基于混沌理论与DNA动态编码的卫星图像加密算法

针对卫星图像在传输、存储过程中涉及的信息安全问题，该文提出一种新型的基于混沌理论与DNA动态编码的卫星图像加密算法。首先，提出一种改进型无限折叠混沌映射，拓宽了原有无限折叠混沌映射的混沌区间。之后，结合改进型Chebyshev混沌映射与SHA-256哈希算法，生成加密算法的密钥流，提升算法的明文敏感性。然后，利用混沌系统的状态值对Hilbert局部置乱后的像素进行DNA编码，实现DNA动态编码，解决了DNA编码规则较少所带来的容易受到暴力攻击的弱点。最后，使用混沌序列完成进一步混沌加密，从而彻底混淆原始像素信息，增加加密算法的随机性与复杂性，得到密文图像。实验结果表明，该算法具有较好的加密效果和应对各种攻击的能力。

Satellite Image Encryption Algorithm Based on Chaos Theory and DNA Dynamic Coding

Considering the information security problems involved in the transmission and storage of satellite images, a new satellite image encryption algorithm based on chaos theory and DNA dynamic coding is proposed. Firstly, an improved infinite folding chaotic map is proposed, which broadens the chaotic interval of the original infinite folding chaotic map. Then, combined with the improved Chebyshev chaotic map and SHA-256 hash algorithm, the key stream of the encryption algorithm is generated to improve the plaintext sensitivity of the algorithm. Then, the state value of the chaotic system is used to encode the pixels after Hilbert local scrambling to realize DNA dynamic coding, which solves the weakness of being vulnerable to violent attacks caused by fewer DNA coding rules. Finally, the chaotic sequence is used to complete further chaotic encryption, to completely confuse the original pixel information, increase the randomness and complexity of the encryption algorithm, and obtain the ciphertext image. The experimental results show that the algorithm has a better encryption effect and the ability to deal with various attacks.