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 Efficient Chaotic Image Cryptosystem Based on Simultaneous Permutation and Diffusion Operations

Abstract: Recently, several multimedia encryption techniques with permutation–diffusion architecture have been developed. The traditional architecture applies the diffusion and permutation functions as two separate phases. This separable design enables the attacker to launch several forms of attacks in addition to the degradation of the encryption speed. Furthermore, during the diffusion phase, the image pixels are masked in a static order, which may expose significant information about the encryption technique to the attacker. Accordingly, to remedy these problems, this paper suggests an efficient image cryptosystem based on simultaneous permutation and diffusion functions that process the image pixels in a dynamic order fashion. Specifically, the proposed method employs the Chebyshev-Chebyshev map to horizontally and vertically mix the plain-image information. Then, it utilizes the modified Logistic map to mask the image pixels and shuffle the masked values simultaneously. Meanwhile, the control parameters of the employed chaos systems are directly correlated to the plain-image to assure that different key-streams are created for distinct plain-images. Simulation results and security scrutiny confirm that the suggested cipher has several brilliant characteristics, including the robustness against various types of attacks.

Totally secure classical networks with multipoint telecloning (teleportation) of classical bits through loops with johnson-like noise

Abstract: First, we show a new inexpensive defense against intruders and the man-in-the-middle attack in the Kirchhoff's-loop-Johnson-like-noise (KLJN) cipher. Then instead of point-to-point communication, we propose a high efficiency, secure network. The (in the idealistic case totally secure) classical network is based on an improved version of the KLJN cipher. The network consists of two parallel networks: i) a chain-like network of securely communicating, electrically isolated Kirchhoff-loops with Johnson-like noise and driven by a specific switching process of the resistances; ii) and a regular non-secure data network with a Coordinator-server. If the classical network is fast enough, the chain-like network of N communicators can generate and share an N bit long secret key within a single clock period of the ciphers and that implies a significant speed-up compared to the point-to-point key exchanges used by quantum communication or RSA-like key exchange methods. This is a teleportation-type multiple telecloning of the classical information bit because the information transfer can take place without the actual presence of the information bit at the intermediate points of the network. At the point of the telecloning, the clone is created by the product of a bit coming from the regular network and a secure bit from the local KLJN ciphers. The same idea could be implemented with quantum communicator pairs producing entangled secure bit at the two ends. This is the telecloning of classical bits via quantum communicator networks without telecloning the quantum states.

An Improved Image Encryption Algorithm based on Chaotic System

Abstract: The security of stream cipher, which is known as one of the main cipher techniques, is dependents completely on the quality of generated pseudo-stochastic sequences. Chaotic systems can produce the pseudo-random sequences with good randomness, therefore, these systems are suitable to the stream cipher. In this paper, a new encryption algorithm is proposed by analyzing the principle of the chaos encryption algorithm based on logistic map. Moreover, the security and performance of the proposed algorithm is also estimated. The experimental results based on coupled chaotic maps approve the effectiveness of the proposed method, and the coupled chaotic maps shows advantages of large key space and high-level security. The ciphertext generated by this method is the same size as the plaintext and is suitable for practical use in the secure transmission of confidential information over the Internet.

DES cipher processor for full duplex interleaving encryption/decryption service

Abstract: A full duplex DES cipher processor (DCP) supports to execute sixteen rounds of data encryption standard (DES) operation in four encryption modes and four decryption modes, namely: Electronic Code Book (ECB) mode, Cipher Block Chaining (CBC) mode, Cipher Feedback (CFB) mode, and Output Feedback (OFB) mode for both encryption and decryption. A DCP is composed of an I/O unit, an IV/key storage unit, a control unit, and an algorithm unit. The algorithm unit is used to encrypt/decrypt the incoming text message. The algorithm unit having a crypto engine allows encryption and decryption performed alternately, by sharing the same crypto engine. Since for crypto applications in communication services like T1, E1, V.35, the algorithm unit operation time is much shorter than the data I/O time; in other word, the algorithm unit is in the idle state mostly. The full duplex operation is achieved by storing the interim results of the DES encryption operation in a cipher text buffer (CTB) and the decryption results in a plain text buffer (PTB), where the CTB and PTB are in the crypto engine. The full duplex DCP has two ports, one for encrypting and the other for decrypting. In addition, the DCP can also be used for single port simplex or dual port simplex applications.

Parallel AES Encryption Engines for Many-Core Processor Arrays

Abstract: By exploring different granularities of data-level and task-level parallelism, we map 16 implementations of an Advanced Encryption Standard (AES) cipher with both online and offline key expansion on a fine-grained many-core system. The smallest design utilizes only six cores for offline key expansion and eight cores for online key expansion, while the largest requires 107 and 137 cores, respectively. In comparison with published AES cipher implementations on general purpose processors, our design has 3.5-15.6 times higher throughput per unit of chip area and 8.2-18.1 times higher energy efficiency. Moreover, the design shows 2.0 times higher throughput than the TI DSP C6201, and 3.3 times higher throughput per unit of chip area and 2.9 times higher energy efficiency than the GeForce 8800 GTX.