Patent ID: 6609203
Filing Date: 2003-08-19
Classification: G11B

Abstract:
A method of securely providing user information to a user machine adapted to operate in conjunction with an optically readable disc containing information which comprises at least the user information, a digitally written vanishing code, a hidden code, and a gatekeeper program, and having a mask layer deposited vertically adjacent to the vanishing code, wherein the mask layer is optically reactive to the wavelength of optical radiation usable to read the disc by the user machine to obscure the vanishing code after a finite amount of exposure to the wavelength of optical radiation usable to read the disc, such obscuration being a result of a permanent change in the value of the digitally written vanishing code to an invalid code, the method comprising the steps of:causing the user machine to scan the optically readable disc and to install into the user machine memory the gatekeeper program if the gatekeeper program does not exist on the user machine memory, causing the user machine to use the gatekeeper program stored in the user machine memory to locate a region of the optically readable disc containing the vanishing code, causing the user machine to read the vanishing code and store the vanishing code on the user machine memory and granting the user machine access to the user information stored on the optically readable disc, if the vanishing code is readable, causing the user machine to search the user machine memory for a vanishing code that matches the hidden code if the vanishing code is at least partially unreadable, and granting the user machine access to the user information stored on the optically readable disc if such a vanishing code is found, and denying the user machine access to the user information stored on the optically readable disc if such a vanishing code is not found, whereby if the user machine has previously read the vanishing code it will have unlimited access to the user information recorded on the disc, while if the user machine has not previously read the vanishing code it will not have access to user information recorded on the disc.