Abstract: An apparatus and method for controlling the feature set of a programmable device by assigning each programmable device a unique serial number, correlating a secret key with each serial number, and keeping that information in a secure location, such as at the manufacturer. Each optional feature set for the programmable devices is assigned a unique code, and software associated with the programmable device operates according to the feature set identified in the feature set code, if an authentication procedure is passed. The authentication procedure utilizes a secure cryptographic algorithm to calculate an authentication code based on the secret key and the authorized feature set for a programmable device. The authentication code is stored in the programmable device. Periodically, the programmable device automatically self checks itself by recalculating the authentication code. If it matches with the authorized authentication code, the authentication procedure is passed.