Non-volatile memory with physical unclonable function
In accordance with a first aspect of the present disclosure, a non-volatile memory is provided, comprising: a plurality of storage elements; a plurality of access transistors, said access transistors being connected to one or more of said storage elements; a measurement unit, wherein said measurement unit is configured to measure a variation between electrical characteristics of said access transistors; a processing unit configured to use said variation between electric characteristics as a physical unclonable function. In accordance with a second aspect of the present disclosure, a corresponding method of manufacturing a non-volatile memory is conceived.
1. A non-volatile memory, comprising:
a plurality of storage elements;
a plurality of access transistors, said access transistors being connected to one or more of said storage elements;
a measurement unit, wherein said measurement unit is configured to measure a variation between electrical characteristics of said access transistors;
a processing unit configured to use said variation between electric characteristics as a physical unclonable function.
2. The memory of claim 1 , wherein the measurement unit is configured to measure the variation between electrical characteristics by comparing currents through access transistors with the same gate voltage.
3. The memory of claim 1 , wherein the measurement unit is configured to measure the variation between electrical characteristics by connecting gate voltages of the access transistors to drain voltages of the access transistors and forcing a predefined current through the access transistors.
4. The memory of claim 1 , wherein the measurement unit is configured to measure the variation between electrical characteristics by comparing, between access transistors, voltages for conducting a predefined current.
5. The memory of claim 1 , wherein the electric characteristics are the threshold voltages of the access transistors.
6. The memory of claim 1 , wherein the measurement unit is configured to measure a variation between electrical characteristics of a subset of said access transistors.
7. The memory of claim 6 , wherein said subset is defined in read-only memory, ROM, code.
8. The memory of claim 1 , wherein the access transistors are N-type metal-oxide-semiconductor, NMOS, transistors.
9. The memory of claim 1 , wherein the processing unit is further configured to apply redundancy to the measured variation between electrical characteristics.
10. The memory of claim 9 , wherein applying said redundancy comprises applying an error correction scheme to the measured variation between electrical characteristics.
11. The memory of claim 1 , wherein the processing unit is further configured to generate an encryption key based on the physical unclonable function.
12. The memory of claim 1 , wherein each access transistor is connected in series with one or more of said storage elements.
13. The memory of claim 1 , being a flash memory.
14. A security device comprising the memory of claim 1 .
15. A method of manufacturing a non-volatile memory, comprising:
providing the non-volatile memory with a plurality of storage elements;
providing the non-volatile memory with a plurality of access transistors, said access transistors being connected to one or more of said storage elements;
providing the non-volatile memory with a measurement unit, wherein said measurement unit is configured to measure a variation between electrical characteristics of said access transistors;
providing the non-volatile memory with a processing unit, wherein the processing unit is configured to use said variation between electrical characteristics as a physical unclonable function.