一种基于同态公钥加密的遥感影像数字指纹方案

针对非对称指纹计算复杂性高以及带宽效率低的问题，提出了一种基于同态公钥加密的遥感影像非对称指纹方案。在该方案中，内容提供商通过DCT扩频置乱方法加密遥感影像，运用Bresson同态公钥加密来实现解密密钥的非对称分发，通过客户端解密含指纹的遥感影像拷贝，使不同的解密密钥能够生成不同的含指纹拷贝。方案中公钥加密算法并未直接加密遥感影像，由此降低了计算复杂性并提高了加密效率；同时因为内容提供商只需为多个消费者生成相同的指纹拷贝，通过多播传输将其分发给不同的消费者，因此降低了带宽需求。实验表明：在用户数量较大的情况下，该方案可以有效提高带宽效率及加密效率，能够显著降低数据服务器的计算负载，减少用户等待时间。

A Digital Fingerprinting Scheme for Remote Sensing Images based on the Homomorphic Public Key Encryption Algorithm

An asymmetric fingerprinting scheme for remote sensing images based on the homomorphic public key encryption algorithm is proposed for solving the problems of high computational complexity and low bandwidth efficiency in asymmetric digital fingerprinting. In this scheme， the data provider encrypts the remote sensing images via the DCT spread spectrum scrambling method， and the Bresson homomorphic public key encryption algorithm is used to realize asymmetric distribution of the decryption key. The copies of remote sensing images with the fingerprint are decrypted by the client， and different copies with the fingerprint come from different decryption keys. The remote sensing images are not directly encrypted by the public key encryption algorithm， so the complexity of the algorithm is greatly reduced and the encryption efficiency is dramatically improved. Meanwhile， the demand of bandwidth will be reduced and the efficiency of bandwidth will be improved， because data owners not only need to generate one copy with the fingerprint for different users， but also data copies are distributed to different users via multicast transmission. The experiments have shown that the scheme can effectively improve the efficiency of bandwidth and the efficiency of encryption when the number of users is relatively large， which can greatly reduce the computing load of the data server and reduce the waiting time of the users.