A general quantitative cryptanalysis of permutation-only multimedia ciphers against plaintext attacks

Abstract

In recent years secret permutations have been widely used for protecting different types of multimedia data, including speech files, digital images and videos. Based on a general model of permutation-only multimedia ciphers, this paper performs a quantitative cryptanalysis on the performance of these kind of ciphers against plaintext attacks. When the plaintext is of size M × N and with L different levels of values, the following quantitative cryptanalytic findings have been concluded under the assumption of a uniform distribution of each element in the plaintext: 1) all permutation-only multimedia ciphers are practically insecure against known/chosen-plaintext attacks in the sense that only O (log L (M N )) known/chosen plaintexts are sufficient to recover not less than (in an average sense) half elements of the plaintext; 2) the computational complexity of the known/chosen-plaintext attack is only O(n · (M N ) 2 ), where n is the number of known/chosen plaintexts used. When the plaintext has a non-uniform distribution, the number of required plaintexts and the computational complexity is also discussed. to demonstrate the real performance of the known-plaintext attack for a typical permutation-only image cipher.

Communications and Multimedia Security

“…A quantitative study was reported in [17], where it is shown that for an H × H square image with L grey levels O(log L H 2 ) known plaintexts are sufficient to recover half of the plaintext pixels. The computational complexity of these attacks is O(p · H 4 ), where p is the number of known ciphertexts used, making these attacks practical.…”

Lessons Learnt from the Cryptanalysis of Chaos-Based Ciphers

“…According to the general cryptanalysis on permutation-only ciphers in [69], only log 256 (M N ) chosen plain-images are needed to recover the shuffling matrix P * . In total we need log 256 (M N ) +1 chosen plain-images to perform this chosen-plaintext attack.…”

A Plain Image Dependent Image Encryption Scheme Using Half Pixel Level Interchange Permutation Operation

“…The permutation and diffusion stages will become independent if the plainimage is a homogeneous one with identical pixel gray value. Therefore, such a kind of image encryption schemes can be broken by the following steps: (1) a homogeneous image with identical pixel gray value is applied eliminate the confusion effect; (2) the key streams of the diffusion process is obtained using known-plaintext, chosen-plaintext or chosen-ciphertext attacks; (3) the remaining cipher-image can be regarded as the output of a kind of permutationonly cipher, which has been shown insecure and can be broken by known-plaintext or chosen plaintext attacks [9,10]. As a matter of fact, image encryption schemes with conventional permutation-diffusion architecture have been analyzed or shown to suffer from security drawbacks [11][12][13][14][15].…”