The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 09, 2012
Filed:
May. 24, 2010
David F. Pare, San Francisco, CA (US);
David L. Biderman, San Francisco, CA (US);
Stephen E. Loomis, Leesburg, VA (US);
Scott K. Brown, Ashburn, VA (US);
Michael Wise, Washington, DC (US);
David Wexelblat, Vienna, VA (US);
Conor P. Cahill, Waterford, VA (US);
David S. Bill, San Francisco, CA (US);
David F. Pare, San Francisco, CA (US);
David L. Biderman, San Francisco, CA (US);
Stephen E. Loomis, Leesburg, VA (US);
Scott K. Brown, Ashburn, VA (US);
Michael Wise, Washington, DC (US);
David Wexelblat, Vienna, VA (US);
Conor P. Cahill, Waterford, VA (US);
David S. Bill, San Francisco, CA (US);
Facebook, Inc., Menlo Park, CA (US);
Abstract
An initialization vector (IV) is employed to decrypt a block of a stream that has been encrypted with Cypher Block Chaining (CBC) encryption, without requiring decryption of previous blocks within the stream. For example, a listener who accesses a distribution point to retrieve encrypted content authenticates himself to an application server that regulates access to encrypted content on the distribution point, and responsively receives a key. The listener then requests access to a reference point within the encrypted content stream somewhere after its beginning (e.g., using preview clips). The distribution point relates the reference point to a corresponding block of the encrypted stream, and identifies an IV previously used for encryption of that block. The distribution point provides the associated encrypted block of content and the IV to the listener to enable mid-stream rendering of the encrypted content, without requiring the listener to decrypt previous blocks within the encrypted stream.