Security payment authentication device adopting audio interface to communicate

The utility model provides a security payment authentication device adopting an audio interface to communicate. The device is used for butt joint with an audio interface of a terminal, and comprises a digital certificate security module, an audio encoding and decoding module, and a battery, wherein the digital certificate security module is used for storing a digital certificate and completing authentication algorithm, the audio encoding and decoding module is in signal connection with the digital certificate security module and is used for converting data from the digital certificate security module into analog signals and transmitting to the terminal and converting analog signals from a left channel or a right channel of the terminal into digital signals and inputting to the digital certificate security module, and the battery supplies power for the digital certificate security module and the audio encoding and decoding module. The security payment authentication device adopting the audio interface to communicate can be used both in a mobile terminal or a non-mobile terminal which has an audio interface, is relatively wide in application range, relatively convenient to use, and relatively good in integration degree, and satisfies the development trends of digital products and products in the communication field currently.