Method and System for Group-oriented Encryption and Decryption with Selection and Exclusion Functions

A method for performing group-oriented encryption and decryption with selection and exclusion functions, comprising:

• acquiring an encryption mode of a to-be-transmitted message and setting an aggregation function corresponding to the encryption mode during encryption according to a preset mapping relationship between the encryption mode and the aggregation function;
• acquiring any selected subset S and public parameters, and outputting an aggregated value of the subset S according to the acquired aggregation function, the subset S and the public parameters;
• and
• generating a ciphertext of the to-be-transmitted message according to the public parameters, the to-be-transmitted message and the aggregated value.

A system for performing group-oriented encryption and decryption with selection and exclusion functions, comprising:

• an encryption selection unit, which is configured to acquire an encryption mode of a to-be-transmitted message, and set an aggregation function corresponding to the encryption mode during encryption according to a preset mapping relationship between the encryption mode and the aggregation function;
• an encryption aggregation unit, which is configured to acquire any selected subset S and public parameters, and output an aggregated value of the subset S by using the acquired aggregation function corresponding to the encryption mode during encryption, the subset S and the public parameters;
• a ciphertext generating unit, which is configured to generate a ciphertext of the to-be-transmitted message according to the public parameters, the to-be-transmitted message and the aggregated value of the subset S;
• a set operation unit, which is configured to receive the ciphertext, acquire the encryption mode and the subset S comprised in the received ciphertext, and operate the subset S and an identity of a current decryptor according to the encryption mode to output a new subset S′;
• a decryption selection unit, which is configured to acquire an aggregation function corresponding to the encryption mode during decryption according to the preset mapping relationship between the encryption mode and the aggregation function;
• a decryption aggregation unit, which is configured to acquire the public parameters, and output an aggregated value of the new subset S′ by using the acquired aggregation function corresponding to the encryption mode during decryption, the new subset S′ and the public parameters;
• and
• a plaintext generating unit, which is configured to acquire a private decryption key of the current decryptor, decrypt the received ciphertext according to the public parameters, the aggregated value of the new subset S′ and the private decryption key, so as to obtain the to-be-transmitted message.