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

Abstract

An encryption and decryption method and device employing zipper-type dynamic hashing and NLFSR techniques. An encryption process comprises the following steps: using a nonlinear feedback function and a bit-manipulation Boolean function to pre-process a seed key, so as to form a keystream sequence; changing, according to the bit-manipulation Boolean function employing the keystream sequence, a bit value of a plaintext sequence, so as to form a pseudo-plaintext sequence; dividing, according to the keystream sequence, the pseudo-plaintext sequence into multiple pseudo-plaintext subsequences; and calculating, according to a hash mapping rule depending on the keystream sequence, a dynamic hash address corresponding to a binary bit of each respective pseudo-plaintext sequence, and mapping, by means of a hash function, the multiple pseudo-plaintext subsequences to a ciphertext space, so as to form a ciphertext stream sequence. The present application has the following beneficial effects: keystream generators, beside using nonlinear feedback shift registers, also use a bit-manipulation Boolean function so as to obtain keystreams having a longer period and improved randomness; moreover, bit-manipulation rules for plaintexts and mapping rules employing zipper-type dynamic hashing are used to increase the difficulty of decoding ciphertext stream sequences.

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.

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