Secure PC Audio download

We need to offer a current customer a secure way to have their customers (who will access their e-commerce site we just built) download a copy of their audio seminar. The audio is currently on CD format, but they want it to be in a audio file format with some sort of security built in that will require the user to type in a key and registration info to make it work. This is an attempt to reduce copyright issues. We know of a few theories to accomplish this, but need a developer with experience in converting CD audio to a secure downloadable version for Windows and MAC. They will consider streaming audio, but the bandwidth costs may be an issue, plus the fee structuring may have to change to subscription, as the audio is very lengthy (4 CD's). Please recommend a methodology for accomplishing this and I will be glad to provide answers to any requirements questions. ## Deliverables 1) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 2) Installation package that will install the software (in ready-to-run condition) on the platform(s) specified in this bid request. 3) Exclusive and complete copyrights to all work purchased. (No GPL, 3rd party components, etc. unless all copyright ramifications are explained AND AGREED TO by the buyer on the site). ## Platform Windows 98/Me/NT4/2K/XP Mac OS 8 and UP