The identical operands commutative encryption and watermarking based on homomorphism

Aiming at the requirement of comprehensive security protection for multimedia information, this paper proposes a new algorithm to realize the combination of encryption and watermarking based on the homomorphism. Under the proposed algorithm scheme, the plaintext watermark embedding operations are mapped to the ciphertext domain by homomorphism to achieve the plaintext watermark embedding in the ciphertext domain; at the same time, the embedded plaintext watermarks are also mapped to the ciphertext domain by homomorphism to achieve the ciphertext watermarking embedding. According to the experimental results, by the proposed algorithm, the order of watermark embedding and data encrypting does not affect the production of the same encrypted-watermarked data, meanwhile, whether the encrypted-watermarked data being decrypted or not does not affect the extraction of embedded watermark. For the operands of encryption and watermarking being the same data, the proposed algorithm has higher security compared with the existing mainstream independent operands based communicative encryption and watermarking.