Breaking a novel colour image encryption algorithm based on chaos
This work identifies security vulnerabilities in a specific encryption algorithm, which is an incremental contribution to the field of cryptanalysis for image encryption.
The paper analyzes a recently proposed color image encryption algorithm based on chaos and finds that it can be broken with only a few chosen plain-images, specifically requiring ⌈(log₂(3MN))/8⌉ images for the permutation part and 2 images for the substitution part, where MN is the image size.
Recently, a colour image encryption algorithm based on chaos was proposed by cascading two position permutation operations and one substitution operation, which are all determined by some pseudo-random number sequences generated by iterating the Logistic map. This paper evaluates the security level of the encryption algorithm and finds that the position permutation-only part and the substitution part can be separately broken with only $\lceil (\log_2(3MN))/8 \rceil$ and 2 chosen plain-images, respectively, where $MN$ is the size of the plain-image. Concise theoretical analyses are provided to support the chosen-plaintext attack, which are verified by experimental results also.