Digital right management method, apparatus, and system

A first user equipment, comprising:

• a common public key determining module configured to generate a common public key based on one or more public keys of one or more second user equipments intended to share digital contents, respectively;
• a ciphertext generating module coupled to the common public key determining module and configured to encrypt a key of the digital contents with the common public key, to generate a ciphertext of the key of the digital contents;
• an authorization certificate determining module coupled to the ciphertext generating module and configured to generate from the ciphertext a new authorization certificate corresponding to the digital contents;
• and
• an authorization certificate transmitting module coupled to the authorization certificate determining module and configured to transmit the new authorization certificate and the digital contents to the second user equipments to instruct the second user equipments to share the digital contents in accordance with the new authorization certificate.

A digital right management method, comprising:

• generating, by a server, a common public key from one or more public keys of one or more second user equipments intended to share digital contents, respectively;
• encrypting, by the server, a key of the digital contents with the common public key to generate a ciphertext of the key of the digital contents;
• generating, by the server, from the ciphertext a new authorization certificate corresponding to the digital contents;
• and
• transmitting, by the server, the new authorization certificate to the second user equipments through a first user equipment which has access right to the digital contents to instruct the second user equipments to share the digital contents in accordance with the new authorization certificate.

A digital right management server, comprising:

• a common public key generating module configured to generate a common public key from one or more public keys of one or more second user equipments intended to share digital contents, respectively;
• an encrypting module coupled to the common public key generating module and configured to encrypt a key of the digital contents with the common public key to generate a ciphertext of the key of the digital contents;
• an authorization certificate generating module coupled to the encrypting module and configured to generate from the ciphertext a new authorization certificate corresponding to the digital contents;
• and
• a transmitting module coupled to the authorization certificate generating module and configured to transmit the new authorization certificate to the second user equipments through a first user equipment having access right to the digital contents, to instruct the second user equipments to share the digital contents in accordance with the new authorization certificate.