215 citations · 1k across the 21 of their papers we have counts for
14 papers · 1 filter
Recovering the Block-wise Relationship in an Encryption-Then-Compression System
Chengqing Li, Sheng Liu
Joint encryption and compression is an ideal solution for protecting security and privacy of image data in a real scenario, e.g. storing them on an existing cloud-based service lik…
On the security defects of an image encryption scheme
Chengqing Li, Shujun Li, Muhammad Asim +3
This paper studies the security of a recently-proposed chaos-based image encryption scheme, and points out the following problems: 1) there exist a number of invalid keys and weak…
Breaking a chaotic image encryption algorithm based on perceptron model
Yu Zhang, Chengqing Li, Qin Li +2
Recently, a chaotic image encryption algorithm based on perceptron model was proposed. The present paper analyzes security of the algorithm and finds that the equivalent secret key…
Breaking an image encryption algorithm based on chaos
Chengqing Li, Michael Z. Q. Chen, Kwok-Tung Lo
Recently, a chaos-based image encryption algorithm called MCKBA (Modified Chaotic-Key Based Algorithm) was proposed. This paper analyzes the security of MCKBA and finds that it can…
Breaking a modified substitution-diffusion image cipher based on chaotic standard and logistic maps
Chengqing Li, Shujun Li, Kwok-Tung Lo
Recently, an image encryption scheme based on chaotic standard and logistic maps was proposed by Patidar et al. It was later reported by Rhouma et al. that an equivalent secret key…
Optimal quantitative cryptanalysis of permutation-only multimedia ciphers against plaintext attacks
Chengqing Li, Kwok-Tung Lo
Recently, an image scrambling encryption algorithm of pixel bit based on chaos map was proposed. Considering the algorithm as a typical binary image scrambling/permutation algorith…
A Differential Cryptanalysis of Yen-Chen-Wu Multimedia Cryptography System (MCS)
Chengqing Li, Shujun Li, Kowk-Tung Lo +1
At ISCAS'2005, Yen et al. presented a new chaos-based cryptosystem for multimedia transmission named "Multimedia Cryptography System" (MCS). No cryptanalytic results have been repo…
Breaking a Chaotic Cryptographic Scheme Based on Composition Maps
Chengqing Li, David Arroyo, Kwok-Tung Lo
Recently, a chaotic cryptographic scheme based on composition maps was proposed. This paper studies the security of the scheme and reports the following findings: 1) the scheme can…
Breaking a new substitution-diffusion based image cipher using chaotic standard and logistic maps
Chengqing Li, Shujun Li, Kwok-Tung Lo
Recently, an image encryption scheme based on chaotic standard and logistic maps was proposed. This paper studies the security of the scheme and shows that it can be broken with on…
Cryptanalysis of an Image Encryption Scheme Based on a Compound Chaotic Sequence
Chengqing Li, Shujun Li, Guanrong Chen +1
Recently, an image encryption scheme based on a compound chaotic sequence was proposed. In this paper, the security of the scheme is studied and the following problems are found: (…
Cryptanalysis of an image encryption scheme based on the Hill cipher
Chengqing Li, Dan Zhang, Guanrong Chen
This paper studies the security of an image encryption scheme based on the Hill cipher and reports its following problems: 1) there is a simple necessary and sufficient condition t…
Cryptanalysis of an Encryption Scheme Based on Blind Source Separation
Shujun Li, Chengqing Li, Kwok-Tung Lo +1
Recently Lin et al. proposed a method of using the underdetermined BSS (blind source separation) problem to realize image and speech encryption. In this paper, we give a cryptanaly…
On the security of the Yen-Guo's domino signal encryption algorithm (DSEA)
Chengqing Li, Shujun Li, Der-Chyuan Lou +1
Recently, a new domino signal encryption algorithm (DSEA) was proposed for digital signal transmission, especially for digital images and videos. This paper analyzes the security o…
Chosen-Plaintext Cryptanalysis of a Clipped-Neural-Network-Based Chaotic Cipher
Chengqing Li, Shujun Li, Dan Zhang +1
In ISNN'04, a novel symmetric cipher was proposed, by combining a chaotic signal and a clipped neural network (CNN) for encryption. The present paper analyzes the security of this…