Patents by Inventor Rafik Chaabouni

Rafik Chaabouni has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 9083535
    Abstract: A method for providing efficient management of certificate revocation may comprise storing a list of identifiers of digital certificates including a revocation list defining a list of revoked certificates in an accumulator, storing a witness value in association with at least some entries in the revocation list in which the witness value provides proof of the membership or non-membership of an identifier in the revocation list, enabling generation of a new accumulator and a new witness value responsive to each insertion or deletion of an entry in the revocation list, and enabling batch updates to the revocation list using a reduced bitlength value generated based on to a ratio of a value generated based on elements added to the revocation list to a value generated based on elements deleted from the revocation list. A corresponding apparatus is also provided.
    Type: Grant
    Filed: November 5, 2010
    Date of Patent: July 14, 2015
    Assignee: Nokia Corporation
    Inventors: Atefeh Mashatan, Imad Aad, Rafik Chaabouni, Pentti Valtteri Niemi, Serge Vaudenay
  • Publication number: 20130238897
    Abstract: A method for providing efficient management of certificate revocation may comprise storing a list of identifiers of digital certificates including a revocation list defining a list of revoked certificates in an accumulator, storing a witness value in association with at least some entries in the revocation list in which the witness value provides proof of the membership or non-membership of an identifier in the revocation list, enabling generation of a new accumulator and a new witness value responsive to each insertion or deletion of an entry in the revocation list, and enabling batch updates to the revocation list using a reduced bitlength value generated based on to a ratio of a value generated based on elements added to the revocation list to a value generated based on elements deleted from the revocation list. A corresponding apparatus is also provided.
    Type: Application
    Filed: November 5, 2010
    Publication date: September 12, 2013
    Inventors: Atefeh Mashatan, Imad Aad, Rafik Chaabouni, Pentti Valtteri Niemi, Serge Vaudenay
  • Patent number: 8015398
    Abstract: A method and apparatus for proving and a method and apparatus for verifying that a secret value is a member of a predetermined set of values. The proving mechanism receives a set of signatures which has respective values in the predetermined set signed using a private key. The proving mechanism sends to the verifying mechanism a commitment on the secret value of the proving mechanism. The proving mechanism and verifying mechanism then communicate to implement a proof of knowledge protocol demonstrating knowledge by the proving mechanism of a signature on the secret value committed to in the commitment, thus proving that the secret value is a member of the predetermined set.
    Type: Grant
    Filed: December 5, 2008
    Date of Patent: September 6, 2011
    Assignee: International Business Machines Corporation
    Inventors: Jan Leonhard Camenisch, Rafik Chaabouni, Abhi A. Shelat
  • Publication number: 20090300347
    Abstract: A method and apparatus for proving and a method and apparatus for verifying that a secret value is a member of a predetermined set of values. The proving mechanism receives a set of signatures which has respective values in the predetermined set signed using a private key. The proving mechanism sends to the verifying mechanism a commitment on the secret value of the proving mechanism. The proving mechanism and verifying mechanism then communicate to implement a proof of knowledge protocol demonstrating knowledge by the proving mechanism of a signature on the secret value committed to in the commitment, thus proving that the secret value is a member of the predetermined set.
    Type: Application
    Filed: December 5, 2008
    Publication date: December 3, 2009
    Inventors: Jan Leonhard Camenisch, Rafik Chaabouni, Abhi A. Shelat