Method and system for checking digital signatures and card with microcircuit for using the method
First Claim
1. A method for checking a digital signature, involving a microcircuit connectable to a data processing system, the microcircuit being designed to receive requests to check digital signatures from the data processing system, and to process these requests, a digital signature being generated using a private key only known to a signatory entity and associated with a public key, said method comprising:
- a step of storing a certificates table containing a digest form of at least one public key in a memory in the microcircuit, wherein the public key is inserted into the certificates table by a step that comprises inserting, in the certificates table, a pointer to the digest form of the public key of the certification entity that issued the certificate of the public key, so as to define a certification tree in combination with the inserted digest form of the public key; and
a phase of checking a digital signature comprising steps of;
receiving by the microcircuit a digital signature to be checked and a public key in a pair of keys comprising a private key that was used to generate the digital signature to be checked;
calculating a digest form of the received public key;
searching for the calculated digest form of the public key in the microcircuit'"'"'s certificates table, at a location at which the inserted pointer points; and
decrypting the digital signature using the received public key if the calculated digest form of the public key is located in the certificates table.
1 Assignment
0 Petitions
Accused Products
Abstract
To check a digital signature, using a microcircuit card, the microcircuit being designed to receive and to process requests to check digital signatures, the process comprises storing in a memory in the microcircuit a certificates table containing digest forms of authorized public keys, and a phase of checking a digital signature consisting of: receiving by the microcircuit the digital signature to be checked and a public key corresponding to a private key that was used to generate the digital signature to be checked; calculating a digest form of the received public key, searching for the calculated digest form of the public key in the certificates table, and decrypting the digital signature using the received public key if the calculated digest form of the public key is located in the certificates table.
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Citations
22 Claims
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1. A method for checking a digital signature, involving a microcircuit connectable to a data processing system, the microcircuit being designed to receive requests to check digital signatures from the data processing system, and to process these requests, a digital signature being generated using a private key only known to a signatory entity and associated with a public key, said method comprising:
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a step of storing a certificates table containing a digest form of at least one public key in a memory in the microcircuit, wherein the public key is inserted into the certificates table by a step that comprises inserting, in the certificates table, a pointer to the digest form of the public key of the certification entity that issued the certificate of the public key, so as to define a certification tree in combination with the inserted digest form of the public key; and a phase of checking a digital signature comprising steps of; receiving by the microcircuit a digital signature to be checked and a public key in a pair of keys comprising a private key that was used to generate the digital signature to be checked; calculating a digest form of the received public key; searching for the calculated digest form of the public key in the microcircuit'"'"'s certificates table, at a location at which the inserted pointer points; and decrypting the digital signature using the received public key if the calculated digest form of the public key is located in the certificates table. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A microcircuit being designed to receive requests to check digital signatures from the data processing system, and to process these requests, a digital signature being generated using a private key only known to a signatory entity and associated with a public key, said microcircuit comprising:
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memory means for storing a certificates table containing a digest form of at least one public key, wherein the public key is insertable into the certificates table by means for inserting, in the certificates table, a pointer to the digest form of the public key of the certification entity that issued the certificate of the public key, so as to define a certification tree in combination with the inserted digest form of the public key; means for receiving a digital signature to be checked and a public key in a pair of keys comprising a private key that was used to generate the digital signature to be checked; means for calculating a digest firm of the received public key, and for searching for the calculated digest form of the public key in the certificates tables; and means for decrypting the digital signature using the received public key if the calculated digest form of the public key is located in the certificates table. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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Specification