Method, device and mobile terminal for challenge handshake authentication protocol authentication

A method, apparatus and mobile terminal for a Challenge Handshake Authentication Protocol (CHAP) authenticating in a CDMA Evolution to packet Data Optimized (EVDO) network are provided in the present invention. It makes the authentication process of EVDO network be successful, even though an authentication server does not support the Message Digest 5 (MD5) authentication method. The CHAP authentication method includes: receiving a CHAP authentication request which contains a first key value and is sent by an authentication server; when confirming that an identifier supporting MD5 authentication method is stored in the user identify module, calling MD5 authentication method to calculate a first authentication key value with the first key value, and sending the first authentication key value to the authentication server to authenticate; when receiving a CHAP re-authentication request which contains a second key value and is returned by the authentication server according to the first authentication key value after the authentication is failure, calling the Cellular Authentication and Voice Encryption (CAVE) authentication method to calculate a second authentication key value with the second key value, and sending the second authentication key value to the authentication server to authenticate.