Xin Wang

US Patent:

6519700, Feb 11, 2003

Filed:

Oct 23, 1998

Appl. No.:

09/178529

Inventors:

Prasad Ram - Manhattan Beach CA
Thanh T. Ta - Huntington Beach CA
Xin Wang - Los Angeles CA

Assignee:

Contentguard Holdings, Inc. - Wilmington DE

International Classification:

C06F 1216

US Classification:

713193, 713160, 380 45, 380201, 705 51, 705 57

Abstract:

A system and method for the secure distribution of electronic documents reduces the likelihood of unauthorized reproduction and redistribution by either authorized or unauthorized recipients. A self-protecting document (SPD) contains an encrypted document as well as a secure set of permissions and the software necessary to process the document; full decryption of the document is performed as late as possible so as to minimize the possibility of intercepting the document before it has been fully rendered to screen or to paper.

US Patent:

6763464, Jul 13, 2004

Filed:

Jul 18, 2002

Appl. No.:

10/196953

Inventors:

Xin Wang - Los Angeles CA
Thanh T. Ta - Huntington Beach CA
Prasad Ram - Manhattan Beach CA

Assignee:

ContentGuard Holdings, Inc. - Wilmington DE

International Classification:

G06F 1216

US Classification:

713193, 713160, 380 45, 380201, 705 51, 705 57

Abstract:

A system and method for the secure distribution of electronic documents reduces the likelihood of unauthorized reproduction and redistribution by either authorized or unauthorized recipients. A self-protecting document (SPD) contains an encrypted document as well as a secure set of permissions and the software necessary to process the document; full decryption of the document is performed as late as possible so as to minimize the possibility of intercepting the document before it has been fully rendered to screen or to paper.

US Patent:

6859533, Feb 22, 2005

Filed:

Dec 21, 1999

Appl. No.:

09/469487

Inventors:

Xin Wang - Los Angeles CA, US
Thanh T. Ta - Huntington Beach CA, US

Assignee:

ContentGuard Holdings, Inc. - Wilmington DE

International Classification:

H04L009/28

US Classification:

380 28, 380259

Abstract:

Methods for transferring among key holders in encoding and cryptographic systems the right to decode and decrypt messages in a way that does not explicitly reveal decoding and decrypting keys used and the original messages. Such methods are more secure and more efficient than typical re-encoding and re-encryption schemes, and are useful in developing such applications as document distribution and long-term file protection.

US Patent:

6885748, Apr 26, 2005

Filed:

Mar 24, 2000

Appl. No.:

09/536089

Inventors:

Xin Wang - Los Angeles CA, US

Assignee:

ContentGuard Holdings, Inc. - Wilmington DE

International Classification:

H04N007/167
H04L009/00

US Classification:

380201, 380212, 713160, 713193, 705 51, 705 57

Abstract:

A method of protecting a digital work uses a format preserving encryption scheme to encrypt the digital work. This enables any native replay application or rendering application to transform an encrypted digital work into encrypted presentation data. The originator's digital content is protected in its original form by not being decrypted. This method enables the rendering or replay application to process the encrypted document into encrypted presentation data without decrypting it first. Encrypted presentation data is then decrypted just before it is displayed to the user. An additive encryption scheme is a particular type of encryption scheme which preserves formatting of a digital work.

US Patent:

6912294, Jun 28, 2005

Filed:

Dec 29, 2000

Appl. No.:

09/749895

Inventors:

Xin Wang - Los Angeles CA, US
Steve Atsushi Okamoto - Torrance CA, US
Russell Robert Lear - Torrance CA, US
Nancy Lynn Ishigo - Torrance CA, US

Assignee:

ContentGuard Holdings, Inc. - Wilmington DE

International Classification:

G06K009/00

US Classification:

382100, 713176

Abstract:

A multi-stage watermarking system and process that creates a watermark specification which describes how to generate a watermark, generates a template specification which describes how to merge the watermark into a target document, generates the watermark based on the watermark specification, and merges the watermark into the target document based on the template specification to provide a watermarked document.

US Patent:

6931545, Aug 16, 2005

Filed:

Aug 28, 2000

Appl. No.:

09/649838

Inventors:

Thanh Ta - Huntington Beach CA, US
Xin Wang - Los Angeles CA, US

Assignee:

ContentGuard Holdings, Inc. - Wilmington DE

International Classification:

G06F011/30
G06F012/14
H04L009/32
H04L009/00

US Classification:

713200, 713156, 713187

Abstract:

A content provider, such as a document publisher or distributor, provides, for example, protected content to a user, for consumption within a trusted user environment. By providing integrity certification and verification services, the authenticity of the content consumption environments can be verified. The content provider forwards to the user a protected version of the digital content which includes, for example, a license agreement and an integrity profile identification. The profile includes, for example, the applications and system components that are allowed to be used in conjunction with the protected content. Additionally, the content provider initiates a request for an integrity profile. This request for the integrity profile is forwarded to an integrity certification and verification device. The integrity certification and verification device can, for example, if an integrity profile does not already exist for the requested applications and/or systems components, query a content consumption system/application provider, who, for example, has supplied the system components to the user.

US Patent:

6937726, Aug 30, 2005

Filed:

Dec 21, 1999

Appl. No.:

09/468747

Inventors:

Xin Wang - Los Angeles CA, US

Assignee:

ContentGuard Holdings, Inc. - Wilmington DE

International Classification:

H04L009/00
H04K001/00

US Classification:

380 30, 380 28, 380 44, 380273, 380277

Abstract:

Methods for transferring among key holders in encoding and cryptographic systems the right to decode and decrypt messages in a way that does not explicitly reveal decoding and decrypting keys used and the original messages. Such methods are more secure and more efficient than typical re-encoding and re-encryption schemes, and are useful in developing such applications as document distribution and long-term file protection.

US Patent:

6963858, Nov 8, 2005

Filed:

Dec 11, 2002

Appl. No.:

10/316187

Inventors:

Xin Wang - Torrance CA, US
Eddie J. Chen - Rancho Palos Verdes CA, US
Thomas DeMartini - Culver City CA, US
Charles P. Gilliam - Darien CT, US
Guillermo Lao - Torrance CA, US
Aram Nahidipour - Laguna Niguel CA, US
Michael Raley - Downey CA, US
Thanh Ta - Huntington Beach CA, US
Bijan Tadayon - Germantown MD, US

Assignee:

ContentGuard Holdings, Inc. - Wilmington DE

International Classification:

G06F017/60

US Classification:

705 51, 707 9, 707104

Abstract:

A rights management system including one or more consequential rights associated with digital content, and specifying a manner of use of the digital content, a right management module that enforces the rights permitting use of the digital content in accordance with the rights upon occurrence of a consequential event. The consequential event is based on another usage right. In one embodiment, the consequential event is the exercise, expiration, or possession of another usage right.