Method for certifying the origin of at least one item of information

Abstract

The object of the invention is a process for certifying the origin of at least one item of information stored in the memory of a first electronic device such as a portable card and transmitted to a second electronic device such as a portable card, and a system for implementing said process. An individual A controls a card C.sub.A which has a memory M.sub.A that contains an item of information I.sub.A specific to the individual A. An individual B controls a card C.sub.B which has a memory M.sub.B that contains an item of information I.sub.B specific to individual B. In order for individual B, who receives the information I.sub.A, to be certain of the origin of this information I.sub.A, each of the two cards C.sub.A and C.sub.B calculates a result R related to the information I.sub.A, to a secret set (S) shared by the two cards, to a random number (E.sub.B) supplied by individual B, and to a parameter J which, in turn, is related to the two items of information (I.sub.A, I.sub. B) which are combined in accordance with a predetermined symmetrical algorithm p. The invention applies in particular to mutual identification and certification between two individuals of the same group who have been issued individual cards. Each individual of the group is issued his own personal card.