Subaudio electronic cipherer and dynamic password generation method thereof

The invention discloses a subaudio electronic cipherer and a dynamic password generation method thereof. The subaudio electronic cipherer comprises a subaudio receiver, a subaudio processor, an electronic cipherer main chip and a display. The subaudio receiver receives a subaudio signal additionally attached to an audio signal. The subaudio processor carries out filtering and shaping processing on the received subaudio signal. The electronic cipherer main chip converts the processed subaudio signal into digital subaudio data and generates a challenge-type dynamic password based on user transaction information in the digital subaudio data. The display displays the generated dynamic password. By using the subaudio electronic cipherer and the dynamic password generation method thereof of the invention, lengthy user transaction information does not need to be input on the electronic cipherer with a limited space and a subaudio signal input mode is used to increase information security.