Patent ID: 7657738

Claim:
A list signature method comprising: an organizing phase including, for a reliable authority, defining parameters for implementing an anonymous electronic signature, including a private key and a corresponding public key; a phase of registering persons in a list of members authorized to generate an electronic signature specific to the members of the list, during which each person to be registered, calculates a private key by means of parameters provided by the reliable authority and by parameters randomly selected by the person to be registered, and the reliable authority delivers to each person to be registered, a certificate of membership of the list; a phase of defining a sequence including for the reliable authority, generating a serial number to be used in a signing phase; a signing phase during which a member of the list generates and issues a signature specific to the members of the list, this signature being built so as to contain proof that the member of the list having issued the signature, has a certificate of membership of the list, and a signature element which is common to all the signatures issued by a same member of the list with a same serial number and which contains proof that the serial number was used for generating the signature; a phase of verifying the issued signature, comprising steps of applying a predefined algorithm in order to show proof that the signature was issued by a person having a certificate of membership of the list, and verifying using said signature element that the serial number was used for generating the signature; a phase of revoking a member of the list in order to remove a member from the list, during which the reliable authority removes the member to be removed from the list and updates the parameters for implementing the anonymous electronic signature, in order to take into account the removal of the member from the list; and a phase of updating certificates of the members of the list in order to take into account changes in the composition of the list.