A simple public-key attack on phase-truncation-based double-images encryption system

Phase-truncation based double-images cryptosystem can avoid the iterative Fourier transforms and realize double-images encryption. In this paper, a simple public-key attack is proposed to break this cryptosystem by using arbitrary position parameters and three public keys. The attack process is composed of two steps. Firstly, the decryption keys are simply generated with the help of arbitrary position parameters and the three public keys. Secondly, the two approximate values of the original images are obtained by using the generated decryption keys. Moreover, the proposed public-key attack is different from the existing attacks. It is not sensitive to position parameters of the double-images and the computing efficiency is also much better. Computer simulation results further prove its vulnerability.