Special ciphertext-only attack to double random phase encryption by plaintext shifting with speckle correlation.

Area of Science:

• Cryptography
• Image Processing
• Information Security

Background:

• Double Random Phase Encoding (DRPE) is a widely used technique for optical image encryption.
• Existing security analyses of DRPE often assume a single ciphertext or lack consideration for plaintext manipulation.
• The vulnerability of DRPE to sophisticated attacks remains an active area of research.

Purpose of the Study:

• To propose a novel ciphertext-only attack (COA) scenario targeting the DRPE technique.
• To demonstrate the effectiveness of this attack by exploiting plaintext shifting.
• To reveal a critical security flaw in DRPE systems under specific manipulation conditions.

Main Methods:

• A specialized ciphertext-only attack (COA) scenario is developed based on plaintext shifting.
• The attacker gains multiple ciphertexts from shifted versions of the same plaintext.
• The proposed attack integrates a speckle correlation method for image recovery.

Main Results:

• The proposed attack successfully recovers the plaintext image by combining ciphertext-only attack principles with speckle correlation.
• The method is effective even when the plaintext image is small and traditional speckle correlation attacks fail.
• Simulation results validate the scheme's ability to crack the DRPE system under the proposed attack scenario.

Conclusions:

• The study identifies a severe security flaw in double random phase encoding (DRPE) systems related to plaintext shifting.
• Minor positional shifts in the plaintext can be exploited to compromise the security of DRPE.
• The findings necessitate a re-evaluation of DRPE security protocols and defenses against such manipulation attacks.