Patent ID: 7124441

Claim:
A method of securely providing user information to a user machine adapted to operate in conjunction with an optically readable memory containing information which comprises at least the user information and a gatekeeper program, and having thereon an obscurable section comprising a photoreactive mask layer disposed to alter the detected optical properties of areas of the memory exposed substantially to a wavelength of optical radiation usable to read the memory, the method comprising the steps of: collecting machine-unique information from the user machine; generating a user machine signature based on the machine-unique information; causing the user machine to scan the obscurable section of the memory; determining whether an existing signature is present in the obscurable section; and if no existing signature is present in the obscurable section, causing the generated user machine signature to be written in the obscurable section by selectively irradiating the obscurable section with light of the same wavelength used to read the memory, thereby selectively altering the detected optical properties of the memory in the obscurable section, and providing the user information to the user machine; and if an existing signature is present in the obscurable section, causing the user machine to compare the existing signature to the generated signature, and providing the user information to the user machine if the existing signature matches the generated signature, and denying the user machine access to the user information if the existing signature does not match the generated signature.