Lightweight stream cipher LSNRR based on non-linear cyclic shift register

Abstract

Shift registers are cipher components used for generating pseudo random sequences in the field of secret communication, comprising linear feedback shift registers LFSRs, non-linear feedback shift registers NLFSRs, and so on, wherein the maximum period T of the shift register is not greater than 2n. The feedback mode of an n-level non-linear cyclic shift register NRR refers to the following formula, in the formula, i>=0, n>=2, word length m is determined by the number of bits of a platform; <<<j represents ring shift left with j bits; a symbol referring to the description represents modular addition; c is an odd number within the range from 1 to 2<m>-1; initial values a<0>-a<n-1>of n inputted words are unlimited, and each word is an arbitrary m-digit number. When the word length is m bits, the period of the n-level non-linear cyclic shift register NRR is greater than (2<m>)<n>, i.e., the security of the n-level non-linear cyclic shift register NRR is better than the security of a traditional (non-)linear feedback shift register (N)LFSR, and the efficiency of the n-level non-linear cyclic shift register NRR is also better than the efficiency of a common (non-)linear feedback shift register (N)LFSR. The lightweight stream cipher LSNRR is designed through four non-linear cyclic shift registers NRRs, wherein the first NRR is used for secret key schedule, and modular addition is performed for outputs of the other three NRRs to generate a secret key stream of the LSNRR. The efficiency of the LSNRR is better than the efficiency of a common symmetric cipher, thus the LSNRR is suitable for the a resource-constrained environment and a resource-unconstrained environment, and is mainly used for data encryption and decryption.

Description

technical field [0001] The lightweight stream cipher LSNRR based on the nonlinear cyclic shift register NRR is a symmetric cipher in the field of secure communication. It is mainly used for data encryption and decryption in network and information system security, and is suitable for terminals with unlimited resources and limited resources. Terminal interworking. Background technique [0002] Cryptography is divided into symmetric cryptography and asymmetric cryptography. Since the encryption speed of asymmetric ciphers is much lower than that of symmetric ciphers, symmetric ciphers are used as much as possible for data encryption and decryption in network and information system security to improve efficiency. Symmetric ciphers are divided into stream ciphers and block ciphers, both of which have advantages and disadvantages. A common cryptographic component for designing stream ciphers is a shift register, a linear feedback shift register LFSR [1] and nonlinear feedback ...

AI Technical Summary

Problems solved by technology

For the (N)LFSR with the maximum period, its output is absolutely uniform, and it will repeat after traversing all states, and the unpredictability is poor

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