Ciphertext-only attack on a joint transform correlator encryption system

Abstract

A ciphertext-only attack (COA) on a joint transform correlator (JTC) encryption system is proposed. From the perspective view of optical cryptanalysis, we find out that the issue to be solved in the COA scheme could be transferred into a phase retrieval problem with single intensity measurement. And in this paper, the hybrid input-output (HIO) algorithm is employed to handle this issue with the help of an inartificial signal domain support and a given frequency domain constraint. Meanwhile, we provide a set of numerical simulations to demonstrate the validity and feasibility of the presented method.

Nonlinear image encryption using a fully phase nonzero-order joint transform correlator in the Gyrator domain

“…For all these reasons, we can say that the proposed nonlinear fully phase nonzeroorder JTC-based encryption system in the GD is resistant to the CPA, KPA and COA described in [23], [24] and [25], respectively.…”

“…The chosen-plaintext attack (CPA) [23], the known-plaintext attack (KPA) [24] and the ciphertext-only attack (COA) [25] have proven that the JTC-based encryption systems proposed in the references [9,11,12] are vulnerable to several attacks. The encryption systems of references [9,11,12] were described in the Fourier domain with a RPM as a key.…”

“…The COA implemented in [25] uses an iterative phase retrieval algorithm for retrieving an arbitrary plaintext by using only a ciphertext, whenever the plaintext was encoded in amplitude at the input plane of the JTC-based encryption scheme. The COA described in [25] fails when is applied to the encryption scheme proposed in this paper, because the plaintext is encoded in phase at the input plane of the JTC architecture.…”

“…The COA described in [25] fails when is applied to the encryption scheme proposed in this paper, because the plaintext is encoded in phase at the input plane of the JTC architecture. The difficulty to obtain any success by attacking our encryption system has been significantly increased due to the hardness of retrieving the phase information (the plaintext encoded in phase) from a single intensity (ciphertext) for the phase retrieval algorithm [22,25,40]. The COA is not able to retrieve the correct values of the RPMs r(x, y) and h(x, y) either [25].…”

“…This weakness is due to the linear property of the DRPE method [21]. The DRPE implemented with a JTC is also vulnerable to CPA [23], KPA [24], and COA [25]. These plaintext attacks can be extended to the DRPE systems in the GD, provided the rotation angle of the Gyrator transform (GT) [26] is already known.…”