也更复杂。该文用四维混沌映射进行图像加密，在增加密钥量的同时，加密的速度并没有降低，而且具有抗穷举攻击和统计攻击的能力。对一幅1 024×768的24位BMP图像来说，加密时间约为0.35 s，解密时间约为0.361 s，可以满足传输要求。

关键词: 混沌, 敏感性, 图像加密, 混淆, 扩散

CLC Number: 

• TP309