Abstract: A digital content file distribution, transmission, and protection system comprises a digital content provider having stored therein a digital content file such as an audio file, video file, literature, program file, etc. The digital content provider includes an authentication interface and a USB port from which the digital content file may be downloaded. The system also contemplates a portable device to which the digital content file will be transferred. This portable device includes an authentication interface and a USB port, and conforms to the USB storage device class. The portable device communicates with the digital content provider via the USB interface and, pending the establishment of a trusted relationship, downloads the digital content file therefrom. The establishment of the trusted relationship with the portable device is accomplished through communications between the authentication interfaces over the USB.