A two-way access authentication method, comprising: obtaining by a first entity a private key g 1 ← ID 1 d (mod N) of the first entity calculated by a third entity based on system parameters after the third entity performs physical identification on an identity of the first entity, and obtaining by a second entity a private key g 2 ← ID 2 d (mod N) of the second entity calculated by the third entity based on the system parameters after the third entity performs physical identification on an identity of the second entity, wherein: the system parameters comprise a product N of two large prime numbers, an integer e satisfying gcd( e, φ) = 1, an integer d satisfying ed ≡ 1(mod φ) and a strong one-way hash function h, with φ () being the Euler's totient function, ( N, e, h) are published system parameters, d is a system's private key kept by the third entity secret, ID1 is the identity that uniquely identifies the first entity, and ID2 is the identity that uniquely identifies the second entity; sending by the first entity an access authentication request message to the second entity according to system parameters predefined by the third entity, and verifying by the second entity a signature signed by the first entity and if the signature is correct, calculating by the second entity a shared master key of the second entity; generating by the second entity an access authentication response message, sending by the second entity the access authentication response message to the first entity, and verifying by the first entity a signature and a message integrity check code of the access authentication response message, and if the signature and the message integrity check code of the access authentication response message are both correct, calculating by the first entity a shared master key of the first entity; and sending by the first entity an access authentication acknowledgement message to the second entity, verifying by the second entity integrity of the access authentication acknowledgement message, and if the verification is passed, the shared master keys of the first and second entities are consistent, thereby accomplishing access authentication. obtaining by a first entity a private key g 1 ← ID 1 d (mod N) of the first entity calculated by a third entity based on system parameters after the third entity performs physical identification on an identity of the first entity, and obtaining by a second entity a private key g 2 ← ID 2 d (mod N) of the second entity calculated by the third entity based on the system parameters after the third entity performs physical identification on an identity of the second entity, wherein: the system parameters comprise a product N of two large prime numbers, an integer e satisfying gcd( e, φ) = 1, an integer d satisfying ed ≡ 1(mod φ) and a strong one-way hash function h, with φ () being the Euler's totient function, ( N, e, h) are published system parameters, d is a system's private key kept by the third entity secret, ID1 is the identity that uniquely identifies the first entity, and ID2 is the identity that uniquely identifies the second entity; sending by the first entity an access authentication request message to the second entity according to system parameters predefined by the third entity, and verifying by the second entity a signature signed by the first entity and if the signature is correct, calculating by the second entity a shared master key of the second entity; generating by the second entity an access authentication response message, sending by the second entity the access authentication response message to the first entity, and verifying by the first entity a signature and a message integrity check code of the access authentication response message, and if the signature and the message integrity check code of the access authentication response message are both correct, calculating by the first entity a shared master key of the first entity; and sending by the first entity an access authentication acknowledgement message to the second entity, verifying by the second entity integrity of the access authentication acknowledgement message, and if the verification is passed, the shared master keys of the first and second entities are consistent, thereby accomplishing access authentication.