Encryption method and device with certificate based on identity

The embodiment of the invention provides an encryption method and an encryption device with a certificate based on identity. The method mainly comprises the following steps that an authentication center generates and discloses system parameters; a user generates and discloses a self public key, the identity information and the public key of the user are sent to the authentication center, and the authentication center uses the user identity information and the system parameters for working out the user certificate, and sends the user certificate to the user; the user works out a self private key according to the user certificate and the system parameters. The method and the system provided by the embodiment of the invention have the advantages that the user certificate is worked out through the authentication center by using the identity information and the system parameter of the user, the public key cryptology system and the password system based on the identity are combined, and the key trusteeship problem in the password system based on the identity is solved. According to the embodiment of the invention, the user certificate can be issued, and the transmission of the user certificate through a safe channel is not needed.