Method and apparatus for location-sensitive decryption of an encrypted signal

• US 6,317,500 B1
• Filed: 06/16/1997
• Issued: 11/13/2001
• Est. Priority Date: 04/28/1995
• Status: Expired due to Term

• Current Assignee: Trimble Navigation Limited (Trimble Inc.)
• Original Assignee: Trimble Navigation Limited (Trimble Inc.)
• Inventors: Murphy, Michael D.
• Primary Examiner(s): Hayes, Gail
• Assistant Examiner(s): Seal, James
• Application Number:
  US08/878,246
• Time in Patent Office: 1,611 Days
• Field of Search: 380/5, 380/20, 380/3, 380/4, 380/10, 380/23, 380/49, 380/21, 380/258, 701/213, 342/357.07, 342/357.12
• US Class Current: 380/258
• CPC Class Codes: H04N 21/4524 involving the geographical location of the client retrieval from the Internet by querying based on geographical locations G06F16/9537; systems specially adapted for using geographical information in broadcast systems H04H60/70; protocols in which the network application is adapted for the location of the user terminal in communication control or processing H04L67/52; services making use of the location of users or terminals in wireless networks H04W4/02; locating users or terminals in wireless networks H04W64/00
• CPC Class Codes: H04N 7/165 Centralised control of user terminal subsequent to an upstream request signal H04N7/17345; Registering at central by two-way working H04N7/17309

Abstract

A system for assuring the location integrity of a decryption chip used to receive and decrypt encrypted signals ES received from an encrypted signal source. The decryption chip operates in association with a licensed signal receiver and is licensed for use at a selected site or location L_i and is positioned adjacent to a Satellite Positioning System (SATPS) antenna and receiver/processor that determine the present location L of this antenna. If the SATPS-determined location L is within a region R(L_i;d_i), centered at the location L_i and having a selected diameter d_i, and if the signal ES is associated with a channel that is authorized for reception by this signal receiver, the decryption chip is enabled, and the signal ES is decrypted for audible or visual display on the signal receiver. Otherwise, the decryption chip does not decrypt the incoming signal ES. The licensed site location L_i can be changed and the group of channels for which signal receipt and decryption is authorized can be changed. This system can operate on encrypted television signals and other similar signals. The SATPS may be a Global Positioning System (GPS) or a Global Orbiting Navigational Satellite System (GLONASS), or another suitable satellite-based location determination system.

Claims

1. A method for decrypting an encrypted signal, the method comprising the steps of:

a) providing a module that includes a Satellite Positioning System location determination unit and that includes a decryption chip, said Satellite Positioning System location determination unit coupled to said decryption chip;

b) storing, within said module, a collection of location coordinates that defines a selected region within which said decryption chip is to be enabled;

c) determining location of said module using said Satellite Positioning System location determination unit;

d) comparing said determined location to said collection of location coordinates for determining whether said determined location is within said selected region within which said decryption chip is to be enabled;

e) receiving an external signal at said module that is encrypted; and

f) decrypting said signal that is encrypted using said decryption chip when the comparison in step d) determines that said determined location is within said selected region within which said decryption chip is to be enabled.

2. A module for receiving and decrypting encrypted signals, the module comprising:

means for receiving a signal including a signal receiver that can receive an encrypted signal from an encrypted signal source;

means for location determination including a SATPS location determination unit for determining location;

means for data storage for storing, within said module, a collection of location coordinates that defines a selected region within which said module is to be enabled;

means for decryption coupled to said signal receiving means and coupled to said location determining means and coupled to said data storage means for decrypting an encrypted signal received by said signal receiving means when the location determined by said location determination means is within said selected region within which said module is to be enabled.

3. A method for decrypting an encrypted signal, the method comprising the steps of:

a) providing a module that includes a Satellite Positioning System location determination unit and that includes a decryption chip, said Satellite Positioning System location determination unit coupled to said decryption chip;

b) storing, within said module, a collection of location coordinates that defines a selected region within which said decryption chip is to be enabled;

c) determining location of said module using said Satellite Positioning System location determination unit;

d) comparing said determined location to said collection of location coordinates for determining whether said determined location is within said selected region within which said decryption chip is to be enabled;

e) receiving an external signal at said module, said signal including at least one channel that is encrypted; and

f) decrypting said channel that is encrypted using said decryption chip when the comparison in step d) determines that said determined location is within said selected region within which said decryption chip is to be enabled.