Vulnerability Detection and Improvements of an Image Cryptosystem for Real-Time Visual Protection

Chaos-based cryptosystems are regarded as highly secure techniques for image encryption. However, despite the considerable enhancement of encryption robustness provided by chaotic systems, security vulnerabilities may still arise, potentially leading to drastic damage in contexts involving sensitive data such as medical or military images. Identifying these vulnerabilities and developing corresponding countermeasures are essential to prevent security breaches and achieve higher protection. From this perspective, this research thoroughly examines the security of an image encryption scheme based on the 1D sine-powered chaotic map. This analysis identifies vulnerabilities within the scheme that can reduce it to a permutation-only scheme. Exploiting the found vulnerabilities, three distinct cryptanalysis attacks are proposed in this work. These attacks enable unauthorized individuals to replicate the encryption and decryption processes without possessing the secret key, posing significant security risks. Under ciphertext-only attack, chosen-plaintext attack, and chosen-ciphertext attack conditions, the proposed attacks demonstrate their effectiveness through simulation and experimentation. Notably, the results indicate that these attacks can be executed within seconds and using only a few special plaintext or ciphertext images. An improved version of the analyzed scheme is introduced to address the identified vulnerabilities and enhance its security and speed.