A system for protecting audio/video content during storage and playback on systems with open buses receives a multiplexed signal, including a plurality of A/V signals and decryption keys. Following a request for a channel, a single scrambled A/V signal and its associated decryption keys are extracted from the multiplexed signal. The decryption keys are PCX-encrypted while the scrambled signal remains untouched. Both the encrypted decryption keys and the scrambled signal are stored on the system. During storage, the surreptitious piracy of the signals may be avoided.