Patents by Inventor David W. Kravitz

David W. Kravitz 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).

  • Publication number: 20110083189
    Abstract: A method for enforcing digital rights management (DRM) rules in a first device is disclosed. In the method the first device receives a message that includes a rights object (RO) having a digital signature, directly from a source device. The first device determines an identity of a signing entity from the message including the RO having the digital signature. The signing entity is an entity that digitally signed the RO. The first device processes the message including the RO having the digital signature using the identity of the signing entity and an information state to enforce DRM rules in the first device.
    Type: Application
    Filed: October 6, 2009
    Publication date: April 7, 2011
    Applicant: MOTOROLA, INC.
    Inventor: David W. Kravitz
  • Publication number: 20100306548
    Abstract: In a method for enabling support for backwards compatibility in a User Domain, in one of a Rights Issuer (RI) and a Local Rights Manager (LRM), a Rights Object Encryption Key (REK) and encrypted REK are received from an entity that generated a User Domain Authorization for the one of the RI and the LRM and the REK is used to generate a User Domain Rights Object (RO) that includes the User Domain Authorization and the encrypted REK.
    Type: Application
    Filed: June 2, 2009
    Publication date: December 2, 2010
    Applicant: MOTOROLA, INC.
    Inventor: David W. Kravitz
  • Publication number: 20090025061
    Abstract: A method, apparatus, and electronic device for protecting digital rights are disclosed. A network interface may receive a rights representation for a set of digital content from a source entity. A processor may conditionally accept the set of digital content. A memory may store a local blacklist identifying the source entity if a rights event occurs.
    Type: Application
    Filed: July 17, 2007
    Publication date: January 22, 2009
    Applicant: Motorola, Inc.
    Inventor: David W. KRAVITZ
  • Patent number: 6738905
    Abstract: A method and apparatus for distributing content data from a content provider to a subscriber. The method includes encrypting content data by the content provider and providing the content data from the content provider to a broadcaster. The content provider also provides a content descriptor, including keys to decrypt the encrypted content, to a conditional access provider. The broadcaster distributes the encrypted content information to a subscriber. A business service provider negotiates with the subscriber to deliver individual content programs or packages of content programs to the subscriber for a fee. The conditional access provider distributes a content descriptor including keys necessary to decrypt the programs the subscriber selected from the business service provider. A CAM retained by the subscriber maintains a log of programs accessed, and uploads the log to the business service provider, which is used to determine the appropriate fee which the subscriber should be charged.
    Type: Grant
    Filed: April 14, 1999
    Date of Patent: May 18, 2004
    Assignee: Digital Video Express, L.P.
    Inventors: David W. Kravitz, David M. Goldschlag
  • Publication number: 20010011220
    Abstract: A method for providing a warranty relating to a transaction between two parties, each party having a data communications device, in a system which includes an infrastructure composed of a plurality of locations each associated with a respective institution which provides services to clients, each location having a computer system, a database coupled to the computer system and storing information about each client of the institution and a data communications device coupled to the computer system for communication with the data communications device of any one party, each party being a client of at least one of the institutions, the method containing the steps of:
    Type: Application
    Filed: February 19, 1998
    Publication date: August 2, 2001
    Inventors: YAIR FRANKEL, DAVID W. KRAVITZ, CHARLES T. MONTGOMERY, MOTI YUNG
  • Patent number: 5995625
    Abstract: A method of unwrapping wrapped digital data that is unusable while wrapped, includes obtaining an acceptance phrase from a user; deriving a cryptographic key from the acceptance phrase; and unwrapping the package of digital data using the derived cryptographic key. The acceptance phrase is a phrase entered by a user in response to information provided to the user. The information and the acceptance phrase can be in any appropriate language. The digital data includes, alone or in combination, any of: software, a cryptographic key, an identifying certificate, an authorizing certificate, a data element or field of an identifying or authorizing certificate, a data file representing an images, data representing text, numbers, audio, and video.
    Type: Grant
    Filed: March 24, 1997
    Date of Patent: November 30, 1999
    Assignee: Certco, LLC
    Inventors: Frank W. Sudia, Alan Asay, Ernest F. Brickell, Richard Ankney, Peter C. Freund, Marcel M. Yung, David W. Kravitz
  • Patent number: 5832089
    Abstract: An off-line electronic cash system having an electronic coin, a bank B, a payee S, and a user U with an account at the bank B as well as a user password z.sub.u,i, has a method for performing an electronic cash transfer. An electronic coin is withdrawn from the bank B by the user U and an electronic record of the electronic coin is stored by the bank B. The coin is paid to the payee S by the user U. The payee S deposits the coin with the bank B. A determination is made that the coin is spent and the record of the coin is deleted by the bank B. A further deposit of the same coin after the record is deleted is determined. Additionally, a determination is made which user U originally withdrew the coin after deleting the record. To perform these operations a key pair is generated by the user, including public and secret signature keys. The public signature key along with a user password z.sub.u,i and a withdrawal amount are sent to the bank B by the user U.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: November 3, 1998
    Assignee: Sandia Corporation
    Inventors: David W. Kravitz, Peter S. Gemmell, Ernest F. Brickell
  • Patent number: 5231668
    Abstract: A method is provided for generating and verifying a digital signature of a message m. This method requires a pair of corresponding public and secret keys (y and x) for each signer, as well as a pair of public and secret values (r and k) generated for each message by the signer. The public value r is calculated according to the rule r=(g.sup.k mod p) mod q. A value s is then selected according to the rule s=k.sup.-1 (H(m)+xr) mod q where H is a known conventional hashing function. The message m, along with the signature (r,s) is then transmitted. When the transmitted signal is received a verification process is provided. The received values of r and s are tested to determine whether they are congruent to 0 mod g. Additionally, r is tested to determine whether it is equal to v mod q, where v is computed from r, s, m and y. For legitimately executed signatures, v=g.sup.k mod p.
    Type: Grant
    Filed: July 26, 1991
    Date of Patent: July 27, 1993
    Assignee: The United States of America, as represented by the Secretary of Commerce
    Inventor: David W. Kravitz