Vulnerability of the security enhanced double random phase-amplitude encryption scheme to point spread function attack

The security enhanced double random phase-amplitude encryption (DRPAE) scheme which has been shown to be resistant to the known plaintext attack, is found susceptible to a simple point spread function (PSF) attack, as in case of the DRPE. Analogy of the DRPAE scheme with the 4-f imaging system is utilized to search for the required PSF, and an a priori knowledge of the amplitude mask is not required. Numerical simulations validate the efficacy of our proposed attack. Existence of the linearity in the DRPAE scheme is also examined. (C) 2012 Elsevier Ltd. All rights reserved.