Method and apparatus for securing and authenticating encoded data and documents containing such data
View Patent ↗A method and apparatus for determining the distance between transitions from a first logical state to a second logical state stored on a medium (i.e., a document). This determination is used to precisely characterize the information pattern in order to authenticate the information and the medium on which the information is stored. The invention uses a reader having a leading and trailing read apparatus which allow information to be read simultaneously from two or more locations spaced a known distance apart. The distance between the centerlines of each read apparatus is preferably an odd integer multiple of one half the distance between logical clock transitions. The distance between a first transition at the leading read apparatus and a next transition at the trailing read apparatus is used as a reference (i.e., the “Reference Value”). The Reference Value is compared with the distance between the first transition and the next transition on the medium (i.e., the “Jitter Value”). Detection of an deviations in spacing between transitions is unaffected by variations in the velocity of the medium with respect to the reader.
1. A chip card with enhanced security for storing information, comprising:
a) a memory device having data encrypted with a signature derived from a series of arbitrary spatial relationships of spatially encoded data;
b) a medium incorporating a spatially encoded memory device, fixed to the exterior of the chip card, for the purpose of storing said spatially encoded data; and
c) a processing element that uses said signature to access the encrypted data in said memory device.
2. A method for encoding a jitter signature into encoded data stored within a magnetic stripe fixed to a chip card wherein pairs of transitions are spaced apart by a non-integer multiple of a reference value, comprising the steps of:
a) generating a jitter signature from a first portion of information stored within a magnetic stripe fixed to a chip card; and
b) encoding said jitter signature in a second portion of the information stored within said magnetic stripe by jitter modulation, whereby said jitter modulation is accomplished by advancing or delaying the encoding timing by a small multiple of the reference value.