Patent ID: 7076432

Claim:
In a portable audio data processing apparatus comprising a micro-controller coupled to a digital signal processor, the apparatus having a key file and a decryption program stored therein, the apparatus adapted to be removably coupled to a data storage device having a unique identifier, an audio data file and a decoder file stored therein, a method for processing the audio data file, the method comprising the steps of: identifying first and second keys stored in a memory of the micro-controller in response to the decryption program; retrieving the audio data file and the decoder file from the data storage device in response to a user selection of the audio data file; decrypting the decoder file using the first key and the decryption program; generating a third key using to the second key and the unique identifier; decrypting the audio data file using the third key and the decryption program; decoding the decrypted audio data file using the decrypted decoder file; and providing the decrypted, decoded audio data file to an output device.