Patent ID: 8732464

Claim:
A bidirectional entity authentication method with introduction of an online third party, comprising the steps of: 1) transmitting, by an entity B, to an entity A a message 1 comprising a random number R B , an identity I B and an optional text Textl; 2) transmitting, by the entity A, to a trusted third party TP a message 2 comprising a random number R′ A , the random number R B , an identity I A , the identity I B and an optional text Text 2 upon reception of the message 1 ; 3) examining, by the trusted third party TP, the entities A and B for legality against the identities I A and I B upon reception of the message 2 ; 4) returning, by the trusted third party TP, to the entity A a message 3 comprising entity verification results Res A and Res B , a token TokenTA and an optional text Text 5 or comprising the entity verification results Res A and Res B , tokens TokenTA 1 and TokenTA 2 , and the optional text Text 5 after examining the entities A and B for legality; 5) transmitting, by the entity A, to the entity B a message 4 comprising a token TokenAB and the identity I A upon reception of the message 3 ; 6) verifying, by the entity B, upon reception of the message 4 ; 7) transmitting, by the entity B, a message 5 comprising a token TokenBA to the entity A; and 8) verifying, by the entity A, upon reception of the message 5 , wherein the step 6) comprises: 6.1) verifying a signature of the trusted third party TP in TokenTA or TokenTA 2 and examining the random number R B generated by the entity B in the message 1 and the random number R B in the signature of the trusted third party TP comprised in TokenTA or TokenTA 2 for consistency, and performing a step 6.2) if the verification is passed; 6.2) obtaining the verification result Res A of the entity A and performing a step 6.3) if the entity A is legally valid; otherwise, ending or performing the step 7); and 6.3) obtaining a public key of the entity A, verifying a signature of the entity A in TokenAB, examining an identifier of the entity B and an entity identifier (B) in the signature of the entity A comprised in TokenAB for consistency, checking the random number R B generated by the entity B in the message 1 and the random number R B in the signature of the entity A comprised in TokenAB for consistency, and finishing, by the entity B, authentication of the entity A and performing the step 7) if the verification is passed.