Cryptoanalysis on optical image encryption systems based on the vector decomposition technique in the Fourier domain

Area of Science:

• Optics
• Cryptography
• Information Security

Background:

• Optical cryptosystems are crucial for secure data transmission.
• Vector decomposition techniques, including Equal Modulus Decomposition (EMD) and Random Modulus Decomposition (RMD), are employed in Fourier domain-based optical cryptosystems.
• Enhancements like cascaded EMD structures aim to improve security.

Purpose of the Study:

• To analyze the security of optical cryptosystems utilizing vector decomposition in the Fourier domain.
• To investigate the vulnerabilities of cascaded EMD-based cryptosystems.
• To assess the security of RMD-based cryptosystems and propose attacks.

Main Methods:

• Analysis of cascaded EMD-based cryptosystems to identify security weaknesses.
• Development and application of a chosen-plaintext attack (CPA) and a special attack for cascaded EMD systems.
• Security analysis of RMD-based cryptosystems.
• Proposal of a special attack for RMD systems.

Main Results:

• The cascaded EMD-based cryptosystem, despite an additional EMD structure, does not increase private keys, making it vulnerable to CPA and special attacks.
• The RMD technique improves security by using unequal moduli, but it is still susceptible to attacks where ciphertext reveals plaintext information without private keys.
• This research demonstrates the first successful attacks on both cascaded EMD and RMD-based optical cryptosystems.

Conclusions:

• Existing vector decomposition techniques in optical cryptosystems, including cascaded EMD and RMD, possess exploitable security flaws.
• The proposed attacks highlight critical vulnerabilities that must be addressed for robust optical data security.
• Further research is needed to develop more secure optical cryptosystem designs.