Security integrated circuit

1. A circuit, comprising:

metal configured memory that stores a first portion of each of a plurality of keys and programmable memory that stores a second portion of each of the plurality of keys, wherein each complete key is separated into metal and programmable portions, the metal portion is fabricated during circuit fabrication, and the programmable portion is programmed in programmable memory of the fabricated circuit; and

an interface to connect to an external authentication system;

wherein the metal configured memory and programmable memory store a prescribed finite number of host keys and matching device keys; and

wherein in response to a received host key from the external authentication system, a matching device key is provided by the circuit.

2. The circuit of claim 1 , wherein the received host key from the external authentication system comprises a challenge and the matching device key provided by the circuit comprises a response to the challenge.

3. The circuit of claim 1 , wherein the external authentication system includes an authentication application that is network connected to an authentication server.

4. The circuit of claim 3 , wherein the authentication application is installed on a device that interfaces with the circuit.

5. The circuit of claim 1 , wherein the received host key from the external authentication system comprises a currently valid host key.

6. The circuit of claim 5 , wherein the currently valid host key changes according to a security policy.

7. The circuit of claim 1 , wherein the interface comprises one or more pads on which one or more electrical probes are placed to connect to the circuit.

8. The circuit of claim 1 , wherein the interface facilitates communication with the circuit via one wire.

9. The circuit of claim 8 , wherein power is provided to the circuit via the one wire.

10. The circuit of claim 1 , wherein the interface facilitates serial communication with the external authentication system.

11. The circuit of claim 1 , wherein the circuit communicates with the external authentication system with a digital signal or a mixed signal.

12. The circuit of claim 1 , wherein no mathematical and/or logical relationships exist between one or more host keys and matching device keys stored in the circuit.

13. The circuit of claim 1 , wherein a mathematical and/or logical relationship exists between an original or first host key and matching device key stored in the circuit.

14. The circuit of claim 1 , wherein the programmable memory further stores a device identifier that identifies a device or a type of device into which the circuit is embedded.

15. The circuit of claim 1 , wherein the programmable memory further stores an encrypted device header.

16. The circuit of claim 1 , wherein metal configured memory comprises read-only memory.

17. The circuit of claim 1 , wherein programmable memory comprises one time programmable non-volatile memory.

18. The circuit of claim 1 , wherein the circuit is included or embedded in an item or product.

19. The circuit of claim 1 , wherein the circuit comprises an integrated circuit.

20. A method, comprising:

configuring metal configured memory of a circuit to store a first portion of each of a plurality of keys and configuring programmable memory of the circuit to store a second portion of each of the plurality of keys, wherein each complete key is separated into metal and programmable portions, the metal portion is fabricated during circuit fabrication, and the programmable portion is programmed in programmable memory of the fabricated circuit; and

configuring an interface of the circuit to connect to an external authentication system;

wherein the metal configured memory and programmable memory store a prescribed finite number of host keys and matching device keys; and

wherein in response to a received host key from the external authentication system, a matching device key is provided by the circuit.