Known-plaintext attack on encryption domain independent optical asymmetric cryptosystem

In this paper, we show that amplitude- and phase-truncation-based optical asymmetric cryptosystem is vulnerable to known-plaintext attack. The decryption keys are generated with the help of modified Gerchberg-Saxton phase retrieval algorithm from known-plaintext and ciphertext. With the help of the generated keys, the encrypted image, which is encrypted using encryption keys placed in either of the domains (Fourier, Fresnel, or fractional Fourier domain) is decrypted successfully. The vulnerability is proved through the results of computer simulation.