Secure Image Watermarking in Cloud Computing with Distributed Paillier Cryptosystem

As individuals and companies become more aware of copyright, image watermarking technology is being used more and more in reality. Due to the limitation of local storage and computing power and privacy protection concerns, privacy-preserving watermarking techniques based on cloud computing are gradually gaining more and more attention. We propose an encrypted image watermarking scheme based on discrete cosine transform (DCT) under cloud computing. Using homomorphic encryption (HE), we achieve secure embedding of watermarks on images in the homomorphic encryption domain. The cloud server accomplishes the watermark embedding algorithm. During the embedding process, the cloud server does not need to decrypt the encrypted image, thus ensuring the security of the original image data. We theoretically analyze the security and computational complexity of the whole scheme. Our experimental results show the effectiveness and reliability of our watermarking scheme.