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.

The Henchman Problem: Measuring Secrecy by the Minimum Distortion in a List

Abstract: We introduce a new measure of information-theoretic secrecy based on rate-distortion theory and study it in the context of the Shannon cipher system. Whereas rate-distortion theory is traditionally concerned with a single reconstruction sequence, in this paper, we suppose that an eavesdropper produces a list of $2^{nR_{\sf L}}$ reconstruction sequences and measure secrecy by the minimum distortion over the entire list. We show that this setting is equivalent to one in which an eavesdropper must reconstruct a single sequence, but also receives side information about the source sequence and public message from a rate-limited henchman (a helper for an adversary). We characterize the optimal tradeoff of secret key rate, list rate, and eavesdropper distortion. The solution hinges on a problem of independent interest: lossy compression of a codeword uniformly drawn from a random codebook. We also characterize the solution to the lossy communication version of the problem in which distortion is allowed at the legitimate receiver. The analysis in both the settings is greatly aided by a recent technique for proving source coding results with the use of a likelihood encoder.

Encrypting units of work based on a trust level

Abstract: A method, apparatus, system, and signal-bearing medium that, in an embodiment, determine a cipher strength based on a trust level associated with a request, create a unit of work based on the request, encrypt the unit of work into a message based on the cipher strength, and send the message to grid servers. In various embodiments, the trust level may be determined based on a security token associated with the request or based on a zone from which the request originates. In various embodiments, the request originates from a client that belongs to the zone or originates from one of the grid servers that belongs to the zone. In an embodiment, a request from a grid server may be associated with a response to a previous unit of work that the grid server executed.

Generation of AES Key Dependent S-Boxes using RC4 Algorithm

Abstract: The increase use of computer and communication system by industry and organizations has increased the risk of theft of proprietary information. Although these threats require a variety of countermeasure, encryption process is a primary method of protecting valuable electronic information. The encryption process also needs to be dynamic in order to face new technique and more advance methods used by cryptanalysis. Substitution box (Sbox) is keystone of modern symmetric cryptosystem .They bring nonlinearity to cryptosystem and strengthen their cryptographic security. In this paper RC4 algorithm which is well known stream cipher is used to generate S-box for advance encryption standard (AES). The generated S-boxes are more dynamic and key dependant which will increase the complexity and also make the differential and linear cryptanalysis (DC&LC) more difficult. Various randomness tests are applied to the customized AES (AES-RC4) algorithm and the results shown that the new design pass all tests which proven its security.

A Novel Approach to Security using Extended Playfair Cipher

Abstract: The well known multiple letter encryption cipher is the Playfair cipher. Here the digrams in the plaintext are treated as single units and converted into corresponding cipher text digrams. However because of the drawbacks inherent in the 5*5 Playfair cipher which adversely affects the security we proposed an 8*8 Playfair cipher. For details one can refer to [1]. This paper analyses the new proposed system. For this we have carried out cryptanalysis and through the avalanche effect we find out that the proposed cipher is a strong one.

High-speed uplink packet access (hsupa) cipher multiplexing engine

Abstract: A combined data packing, cipher and multiplexing engine operable to support high speed uplink packet access (HS-UPA) within user equipment (UE) is provided. This combined cipher multiplexing engine includes a master port, a radio link control (RLC) data packer, and a cipher multiplexing processing module. The master port couples to an advanced microprocessor bus architecture (AMBA) high speed buss (AHB) on which control information for the combined cipher and multiplexing engine is provided. The RLC couples to the master port and receives RLC service data units (SDUs) from the AHB. Then the RLC data packer may concatenate or segment RLC SDUs into RLC packet data units (PDUs) which are stored for use by a cipher multiplexing processing module. The cipher multiplexing processing module retrieves the RLC PDU from the RLC PDU buffer and ciphers to produce ciphered data, if cipher is enabled and multiplexes the ciphered/non-ciphered data together with the RLC header, MAC-es header, MAC-e header and enters the multiplexed results to a hybrid automatic repeat request (HARQ) buffer. A protocol stack executed within the UE activates and provides an array on the formation of the RLC PDU, RLC header information to the combined cipher and multiplexing engine for RLC PDU ciphering and medium access control (MAC) multiplexing of the enhanced data transport channel (E-DCH).