1. A method for using a device to render content to provide at least one of an audible and visual signal for perception by a person, comprising: receiving in said device a signal stream comprising content in which the content in said signal stream is scrambled; receiving in said device a first key; applying, in said device a key based descrambling algorithm which takes as inputs at least one key and a signal stream and produces as output a descrambling algorithm output signal, to said first key and said signal stream, to produce a signal stream descrambling algorithm output signal; and generating, in said device, at least one of an audible and a visual signal, based upon said signal stream descrambling algorithm output signal.