The terminal comprises a tuner, a security chip and a digital television terminal main chip. The tuner is used to receive cable television broadcast data through a cable for cable televisions, and transmit the received cable television broadcast data to the security chip. A key message required by CA is stored in the security chip. The security chip is used to extract stream media of a program needing to be played from the received cable television broadcast data, descramble the stream media according to the stored key message required by the CA, encrypt the descrambled stream media, and transmit the encrypted stream media to the digital television terminal main chip. The digital television terminal main chip is used to decrypt the received encrypted stream media, decode the decrypted stream media to obtain audio and video data, and output the audio and video data.