A device of the same general physical size and shape as a standard audio cassette tape, but which accepts digital information from any of a variety of sources--including for example: Internet transmission, a digital computer, or memory cards (especially digital memory cards)--and plays this digital information through any, for example, standard audio tape cassette player. The device operates by converting the digital representation of the sound into magnetic signals which are presented to the read/write head of the cassette player equipment. The device allows the user of the cassette player to regulate the audio playback using conventional equipment controls such as: START, STOP, REWIND, FAST REWIND, FORWARD, FAST FORWARD, etc. The device has the same general physical dimensions of a standard audio cassette; at least one digital processor; and a slot into which electronic media such as, for example, memory cards, smart cards having a processor and a memory embodied thereon and other memory media may be inserted. Numerous sensors detect changes in at least one of the tape equipment mechanisms in the audio cassette emulator. Various cryptographic techniques are described for protecting the unauthorized distribution of audio information.