System and method for using a streaming protocol

US8634552B2 · kind B2 · utility

Assignee

• AOl · US

Inventors

• David F. Pare · Berkeley, US
• David L. Biderman · San Jose, US
• Stephen Loomis · Leesburg, US
• Scott K. Brown · Marietta, US
• Michael Wise · Washington, US
• David Wexelblat · Vienna, US
• Conor P. Cahill · Waterford, US
• David S. Bill · San Francisco, US

Key dates

• Filing date: Oct 9, 2009
• Grant date: Jan 21, 2014
• Expiry date: Feb 17, 2032

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04L67/60
• WIPO field: Digital communication
• WIPO sector: Electrical engineering

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.