The invention relates to an efficient 
anonymous authentication method and 
system suitable for an alliance chain and capable of supporting identity 
traceability. According to the method, an 
anonymous authentication technology is utilized to grant a corresponding key to a legal user, so that the user can generate a 
certificate for 
authentication in an interaction process, and identity authenticationis successful if the 
authentication is passed; the 
anonymous authentication technology is constructed based on the 
group signature technology, so that the privacy of the user identity can be protected while the identity 
traceability is supported. The key granted to the user is divided into two components: an anonymous key and a time component. And when the user exits, only the time component which does not exit the 
user needs to be updated, and identity 
revocation of the user can be realized. According to the method, 
authentication can be achieved without depending on a 
third party, privacy of a user can be protected in the authentication process, the identity of the user can be exposed when disputes occur, 
traceability can be achieved, and dynamic joining and exiting of alliance membersand members in an organization can be efficiently achieved after 
system initialization.