Method and system for generating keys for an anonymous signature scheme

A method for generating keys for an anonymous signature scheme, said method comprising:

• calculating by at least one revocation entity a pair of revocation keys comprising a public key and a private key, said private key being usable by said revocation entity to revoke the anonymity of an anonymous signature complying with said scheme;
• registering by a group administration entity at least one member entity with said group;
• calculating, from the public key of said at least one pair of revocation keys, a trace generator, said trace generator being intended to be used by each said member entity to generate a trace representative of said member entity, said trace being invariant relative to the anonymous signatures generated by said member entity in accordance with said scheme;
• and
• said member entity blindly obtaining a private group key, said private key used by said member entity to generate anonymous signatures in accordance with said scheme, said anonymous signatures comprising said trace.

A system for generating keys for an anonymous signature scheme, this system comprising:

• at least one revocation entity configured to calculate a pair of revocation keys comprising a public key and a private key, said private key being usable by said revocation entity to revoke anonymity of an anonymous signature complying with said anonymous signature scheme;
• a group administration entity configured to register at least one member entity with said group;
• said at least one revocation entity being configured to calculate, from a public key of said at least one pair of revocation keys, a trace generator, said trace generator being intended to be used by each said member entity to generate a trace representative of said member entity, said trace being invariant relative to the anonymous signatures generated by said member entity in accordance with said scheme;
• and
• said at least one member entity, which is configured to blindly obtain a private group key, said private key being used by said member entity to generate anonymous signatures complying with said scheme, said anonymous signatures comprising said trace.

An anonymous signature device of a message executed by a member entity of a group and comprising:

• a processor;
• and
• a non-transitory computer-readable medium comprising instructions stored thereon which when executed by the processor configure the anonymous signature device to:
• register said member entity with an administration entity of the group;
• generate a trace from a trace generator calculated by at least one revocation entity and included in a public key of said group, said trace being invariant relative to the anonymous signatures generated by said member entity in accordance with said scheme;
• blindly obtain a private group key;
• and
• generate the anonymous signatures by using said private group key, said signatures comprising said trace.