The Design Of The Two Revocable Certificateless Encryption Scheme

With the rapid development of the networks,people can share or circulate various information anytime and anywhere,which brings great convenience to people’s lives and learning.However,as the amount of information being transmitted increases,some cases of malicious data theft are being to emerge.If sensitive data is leaked,it will cause huge losses,such as personally identifiable information,internal information of the company,etc.Revocable encryption,as a cryptographic system to protect the secure transmission of information,can not only achieve the privacy of system data,but also revoke some users who leave or key leakage in time to avoid losses.As one of the public key cryptographic systems,certificateless encryption has no certificate management and key custody problems compared to traditional public key cryptography.Therefore,in this paper,we focus on revocable certificateless encryption and do the following work:1.We construct a revocable certificateless encryption scheme for the multi-user scenario and prove the security of the scheme under the DDH and DBDH.This scheme realizes the revocation of illegal user rights in multi-user scenarios,and the same information only needs to be encrypted only once to be sent to multiple users,effectively improving the efficiency of system operation.By being better suited to the mobile user scenario than other revocable encryption schemes.2.A certificateless revocable encryption scheme with ciphertext updates is constructed.Compared with the proposed revocable encryption scheme with ciphertext update,the key generation center no longer needs to send the time update key to the cloud for updating the ciphertext,and the cloud can update the ciphertext with a secret value that it sets,reducing the threat caused by the transmission of the time key.In addition,it has less overhead than the proposed scheme in the time-update key generation phase,which improves efficiency and security.