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:
Sep. 20, 2011
Filed:
Oct. 09, 2007
Richard Doherty, Northridge, CA (US);
Robert Hughes, Seattle, WA (US);
Richard Doherty, Northridge, CA (US);
Robert Hughes, Seattle, WA (US);
Microsoft Corporation, Redmond, WA (US);
Abstract
A modified media key used to decrypt protected media content stored on an optical disc, such as an HD-DVD or Blu-ray disc, is created through application of a transformation using a constant value which is programmatically generated by procedural code that runs on a player. The transformation is obfuscated through application of a random value to the constant value through a logical XOR operation. The programmatically-generated constant, called Soft Key Conversion Data ('SKCD') is used by a security layer to derive the modified media key, called a Soft Media Key. At the player, a conventionally calculated media key is used to decrypt the first title, while the Soft Media Key is used to decrypt subsequent titles. Optionally, the SKCD may be updated one or more times so that the Soft Media Key is repeatedly transformed and respectively applied, for example, on a title-by-title basis, or to groups of subsequent titles.