France Telecom

Orange

Laurent Frisch

Dimitri Mouton

David Arditti Modiano

David Arditi

Sylvie Camus

Benoît De Boursetty

For signing of data by a given one of M delegates mandated by N titleholders, where M&#x2267;2 and N=1 or M=1 and N&#x2267;2, the terminal of the given delegate reads in a delegation server information on the delegates and the titleholders of the group thus constituted. The data and the information read and a private key of the given delegate are applied to a cryptographic algorithm to produce a signature which therefore carries a cryptographic delegation mark. The data, information, and signature are transmitted to a user terminal that can trace the characteristics of the signature delegation.

Delegation of electronic signature by multi-agent cryptography

A ring-signature scheme is adapted so that at least one of the variability parameter values used is an identity trace of the anonymous signatory, determined as a function of anonymity withdrawal data stored and held secret by an anonymity withdrawal entity in connection with an identification of the anonymous signatory. This provides a subsequent controlled capacity of withdrawing the anonymity of the signatory, either by an authority, or by the signatory himself.

Electronic group signature method with revocable anonymity, equipment and programs for implementing the method

The cryptographic resources are supplied by at least one cryptographic source having a specific access interface. The application is presented with a mutualized interface substantially independent of the cryptographic sources and of their respective access interfaces. A translation module is placed between the mutualized interface and each interface for accessing a cryptographic source to provide access to the cryptographic resources from the application via the mutualized interface.

Method of controlling access to cryptographic resources

In order to apply an electronic signature from a client station having authentication resources at a server, the following steps are carried out: the client station is authenticated at the server, thus establishing an authenticated communication channel; a private key/public key pair is generated at the client station; a signature certificate request generated by means of at least the public key is transmitted from the client station to the server via the authenticated channel; a signature certificate obtained in response to the request is returned via the authenticated channel; this certificate is verified at the client station; an electronic signature is calculated at the client station by means of the private key, after which this private key is destroyed; and the calculated signature is formatted with the aid of the signature certificate received via the authenticated channel.

Growing community of inventors

Paris, France

Laurent Frisch