IDENTIFICATION OF INTEGRATED CIRCUITS

• US 20100287604A1
• Filed: 05/11/2009
• Published: 11/11/2010
• Est. Priority Date: 05/11/2009
• Status: Active Grant

• Current Assignee: Empire Technology Development LLC (Allied Inventors Management, LLC), Regents of the University of California (University of California)
• Original Assignee: Technology Currents LLC (Intellectual Ventures LLC)
• Inventors: Koushanfar, Farinaz, Potkonjak, Miodrag
• Granted Patent: US 8,417,754 B2
• Time in Patent Office: Days
• US Class Current: 726/6
• CPC Class Codes: G01R 19/25 using digital measurement techniques
• CPC Class Codes: G01R 31/2851 Testing of integrated circuits [IC] G01R31/317 takes precedence; testing individual devices G01R31/26; testing printed circuits G01R31/2801
• CPC Class Codes: G06F 15/00 Digital computers in general details G06F1/00 – G06F13/00; Data processing equipment in general
• CPC Class Codes: G06F 21/73 by creating or determining hardware identification, e.g. serial numbers

Abstract

Techniques are generally described for generating an identification number for an integrated circuit (IC). In some examples, methods for generating an identification of an IC may comprise selecting circuit elements of the IC, evaluating measurements of an attribute of the IC for the selected circuit elements, wherein individual measurements are associated with corresponding input vectors previously applied to the IC, solving a plurality of equations formulated based at least in part on the measurements taken of the attribute of the IC for the selected circuit elements to determine scaling factors for the selected circuit elements, and transforming the determined scaling factors for the selected circuit elements to generate an identification number of the IC. Additional variants and embodiments may also be disclosed.

Claims

1. A method for a computing device to generate an identification number of an integrated circuit (IC) including circuit elements, the method comprising:

selecting circuit elements of the IC;

evaluating measurements of an attribute of the IC for the selected circuit elements, wherein individual measurements are associated with corresponding input vectors previously applied to the IC;

solving a plurality of equations formulated based at least in part on the measurements taken of the attribute of the IC for the selected circuit elements to determine scaling factors for the selected circuit elements; and

transforming the determined scaling factors for the selected circuit elements to generate an identification number of the IC.

2. The method of claim 1, wherein solving the plurality of equation comprises solving the plurality of equations formulated further based on additional measurements of another attribute of the IC for the selected circuit elements.

3. The method of claim 2, wherein the attribute and the another attribute include two of a leakage current, a delay, a switching power, a parasitic capacitance, an inductance, a resistance, a gain, an offset voltage, a threshold voltage, an operating temperature, a power consumption, or an idle current.

4. The method of claim 1, wherein solving the plurality of equation comprises solving the plurality of equations further including a corresponding error term based at least in part on an error in the measurements.

5. The method of claim 4, wherein solving the plurality of equations further comprises:

formulating an optimization problem that includes an objective function that reduces a norm of the error terms of the plurality of equations.

6. The method of claim 1, wherein transforming the determined scaling factors further comprises:

selecting one or more of the scaling factors;

mapping the one or more selected scaling factors into corresponding binary codes; and

generating the identification number of the IC using the mapped binary codes for the selected scaling factors.

7. The method of claim 1, wherein transforming comprises:

generating a probability distribution function (PDF) of the scaling factors;

partitioning an area under the PDF into individual segments such that each of the individual segments have approximately equal area;

assigning binary codes to the individual segments such that each individual segment is associated with a respective one of the binary codes;

assigning binary codes to the individual scaling factors included in the individual segments based on the binary codes assigned to the individual segments; and

generating the identification number of the IC using the binary codes assigned to the individual scaling factors.

8. The method of claim 1, the method further comprising:

evaluating a collision probability of the generated identification.

9. The method of claim 8, wherein selecting the circuit elements further comprises selecting a first plurality of circuit elements, and wherein the generated identification number is a first identification number, the method further comprising:

determining that the collision probability is higher than a threshold collision probability;

selecting a second plurality of circuit elements based on determining that the collision probability is higher, wherein the second plurality of circuit elements includes more circuit elements compared to the first plurality of circuit elements; and

generating a second identification number of the IC, such that the second identification number has a relatively lower collision probability than the first identification number.

10. A method for a computing device to generate an identification number of an integrated circuit (IC) including circuit elements, the method comprising:

initiating an application of input vectors to one or more of the circuit elements included in the IC;

receiving measurement values responsive to the application of input vectors, wherein the measurement values correspond to values measured for one or more attributes of the one or more circuit elements in response to the application of input vectors;

formulating a plurality of equations based on the corresponding measured values, wherein each of the plurality of equations includes one or more scaling factors of the corresponding one or more circuit elements;

solving the plurality of equations to determine the one or more scaling factors of the corresponding one or more circuit elements; and

transforming the determined one or more scaling factors to generate the identification number of the IC.

11. The method of claim 10, wherein each of the one or more attributes include one of a leakage current, a delay, a switching power, a parasitic capacitance, an inductance, a resistance, a gain, an offset voltage, a threshold voltage, an operating temperature, a power consumption, or an idle current.

12. The method of claim 10, wherein solving the plurality of equations comprises solving equations that include one or more terms corresponding to one or more circuit elements, and wherein each of the one or more terms includes a nominal value of an attribute of the corresponding circuit element and a scaling factor of the corresponding circuit element.

13. The method of claim 10, wherein solving the plurality of equations comprise solving equations that further include a corresponding error term based at least in part on an error in a corresponding measurement value.

14. The method of claim 13, further comprising:

formulating an optimization problem that includes an objective function that reduces a norm of the error terms of individual equations.

15. The method of claim 13, further comprising:

solving the optimization problem using one of linear programming, piecewise linear programming, non-linear programming, quadratic programming, or convex programming.

16. The method of claim 10, further comprising identifying one or more of the circuit elements as ambiguous circuit elements, wherein formulating the plurality of equations further comprises formulating the plurality of equations such that the one or more of the ambiguous circuit elements are excluded from individual equations of the plurality of equations.

17. The method of claim 10, further comprising:

causing a change in an operating condition of the IC to reduce the precision required for the measurement values.

18. The method of claim 10, wherein transforming the determined one or more scaling factors further comprises:

selecting one or more of the scaling factors;

mapping the one or more selected scaling factors into corresponding binary codes; and

generating the identification number of the IC using the binary codes.

19. The method of claim 18, further comprising:

identifying one or more bits of an indicator string corresponding to one or more circuit elements whose scaling factors have been selected; and

setting the identified one or more bits to 1, such that the indicator string indicates the circuit elements whose scaling factors have been used for generation of the identification number of the IC.

20. The method of claim 18, wherein selecting one or more of the scaling factors further comprises:

generating a probability distribution function (PDF) of the scaling factors;

partitioning an area under the PDF into individual segments;

dividing the individual segments into a first set of segments and a second set of segments, such that the individual segments in the first set of segments and the individual segments in the second set of segments are interleaved; and

selecting one or more scaling factors that are in the first set of segments.

21. The method of claim 20, wherein mapping comprises:

assigning binary codes to the individual segments in the first set of segments such that each individual segment in the first set of segments is associated with a respective one of the binary codes; and

assigning binary codes to the scaling factors included in the individual segments of the first set of segments based on the binary codes assigned to the individual segments.

22. The method of claim 10, wherein transforming the determined one or more scaling factors further comprises:

generating a probability distribution function (PDF) of the scaling factors;

partitioning an area under the PDF into individual segments, each segment having approximately equal area;

assigning binary codes to the individual segments such that each individual segment is associated with a respective one of the binary codes;

assigning binary codes to the scaling factors included in the individual segments based on the binary codes assigned to the individual segments; and

generating the identification number of the IC using the binary codes assigned to the scaling factors.

23. The method of claim 10, further comprising:

authenticating the IC, in response to determining the one or more scaling factors and/or generating the identification number of the IC.

24. The method from claim 23, wherein authenticating the IC further comprises:

challenging an identification of the IC by initiating an application of one or more input vectors to one or more of the circuit elements included in the IC;

receiving response values responsive to the challenging, wherein the response values include indication of one or more operational characteristics of the one or more circuit elements;

comparing the received response values with response values stored in a database external to the IC; and

authenticating the IC based at least in part on said comparing.

25. The method from claim 23, further comprising:

granting the IC or a user of the IC access or operational rights to one or more services or devices, based at least in part on authenticating the IC.

26. The method from claim 10, further comprising:

determining a schedule of data assignment to one or more circuit elements of the IC, such that a total leakage current, temperature, parasitic capacitance or speed of aging of the IC is reduced.

27. The method from claim 10, further comprising:

determining an operational voltage of the IC for a task to be executed on the IC within a duration of time such that a total leakage current, temperature, parasitic capacitance or speed of aging of the IC is reduced, based at least in part on the determined scaling factors of one or more circuit elements.

28. An apparatus arranged to determine an identification number of an integrated circuit (IC) including circuit elements, the apparatus comprising:

a storage medium configured to store programming instructions; and

a processor coupled to the storage medium and configured by the programming instructions to cause the apparatus, when the programming instructions are executed by the processor, to;

initiate an application of input vectors to one or more of the circuit elements included in the IC;

receive measurement values responsive to the application of input vectors, wherein the measurement values correspond to values measured for one or more attributes of the one or more circuit elements in response to the application of input vectors;

formulate a plurality of equations based on the corresponding measured values, wherein each of the plurality of equations includes one or more scaling factors of the corresponding one or more circuit elements;

solve the plurality of equations to determine the one or more scaling factors of the corresponding one or more circuit elements; and

transform the determined one or more scaling factors to generate the identification number of the IC.

29. The apparatus of claim 28, wherein the processor is further configured by the programming instructions to cause the apparatus to transform the determined one or more scaling factors by causing the apparatus to:

select one or more of the scaling factors;

map the one or more selected scaling factors into corresponding binary codes; and

generate the identification number of the IC using the binary codes.