Rapid decryption method for homomorphic encryption scheme

Abstract

The invention relates to the technical field of data security, in particular to a quick decryption method for a homomorphic encryption scheme, which comprises the following steps: an encryption user and a decryption user appoint the used homomorphic encryption scheme in advance, and user sides of the two parties precompute system parameters; the decryption user side receives the encrypted ciphertext; after the decryption user side receives the ciphertext, ciphertext parameters are calculated; performing plaintext recovery on the ciphertext parameter by adopting an improved BSGS algorithm according to the obtained system parameter to obtain a plaintext; if the decryption algorithm of the homomorphic encryption scheme needs to verify the decryption result, ciphertext verification is carried out, namely, if the verification result is correct, the decryption result is output, and if the verification result is wrong, decryption fails; according to the method, the discrete logarithm problem can be rapidly solved when the power exponent is small, and certain universality is achieved; compared with the traditional homomorphic encryption scheme, the fast decryption method provided by the invention can improve the decryption speed of the homomorphic encryption scheme by more than 10 times.

Description

technical field [0001] The invention relates to the technical field of data security, in particular to a fast decryption method for a homomorphic encryption scheme. Background technique [0002] Homomorphic encryption is a cryptographic technique based on computational complexity theory of mathematical problems; that is, to decrypt homomorphically encrypted data, the decrypted result is the same as that obtained by processing the unencrypted original data in the same way. The commonly used decryption method is to use the BSGS algorithm to restore the ciphertext to the plaintext; however, in the process of restoring the plaintext using this algorithm, due to the high cost of calculating the multiplicative inverse, the efficiency of the plaintext restoration process is low, which is not conducive to the restoration of the plaintext. Therefore, there is an urgent need for a method that can quickly decrypt homomorphically encrypted ciphertexts. Contents of the invention [00...

AI Technical Summary

Problems solved by technology

The commonly used decryption method is to use the BSGS algorithm to restore the ciphertext to the plaintext; however, in the process of restoring the plaintext using this algorithm, due to the high cost of calculating the multiplication inverse element, the efficiency of the plaintext restoration process is low, which is not conducive to the restoration of the plaintext

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