Multi-images encryption and watermarking with small number of keys via computational ghost imaging

A computational ghost imaging encryption and watermarking method with a small key storage space is proposed. This method uses the Arnold transform to rearrange the measurement matrix in the computational ghost imaging (CGI), using the parameters in the transform as encryption/decryption keys. To reduce the risk of key leakage, the independent component analysis (ICA) method is introduced to analyze the CGI signals, making them statistically independent from each other and further increasing the difficulty of cracking. Two watermarking strategies are proposed that can identify illegal data tampering by verifying the integrity of the watermark. The feasibility of this method is verified by both numerical simulations and optical experiments. The research results represent an optical imaging encryption and watermarking technique with multi-images and multi-user characteristics. As its key storage requirements are small, it can be applied to confidential channels with low speeds, such as quantum cryptography.