集成随机置乱和环论的图形图像公钥加密技术

Public Key Cryptosystem for Graphics and Image Based on Integrating Random Scrambling Permutation and Ring Theory

图形图像中信息量庞大、存在数据冗余,为了发挥公钥加密的优势,实施高效率的公钥加密解密,提出基于三维随机矩阵变换和Gray置乱变换的2类置乱变换技术.对于N阶图形图像密钥空间至少为N6;结合改良的NTRU公钥密码技术,建立了一种新型的图形图像公钥密码体制.该密码体制加密解密变换的时间复杂度低,能达到抵御选择明文等攻击的安全性.在此基础上,开发了一套数字多媒体随机置乱公钥加密系统.数值仿真实验表明:该系统可以对bmp,png,pcx等格式的数字图形图像,wav,au等格式的数字音频,dat,txt等格式的数字文本进行快速安全的公钥加密,且密文可保持原来的多媒体格式.

Graphics and image are often of huge amount of data and with much redundancy. For taking into account of these characteristics and for the efficient implementation of the digital image eneryption/deeryption and making use of the advantages of public key features, a three-dimension random matrix scrambling permutation and a Gray scrambling permutation are proposed, which creates a large cipher key space of at least N^6 keys for N-ordered image. Combining with the improved version of NTRU, a new public cryptosystem for digital graphics and image is proposed. Analysis shows that this eryptosystem is of low time complexity and can protest against chosen plaintext attacks. The experiments with our implementation of the cryptosystem for digital multimedia show that many multimedia format such as digital image of BMP, PNG, or PCX format, digital audio of wav or au format, and TXT or DAT format text can be quickly encrypted using public keys and decrypted using private keys.