Patent ID: 6397331
Filing Date: 2002-05-28
Classification: G06F

Abstract:
A method of expanding secured memory into unprotected memory to define an additional secured memory area, the secured memory being expanded to accommodate storage of an extended code, the extended code being initially stored in the unprotected memory in a location which will become the additional secured memory area, the secured memory and the unprotected memory being portions of an integrated circuit, the integrated circuit having a serial number stored in a memory thereof, which comprises the steps of:retrieving by an authorizing party the serial number stored in the memory of the integrated circuit and retrieving the extended code proposed to be stored in the requested expanded secured memory; verifying by the authorizing party whether the extended code is acceptable to be stored in the expanded secured memory of the integrated circuit; generating a token signal by the authorizing party and communicating the token signal to the integrated circuit, the token signal including at least a digital signature of the extended code, as computed by the authorizing party, receiving the token signal by the integrated circuit; parsing the token signal to separate the digital signature of the authorizing party; verifying by the integrated circuit the digital signature of the authorizing party parsed from the token signal which, if verified, indicates that the authorizing party authorized the expansion of the secured memory by the integrated circuit; and invoking by the integrated circuit a command to expand the secured memory so that the additional secured memory area now encompasses the location of the unprotected memory where the extended code is stored.