Cipher

About: Cipher is a research topic. Over the lifetime, 9409 publications have been published within this topic receiving 110309 citations. The topic is also known as: cypher & cryptographic algorithm.

An effective image compression–encryption scheme based on compressive sensing (CS) and game of life (GOL)

Abstract: At present, information entropies of cipher images gotten by some CS-based image cryptosystems are lower than 7, which make them vulnerable to entropy attack. To cope with this problem, we propose a novel image compression–encryption method based on compressive sensing (CS) and game of life (GOL). Encryption architecture of permutation, compression and diffusion is utilized. Firstly, a plaintext-dependent game-of-life-based scrambling method is presented to shuffle the sparse coefficient matrix of plain image, and the permutation matrix is constructed by rules of GOL, which may effectively reduce the adjacent pixel correlation and enhance the scrambling effect. Secondly, the confused matrix is compressed by CS and diffused using a key matrix to get the cipher image. Additionally, a five-dimensional (5D) memristive hyperchaotic system is used to generate chaotic sequences. They are utilized to construct measurement matrix, to generate initial cell matrix of GOL and to produce key matrix. Information entropy of plain image and external key parameters are combined to compute initial values of the hyperchaotic system. Therefore, our algorithm has high sensitivity to original image and it may resist against known-plaintext attack and chosen-plaintext attack. Experimental results and performance analyses demonstrate that the proposed encryption algorithm is effective to withstand various typical attacks, and it may be applied for image secure communication.

Quantum Noise Randomized Ciphers

Abstract: We review the notion of a classical random cipher and its advantages. We sharpen the usual description of random ciphers to a particular mathematical characterization suggested by the salient feature responsible for their increased security. We describe a concrete system known as $\ensuremath{\alpha}\ensuremath{\eta}$ and show that it is equivalent to a random cipher in which the required randomization is affected by coherent-state quantum noise. We describe the currently known security features of $\ensuremath{\alpha}\ensuremath{\eta}$ and similar systems, including lower bounds on the unicity distances against ciphertext-only and known-plaintext attacks. We show how $\ensuremath{\alpha}\ensuremath{\eta}$ used in conjunction with any standard stream cipher such as the Advanced Encryption Standard provides an additional, qualitatively different layer of security from physical encryption against known-plaintext attacks on the key. We refute some claims in the literature that $\ensuremath{\alpha}\ensuremath{\eta}$ is equivalent to a nonrandom stream cipher.

An encryption algorithm inspired from DNA

Abstract: DNA cryptography is a new promising direction in cryptography research that emerged with the progress in DNA computing field. DNA can be used not only to store and transmit information, but also to perform computations. The massive parallelism and extraordinary information density inherent in this molecule are exploited for cryptographic purposes, and several DNA based algorithms are proposed for encryption, authentification and so on. The current main difficulties of DNA cryptography are the absence of theoretical basis, the high tech lab requirements and computation limitations. In this paper, a symmetric key bloc cipher algorithm is proposed. It includes a step that simulates ideas from the processes of transcription (transfer from DNA to mRNA) and translation (from mRNA into amino acids). This algorithm is, we believe, efficient in computation and very secure, since it was designed following recommendations of experts in cryptography and focuses on the application of the fundamental principles of Shannon: Confusion and diffusion. Tests were conducted and the results are very satisfactory.

Scream: A Software-Efficient Stream Cipher

Abstract: We report on the design of Scream, a new software-efficient stream cipher, which was designed to be a "more secure SEAL". Following SEAL, the design of Scream resembles in many ways a block-cipher design. The new cipher is roughly as fast as SEAL, but we believe that it offers a significantly higher security level. In the process of designing this cipher, we re-visit the SEAL design paradigm, exhibiting some tradeoffs and limitations.