Lattice-based multi-identity fully homomorphic encryption method

Abstract

The invention discloses a lattice-based multi-identity fully homomorphic encryption method. The method comprises the following steps: initializing a system; extracting a user key: mapping the first user identity and the second user identity into a reversible matrix by using a full-rank function, and generating a first private key corresponding to the first user identity and a second private key corresponding to the second user identity through vector operation; performing ciphertext generation: obtaining encryption selection of a first user identity, selecting a plaintext message to be encrypted, and performing encrypting to obtain a first ciphertext; decrypting the single identity: decrypting the first user identity through a first private key to obtain a plaintext message; identity conversion: converting the first ciphertext of the first user identity into a second ciphertext corresponding to a second user identity through an identity conversion algorithm; and performing fully homomorphic evaluation: carrying out fully homomorphic operation on the ciphertext after identity conversion and then decrypting the ciphertext. Encryption and decryption of a ciphertext with a single identity are converted into encryption and decryption of a ciphertext with multiple identities, and correct fully homomorphic operation can be realized.

Description

technical field [0001] The invention relates to the technical field of fully homomorphic encryption security, in particular to a lattice-based multi-identity fully homomorphic encryption method. Background technique [0002] Based on the multiplicative homomorphism of the RSA public key encryption system, Rivest et al [Rivest R L, Adleman L, Dertouzos M L. On data banks and privacy homomorphisms [J]. Foundations of Secure Computation, 1978:169-179.] proposed a homomorphism The concept of encryption is to implement operations on plaintext by performing operations on ciphertext without decrypting the ciphertext, and the results are consistent. The proposal of homomorphic encryption has attracted extensive attention from scholars at home and abroad, but the scheme does not fully realize homomorphism, nor can it operate and process ciphertexts any number of times. The identity-based encryption system uses the user's unique identity as the public key, and the private key generat...

AI Technical Summary

Problems solved by technology

Although the above scheme proposes a new identity-based fully homomorphic encryption scheme, in real life, the operation of a single identity cannot meet people's needs for big data and cloud computing.

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