System and method for cryptographic key identification

Patent metadata

Field	Value
Publication number	US-9667419-B2
Application number	US-201514593452-A
Country	US
Kind code	B2
Filing date	Jan 9, 2015
Priority date	Jan 10, 2014
Publication date	May 30, 2017
Grant date	May 30, 2017

Abstract

A method for determining a cryptographic key for a MEMS device includes identifying physical properties for the device. A feature vector having a plurality of values is determined. Each of the values correspond to different physical properties. The cryptographic key is determined from the feature vector. The cryptographic key can be determined using a fuzzy extractor. The cryptographic key can be determined using different feature vectors corresponding to different channels in a device or different MEMS structures in the device.

First claim

What is claimed is:

1. A method for deriving a cryptographic key for a microelectromechanical sensor (MEMS) device, comprising:
determining a first feature vector for a first MEMS device, the first feature vector having a first plurality of values, each of the values in the first plurality corresponding to a first measurement, respectively, of a plurality of different physical properties of the first MEMS device;
determining a second feature vector having a second plurality of values, each of the values in the second plurality corresponding to a second measurement, respectively, of the plurality of different physical properties of the first MEMS device or to a first measurement, respectively, of the plurality of different physical properties of a second MEMS device; and
deriving the cryptographic key from the first feature vector and the second feature vector using a processor.

2. The method of claim 1 , wherein the plurality of different physical properties of the device comprises a plurality selected from the following: a resonant frequency, a stiffness of a spring constant with reference to the resonant frequency, a raw offset of the device, a capacitance in the device, a release voltage, a difference in two or more snap voltages, an attenuation value of movement of the device, a resistance in the device, an inductance, a movement curve, an inherent circuit interference, a spectrum pattern, and a voltage applied to a test signal.

3. The method of claim 2 , further comprising:
obtaining the capacitance by displacing the device.

4. The method of claim 1 , wherein the derivation of the cryptographic key further comprises:
providing the first feature vector and the second feature vector to a fuzzy extractor; and
deriving the cryptographic key using the fuzzy extractor.

5. The method of claim 4 , further comprising:
identifying the cryptographic key based on a pair-wise comparison of the first feature vector and the second feature vector.

6. The method of claim 4 , further comprising:
storing data from the fuzzy extractor in a non-volatile memory.

7. The method of claim 1 , wherein the derivation of the cryptographic key further comprises:
performing a comparison of the first feature vector and the second feature vector to generate a single bit;
performing an error correction computation of the single bit; and
deriving the cryptographic key based on the single bit.

8. The method of claim 7 , wherein the comparison is a pair-wise comparison of the first feature vector and the second feature vector.

Assignees

• Bosch Gmbh Robert

Inventors

• Guajardo Merchan Jorge
• Stahl Heiko
• Lewis Matthew
• Mueller Andreas
• Schellin Ralf

Classifications

• H04L9/0866 Primary

  involving user or device identifiers, e.g. serial number, physical or biometrical information, DNA, hand-signature or measurable physical characteristics · CPC title

• G06F21/73

  by creating or determining hardware identification, e.g. serial numbers · CPC title