Method and apparatus for constructing a set-top box to protect cryptographic capabilities

• US 20050039212A1
• Filed: 08/04/2004
• Published: 02/17/2005
• Est. Priority Date: 12/27/2001
• Status: Abandoned Application

• Current Assignee: Aurora Networks, Inc. (CommScope Holding Company, Inc.)
• Original Assignee: Aurora Networks, Inc. (CommScope Holding Company, Inc.)
• Inventors: Pickens, John, Field, Michael, Lin, Xu Duan, Baran, Paul
• Application Number:
  US10/911,736
• Publication Number:
  US 20050039212A1
• Time in Patent Office: Days
• US Class Current: 725/91
• CPC Class Codes: H04L 63/068 using time-dependent keys, e.g. periodically changing keys cryptographic mechanisms or cryptographic arrangements for controlling usage of secret information H04L9/088
• CPC Class Codes: H04L 63/10 for controlling access to devices or network resources
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/612 for unicast
• CPC Class Codes: H04N 21/2318 using striping
• CPC Class Codes: H04N 21/2326 Scheduling disk or memory reading operations
• CPC Class Codes: H04N 21/23406 involving management of server-side video buffer
• CPC Class Codes: H04N 21/2347 involving video stream encryption
• CPC Class Codes: H04N 21/2362 Generation or processing of Service Information [SI]
• CPC Class Codes: H04N 21/2365 Multiplexing of several video streams
• CPC Class Codes: H04N 21/26606 for generating or managing entitlement messages, e.g. Entitlement Control Message [ECM] or Entitlement Management Message [EMM] arrangements for conditional access to broadcast information or to broadcast-related services H04H60/14
• CPC Class Codes: H04N 21/4347 Demultiplexing of several video streams
• CPC Class Codes: H04N 21/47202 for requesting content on demand, e.g. video on demand
• CPC Class Codes: H04N 21/6405 Multicasting data broadcast and multicast in packet switching networks H04L12/18
• CPC Class Codes: H04N 21/6587 Control parameters, e.g. trick play commands, viewpoint selection
• CPC Class Codes: H04N 7/17318 Direct or substantially direct transmission and handling of requests
• CPC Class Codes: H05K 1/0275 Security details, e.g. tampering prevention or detection
• CPC Class Codes: H05K 1/144 Stacked arrangements of planar printed circuit boards
• CPC Class Codes: H05K 1/185 Components encapsulated in the insulating substrate of the printed circuit or incorporated in internal layers of a multilayer circuit semiconductor chips encapsulated by interconnect and support structures H01L23/5389, H01L24/00
• CPC Class Codes: H05K 2201/10151 Sensor

Abstract

A construction arrangement for a small set-top box to protect cryptographic capabilities and prevent a digital program in clear from being able to be tapped as required by Digital Rights Management protocols. A first layer of sheet metal capable of blocking X-rays, is formed as a shallow pan to hold a set of printed circuit boards. A second layer has a thin epoxy based printed circuit material. A third layer has a printed circuit board with integrated components placed on top of the second layer. A fourth layer has a three layer thin printed circuit board with a first and second metallic layer and holes for large components, such as electrolytic capacitors. A black liquid thermosetting epoxy fills the interstices between the sheet metal layer and the second layer, and between the second layer and the third layer, and between the third layer and the fourth layer, thereby preventing access to exposed circuit trace carrying digital signals in the clear. A connection from the first metallic layer of the fourth printed circuit material layer to a sending circuit and a connection from the second metallic layer so that a short between these two layers sets off an indicator circuit that an attempt is made to enter the protected area.

Claims

1-28. -28. (canceled)

29. A construction arrangement for a small set-top unit to protect cryptographic capabilities and prevent a digital program in clear from being able to be tapped as required by Digital Rights Management protocols, comprising:

a first layer of sheet metal capable of blocking X-rays, formed as a shallow pan to hold a set of printed circuit boards;

a second layer having a thin epoxy based printed circuit material;

a third layer having a printed circuit board with integrated components placed on top of the second layer;

a fourth layer having a three layer thin printed circuit board with a first and second metallic layer and holes for large components, such as electrolytic capacitors;

a black liquid thermosetting epoxy filling the interstices between the sheet metal layer and the second layer, and between the second layer and the third layer, and between the third layer and the fourth layer, thereby preventing access to exposed circuit trace carrying digital signals in the clear; and

a connection from the first metallic layer of the fourth printed circuit material layer to a sending circuit and a connection from the second metallic layer so that a short between these two layers sets off an indicator circuit that an attempt is made to enter the protected area.

30. The construction arrangement for a small set-top unit as set forth in claim 29, further comprising:

a tamper detector having a sensor wire running along sides of chips containing sensitive information, said sensor wire including four wires, A, B, C, D, twisted together, with a far-end of the four wires terminating A and B in a first short circuit, and separately, C and D in a second short circuit; and

a four-wire connector terminating a near end of the four wires.

31. The construction arrangement for a small set-top unit as set forth in claim 29, further comprising:

circuitry for detecting the first short circuit between the A and B wires, and the second short circuit between the C and D wires, for when the first short circuit or the second short circuit become an open circuit.

32. The construction arrangement for a small set-top unit as set forth in claim 29, further comprising:

circuitry for detecting any cuts in the A and B wires, or in the C and D wires.

33-34. -34. (canceled)

35. A method for constructing a small set-top unit to protect cryptographic capabilities and prevent a digital program in clear from being able to be tapped, comprising the steps of:

constructing a first layer of sheet metal capable of blocking X-rays, formed as a shallow pan to hold a set of printed circuit boards;

making a second layer having a thin epoxy based printed circuit material;

making a third layer having a printed circuit board with integrated components placed on top of the second layer;

a fourth layer having a three layer thin printed circuit board with a first and second metallic layer and holes for large components, such as electrolytic capacitors;

filling, with a liquid thermosetting epoxy, the interstices between the sheet metal layer and the second layer, and between the second layer and the third layer, and between the third layer and the fourth layer, thereby preventing access to exposed circuit trace carrying digital signals in the clear; and

attaching a connection from the first metallic layer of the fourth printed circuit material layer to a sending circuit and a connection from the second metallic layer so that a short between these two layers sets off an indicator circuit that an attempt is made to enter the protected area.

36. The method for constructing a small set-top unit as set forth in claim 35, further comprising the steps of:

installing a tamper detector having a sensor wire running along sides of chips containing sensitive information, said sensor wire including four wires, A, B, C, D, twisted together, with a far-end of the four wires terminating A and B in a first short circuit, and separately, C and D in a second short circuit; and

attaching a four-wire connector terminating a near end of the four wires.

37. The method for constructing a small set-top unit as set forth in claim 35, further comprising the steps of:

adding circuitry for detecting the first short circuit between the A and B wires, and the second short circuit between the C and D wwires, for when the first short circuitor the second short circuit become an open circuit.

38. The method for constructing a small set-top unit as set forth in claim 35, further comprising the steps of:

adding circuitry for detecting any cuts in the A and B wires, or in the C and D wires.