A Multi-Level Blocks Scrambling Based Chaotic Image Cipher.
ABSTRACT In this paper, an image encryption scheme based on multi-level blocks scrambling is proposed. The image is first decomposed into non-overlapping blocks and scrambling of these blocks is done by using 2D Cat transform. Multi-level blocks scrambling (MLBS) is implemented by starting with a large block size and the size of blocks gets reduced iteratively at each level. The scrambling of blocks is performed at multiple levels to get cummulative effect. At each level, the control parameters of scrambling are randomly generated through 2D coupled Logistic map to make the process of scrambling key dependent. The scrambled image obtained after carrying out MLBS scrambling is encrypted using chaotic sequence generated by one-dimensional Logistic map. The experimental results show that the proposed encryption scheme can successfully encrypts/decrypts the images with same secret keys. The algorithm has large key space and high sensitivity to a small change in secret keys. The simulation analysis also demonstrates that the ciphered images have high information entropy, very low correlation coefficients and uniform gray level distribution.
- SourceAvailable from: Musheer Ahmad
Conference Paper: Cryptanalysis of Chaos Based Secure Satellite Imagery Cryptosystem.[Show abstract] [Hide abstract]
ABSTRACT: Recently Usama et al. proposed a chaos-based satellite image cryptosystem, which employed multiple one-dimensional chaotic maps in novel manner to enhance the robustness, security and efficiency of sensitive satellite imagery. It is very efficient in terms of encryption time. The authors of the cryptosystem under study claimed that it has high level of security and can be applied to transmit confidential multimedia images over Internet/shared network. Unfortunately, the security analysis of the cryptosystem reveals that it has serious security flaws. Consequently, it is susceptible to a number of attacks. In this paper, the cryptanalysis of original cryptosystem is presented and it is shown that the attacker can recovers the plain-image from given cipher-image under three types of classical cryptographic attacks without knowing the secret key. The simulation results of cryptanalysis demonstrate that the cryptosystem highly lacks security and cannot be utilized for the protection of confidential/sensitive multimedia images such as the satellite imagery.Contemporary Computing - 4th International Conference, IC3 2011, Noida, India, August 8-10, 2011. Proceedings; 01/2011
- [Show abstract] [Hide abstract]
ABSTRACT: Recently, a pixel-chaotic-shuffling (PCS) method has been proposed by Huang et al. for encrypting color images using multiple chaotic systems like the Henon, the Lorenz, the Chua, and the Rossler systems. All of which have great encryption performance. The authors claimed that their pixel-chaotic-shuffle (PCS) encryption method has high confidential security. However, the security analysis of the PCS method against the chosen-plaintext attack (CPA) and known-plaintext attack (KPA) performed by Solak et al. successfully breaks the PCS encryption scheme without knowing the secret key. In this paper we present an improved shuffling pattern for the plaintext image bits to make the cryptosystem proposed by Huang et al. resistant to chosen-plaintext attack and known-plaintext attack. The modifications in the existing PCS encryption method are proposed to improve its security performance against the potential attacks described above. The Number of Pixel Change Rate (NPCR), Unified Average Changed Intensity (UACI), information entropy, and correlation coefficient analysis are performed to evaluate the statistical performance of the modified PCS method. The simulation analysis reveals that the modified PCS method has better statistical features and is more resistant to attacks than Huang et al.'s PCS method.Journal of Information Processing Systems 01/2013; 9(2).