Specialized circuitry for cryptographic authentication and other purposes

• US 20060184807A1
• Filed: 03/23/2006
• Published: 08/17/2006
• Est. Priority Date: 09/02/1999
• Status: Active Grant

• Current Assignee: Benjamin C. Jun, Joshua M. Jaffe, Paul C. Kocher
• Original Assignee: Benjamin C. Jun, Joshua M. Jaffe, Paul C. Kocher
• Inventors: Kocher, Paul C., Jun, Benjamin C., Jaffe, Joshua M.
• Granted Patent: US 9,569,628 B2
• Time in Patent Office: Days
• US Class Current: 713/194
• CPC Class Codes: G06F 21/107 License processing; Key processing
• CPC Class Codes: G06F 21/602 Providing cryptographic facilities or services
• CPC Class Codes: G06F 21/72 in cryptographic circuits
• CPC Class Codes: G06F 2211/007 Encryption, En-/decode, En-/decipher, En-/decypher, Scramble, (De-)compress
• CPC Class Codes: G06F 2221/2101 Auditing as a secondary aspect
• CPC Class Codes: G06Q 20/367 involving electronic purses or money safes
• CPC Class Codes: H04L 2209/127 Trusted platform modules [TPM]
• CPC Class Codes: H04L 2209/603 Digital right managament [DRM]
• CPC Class Codes: H04L 9/0833 involving conference or group key network architectures or network communication protocols for key management in group communication in a packet data network H04L63/065

Abstract

To prevent piracy, audiovisual content is encrypted prior to transmission to consumers. A low-cost, high-security cryptographic rights module (such as a smartcard) enables devices such as players/displays to decode such content. Security-critical functions may be performed by the cryptographic module in a manner that allows security compromises to be addressed by upgrading or replacing cryptographic modules, thereby avoiding the need to replace or modify other (typically much higher-cost) components. The security module contains cryptographic keys, which it uses to process rights enablement messages (REMs) and key derivation messages (KDMs). From a REM and KDM, the security module derives key data corresponding to content, uses public key and/or symmetric cryptography to re-encrypt the derived key data for another device, and provides the re-encrypted key data to the decoding device. The decoding device then uses cryptographic values derived from the re-encrypted key data to decrypt the content.

Claims

1. A circuit configured to cryptographically authenticate itself, comprising:

(a) a plurality of logic cells selected from a set of supported logic cells;

(b) a plurality of conductive elements interconnecting said logic cells with each other and with other circuit elements, where said interconnections are selected using a random number source, and where said interconnection selection is configured to comply with

(i) wiring limitations, and

(ii) circuit area constraints;

(c) logic configured to receive inputs to said circuit, use said interconnected logic cells to cryptographically transform said inputs into result values usable by an external device to authenticate said circuit, and output said result values.

2. The circuit of claim 1 further comprising:

(i) nonvolatile memory;

(ii) additional logic for storing information in said nonvolatile memory pertaining to operations performed by said circuit; and

(iii) additional logic for retrieving information from said nonvolatile memory and incorporating said retrieved information in said cryptographic transformations performed by said circuit.

3. The circuit of claim 2 where said incorporated information includes a key.

4. The circuit of claim 1 where said interconnected logic cells and said logic in (c) are configured to frustrate attempts to compute said inputs from said outputs by adversaries who do not know the configuration of said interconnected logic cells.

5. The circuit of claim 1 where the said random number source is a pseudorandom number generator.

6. The circuit of claim 1 incorporated in a conditional access module for regulating access to audiovisual content.

7. The circuit of claim 1 incorporated in an electronic transit pass.

8. The circuit of claim 1 incorporated in an authentication token.

9. The circuit of claim 1 where said transformation is pseudoasymmetric.

10. The circuit of claim 9 where said transformation is a block cipher operation.

11. The circuit of claim 1 where said transformation is a block cipher operation.

12. A method for generating a cryptographic circuit, comprising:

(a) selecting a plurality of logic cells from a set of logic cells;

(b) using a random number source to define conductive elements interconnecting said logic cells with each other and with other circuit elements, where said interconnections are selected using a random number source, and where said interconnection selection is configured to comply with

(i) wiring limitations, and

(ii) circuit area constraints;

(c) combining said interconnected logic cells with logic configured to receive inputs to said circuit, use said interconnected logic cells in cryptographically transforming said inputs into result values, and output said result values.

13. The method of claim 12 where said cryptographically transforming includes a block cipher operation incorporating said interconnected logic cells.

14. The method of claim 12 where said logic in (c) includes logic for:

(i) storing information pertaining to operations performed by said circuit in a nonvolatile memory;

(ii) retrieving information from said nonvolatile memory; and

(iii) incorporating said retrieved information in said cryptographic transformations performed by said circuit.

15. The method of claim 14 where said cryptographically transforming includes a block cipher operation incorporating said interconnected logic cells and keyed with a key retrieved from said nonvolatile memory.