The present invention provides a bi-direction 
authentication method and 
system which belongs to the field of 
network communication. The present invention aims at solving the problems that 
certificate management in present private key authority technology is complex and the 
certificate management can not protect the identity of the users. The present invention provides a bi-direction authority method. The present invention includes the procedures of the 
system initialization and generating 
system parameters, an applicant initializing a dialogue request to establish connection with an 
authorization server, the applicant and the 
authorization server mutually check identity and generate a pair of main key which is used for the four-procedure-hand-shaking. The present invention also provides a bi-direction 
authorization system. The system includes a parameter initialization module, an establishing dialogue connecting module, a 
server identity 
verification module and an applicant identify 
verification. Applications of the technical proposal of the present invention can reduce the establishing and maintenance cost of the system, to enhance the running efficiency of the system, and to realize the target of protecting applicants.