Security authentication method for radio frequency recognition system

The invention discloses a security authentication method for a radio frequency recognition system, which comprises the following steps of: searching an authentication key through an initial ID of an identifier; performing identifier authentication and reader authentication, and after the identifier and the reader pass the authentication, generating a key for data communication; and using the communication key in subsequent communication, and updating the authentication key of the identifier in real time by a security authentication flow during next communication. The method improves the security of the RFID system by updating the authentication key of the identifier in real time and transmitting information in an encrypted mode and other means, fully ensures the forward security of the authentication key, makes attackers incapable of calculating a key adopted by the previous communication from the currently acquired key, is suitable for any RFID communication protocol and can improve the key search efficiency.