System and method for communication between smart cards
First Claim
1. A method for determining an approximate current time using a first portable device and a second portable device, the first portable device having a first storage device, the second portable device having a second storage device, the first storage device storing thereon a first sequence number, the second storage device storing thereon a second sequence number, wherein the first and second sequence numbers comprise information on a first and a second trusted time embedded in the respective storage devices, the method comprising the steps of:
- comparing the first sequence number to the second sequence number, the first sequence number being indicative of a the first trusted time provided on the first portable device, the second sequence number being indicative of a the second trusted time provided on the second portable device; and
if the first trusted time is older than the second trusted time, setting the first sequence number to have a value of the second sequence number and conversely,if the second trusted time is older than the first trusted time, setting the second sequence number to have a value of the first sequence number so that the older trusted time information embedded on one of two portable devices is mutually replaced with the newer trusted time information embedded on the other portable device.
1 Assignment
0 Petitions
Accused Products
Abstract
A method and system which provides communication between a first portable device and a second portable device. The first portable device stores a first sequence number and a first key, and the second portable device stores a second sequence number and a second key. Verification is performed using the first and second keys. The first sequence number is compared to the second sequence number. If the second sequence number is newer than the first sequence number, the first sequence number is set to have a value of the second sequence number if the verification succeeds. If the first sequence number is newer than the second sequence number, the second sequence number is set to have a value of the first sequence number if verification succeeds.
18 Citations
18 Claims
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1. A method for determining an approximate current time using a first portable device and a second portable device, the first portable device having a first storage device, the second portable device having a second storage device, the first storage device storing thereon a first sequence number, the second storage device storing thereon a second sequence number, wherein the first and second sequence numbers comprise information on a first and a second trusted time embedded in the respective storage devices, the method comprising the steps of:
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comparing the first sequence number to the second sequence number, the first sequence number being indicative of a the first trusted time provided on the first portable device, the second sequence number being indicative of a the second trusted time provided on the second portable device; and if the first trusted time is older than the second trusted time, setting the first sequence number to have a value of the second sequence number and conversely, if the second trusted time is older than the first trusted time, setting the second sequence number to have a value of the first sequence number so that the older trusted time information embedded on one of two portable devices is mutually replaced with the newer trusted time information embedded on the other portable device. - View Dependent Claims (2, 3, 4, 5)
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6. A method for determining an approximate current time using a first portable device and a second portable device, the first portable device having a first storage device, the second portable device having a second storage device, the first storage device storing thereon a first sequence number and a first key, the second storage device storing thereon a second sequence number and a second key, wherein the first and second sequence numbers comprise information on a first and a second trusted time embedded in the respective storage devices, the method comprising the steps of:
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comparing the first sequence number to the second sequence number, the first sequence number being indicative of the first trusted time provided on the first portable device, the second sequence number being indicative of the second trusted time provided on the second portable device; if the second trusted time is newer than the first trusted time, performing a verification using at least one of the first and second keys; and setting the first sequence number to have a value of the second sequence number if the verification succeeds; and
conversely,if the first trusted time is newer than the second trusted time, performing a verification using at least one of the first and second keys; and setting the second sequence number to have a value of the first sequence number if the verification succeeds so that the older trusted time information embedded on one of two portable devices is mutually replaced with the newer trusted time information embedded on the other portable device. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification