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US 5,862,224 AGranted
Cryptographic process for protection against fraud
AssigneeFrance Telecom
InventorsHenri Gilbert, David Arditti
Life of this patent
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Abstract
A cryptographic process is for protection against fraud. An allocation of a secret key K is made to a card and to an application and an input value R is defined. The card and application calculate the modulo 2 scalar product of binary vectors constituted by words of R and words of K. The application checks whether the result obtained by the card is in agreement with its own result. An exemplary application is low cost cards.
Claims6
Cryptographic process for protecting against fraud in transactions involving a card, held by a user and an application, said process comprising the steps of:
- allocating to the card and to the application a secret key K having k words, each one of said k words having n bits,
- creating an input R, to the card and to the application, said input R having r words, each one of said r words having n bits,
- calculating, by the card, a result S.sub.1 which is a first modulo 2 scalar product of each one of the r words of the input R with each one of the k words of the secret key K, said result S.sub.1 having k.multidot.r bits,
- calculating, by the application, a result S.sub.2 which is a second modulo 2 scalar product of each one of the r words of the input R with each one of the k words of the secret key K, said result S.sub.2 having k.multidot.r bits,
- transmitting, by the card, the result S.sub.1 to the application, and
- verifying, by the application, that the result S.sub.1 is equal to the result S.sub.2.
3 more elements
Dependencies are inferred from the claim text.