Revocation of anonymous certificates, credentials, and access rights

1. A method for revocation of a derived credential formed from an initial credential and an indication value at a credential-granting service, the method comprising

creating an archive at the credential-granting service for storage of prime number values that are associated with membership certificates of respective user devices whose credentials have been revoked;

identifying a user device whose privileges are to be revoked;

retrieving the prime number value that is associated with the membership certificate of the identified user device;

updating an accumulator value utilizing the retrieved prime number value; and

storing the retrieved prime number value at the archive dedicated to the storage of prime number values that are associated with user devices whose credentials have been revoked.

2. The method of claim 1 , further comprising connecting the user device to the credential-granting service by sending activation information from the credential-granting service to the user device in order to obtain a credential, the activation information comprising an initial credential and an indication value.

3. The method of claim 2 , wherein updating the accumulator value comprises replacing the accumulator value by an updated accumulator value provided by the credential-granting service, the updated accumulator value including currently valid user credential keys.

4. A system for provision and revocation of derived credentials formed from initial credential and indication values within a network, the system comprising:

a user device connectable to a credential-granting service and an entity, the credential-granting service having an update unit for an accumulator value based on a plurality of user credential keys where each user credential key is associated with one user device entitled to the derived credentials, the credential-granting service providing public information having a public key for verifying the initial credential and the accumulator value wherein the update unit is adapted to update the accumulator value by an accumulator so as to include currently valid user credential keys, and

the credential-granting service comprising an archive for storage of prime number values that are associated with membership certificates of respective user-device's whose credentials have been revoked, where in the event of the revocation of a user-device's membership certificate the credential-granting service is further responsible for retrieving the prime number value that is associated with the membership certificate of an identified user device and updating the accumulator value utilizing the retrieved prime number value and storing the retrieved prime number value at the archive.

5. The system according to claim 4 , wherein the entity and the credential-granting service are integrated in a unitary entity.

6. The system of claim 4 , wherein the user device is adapted to send a derived-credential information comprising an initial-credential information and an indication-value information indicating that the user credential key is inherently included in the accumulator value, and request information.

7. The system of claim 6 , wherein the entity is adapted to process the request information in response to a verification that the initial-credential information and the indication-value information are valid.

8. A system that comprises a provider, the provider being utilized for the provision and revocation of derived credentials that have been formed from initial credential and indication values within a network, the provider further comprising:

a user device connectable to a credential-granting service and an entity, the credential-granting service having an update unit for an accumulator value based on a plurality of user credential keys where each user credential key is associated with one user device entitled to the derived credential, the credential-granting service providing public information having a public key for verifying the initial credential and the accumulator value, wherein:

the update unit is adapted to update the accumulator value by an accumulator so as to include currently valid user credential keys, where in the event of the revocation of a user-device's membership certificate the update unit is further responsible for retrieving a prime number value that is associated with the membership certificate of an identified user device and updating the accumulator value utilizing the retrieved prime number value.

9. A computer program product that includes a computer readable medium useable by a processor, the medium having stored thereon a sequence of instructions which, when executed by the processor, causes the processor to revoke a derived credential formed from an initial credential and an indication value within credential-granting service, by:

creating an archive at a credential-granting service for storage of prime number values that are associated with the membership certificates of respective user devices whose derived credentials have been revoked;

identifying a user device whose privileges are to be revoked;

retrieving the prime number value that is associated with the membership certificate of the identified user device;

updating an accumulator value utilizing the retrieved prime number value;

and storing the retrieved prime number value at the archive.