Secure video decoder system

• US 5,018,197 A
• Filed: 07/30/1990
• Issued: 05/21/1991
• Est. Priority Date: 07/30/1990
• Status: Expired due to Term

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: Zenith Electronics Corporation (LG Corporation)
• Inventors: Jones, Gary A., Krishnamurthy, Gopalan, Snopko, Paul A.
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US07/559,468
• Time in Patent Office: 295 Days
• Field of Search: 380/16, 380/10, 380/20, 380/21, 380/49, 380/52
• US Class Current: 380/239
• CPC Class Codes: H04N 7/1675 Providing digital key or authorisation information for generation or regeneration of the scrambling sequence pseudo-random number generators in general G06F7/58

Abstract

A video decoder includes an application specific integrated circuit (ASIC) that has the decoder address and a secure decryption key stored in a one-time-programmable memory. Encrypted messages are received and selectively supplied to a packet decrypter and to a video decrypter based upon the location of bits in the message string. The packet decrypter is responsive to a flag in the packet data for utilizing a secure key or a unsecure key for decryption of the packet data. The information derived from the secure decryption and the secure key itself are never available (or ascertainable) outside of the ASIC. Only information concerning the unsecure key is available outside of the integrated circuit.

Claims

1. A cable decoder system comprising;

means for receiving message encrypted with a secure decryption key and another decryption key and a scrambled video signal from a cable head end;

means for supplying said encrypted messages to an integrated circuit;

means in said integrated circuit for storing said secure decryption key and said another decryption key;

means in said integrated circuit for decrypting said messages with said secure decryption key for enabling descrambling of said scrambled video signal;

means in said integrated circuit for decrypting portions of said received messages that are encrypted with said another decryption key; and

means for permitting signals exiting said integrated circuit to only reflect said another decryption key.

2. The decoder of claim 1 wherein said messages include packet information and video information and wherein said packet information is encrypted partially with a secure decryption key and encrypted partially with an unsecure decryption key.

3. A cable decoder system comprising;

means for receiving messages including secure data encrypted with a secure decryption key and unsecure data encrypted with an unsecure decryption key and a scrambled video signal from a cable head end;

means for supplying said encrypted messages to an integrated circuit;

means in said integrated circuit for storing said secure decryption key and said unsecure decryption key;

means in said integrated circuit for decrypting said secure data with said secure decryption key for enabling descrambling of said scrambled video signal;

means in said integrated circuit for decrypting said unsecure data with said unsecure decryption key; and

means for permitting signals exiting said integrated circuit to only reflect said unsecure decryption key.