Encryption and decryption method and device based on zipper type dynamic hash and NLFSR

Abstract

An encryption and decryption method based on zipper type dynamic hashes and NLFSRs comprises the following steps that a nonlinear feedback function and a bit transformation Boolean function are used for preprocessing a seed secret key to form a secret key stream sequence; changing the bit value of the plaintext sequence according to the bit transformation Boolean function based on the key stream sequence to form a pseudo plaintext sequence; dividing the pseudo-plaintext sequence into a plurality of paths of pseudo-plaintext subsequences according to the key stream sequence; and calculating a dynamic hash address corresponding to the binary bit of each pseudo plaintext sequence according to a hash mapping rule depending on the key stream sequence, and mapping the pseudo plaintext subsequence hashes which are divided into multiple paths into a ciphertext space to form the ciphertext stream sequence. The method has the beneficial effects that the key stream generator not only uses a nonlinear feedback shift register, but also introduces a bit transformation Boolean function, so that the key stream with longer period and better randomness is obtained; and through a plaintext bit transformation rule and a zipper type dynamic hash mapping rule, the decoding difficulty of the ciphertext stream sequence is improved.

Description

technical field [0001] The present application relates to the field of information security, in particular to an encryption and decryption method and device based on zipper dynamic hash and NLFSR (Nonlinear Feedback Shift Register, nonlinear feedback shift register). This application can generally be used for network communication information encryption, aerospace digital remote control instruction and data encryption, drone digital remote control communication data encryption, early warning aircraft digital communication command system information encryption, GPS satellite digital communication data encryption, mobile communication encryption, and big data encryption , graphic image encryption and e-mail encryption, etc. After encryption, military, political and diplomatic documents can be transmitted using civilian communication networks to save on file transfer costs. Background technique [0002] A stream cipher is generally a symmetric key technique. Because of its si...

AI Technical Summary

Problems solved by technology

Therefore, a defect of this mechanism is that the security strength of the stream cipher depends entirely on the security strength of the keystream sequence. However, there have been many attack techniques on the keystream generator

Another defect of this mechanism is that the encryption and decryption method is single, which leads to the fact that for a short key stream sequence, the ciphertext with good randomness and code distribution uniformity cannot be obtained solely by XOR operation.

Images