Capacitor based physical unclonable function
AssigneeAnalog Devices International Unlimited Company
InventorJonathan Ephraim David Hurwitz
Life of this patent
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Abstract
The present disclosure relates to a PUF apparatus for generating a persistent, random number. The random number is determined by selecting one or more PUF cells, each of which comprise a matched pair of capacitors that are of identical design, and determining a value that is accurately and reliably indicative of a random manufacturing difference between them, based in which the random number is generated. The random manufacturing differences between the capacitors creates the randomness in the generated random number. Furthermore, because the random manufacturing difference should be relatively stable over time, the generated random number should be persistent.
Claims20
A Physical Unclonable Function, PUF, apparatus comprising:
- a plurality of PUF cells, each PUF cell comprising:
- at least one capacitor divider comprising a first capacitor and a second capacitor sharing a common node;
- and
- a determination unit configured to:
- set a first bias condition across the at least one capacitor divider;
- determine a first nodal measurement that is indicative of a voltage at the common node of the at least one capacitor divider during the first bias condition;
- set a second bias condition across the at least one capacitor divider to change a distribution of charge held by the first capacitor and the second capacitor;
- determine a second nodal measurement that is indicative of a voltage at the common node of the at least one capacitor divider during the second bias condition;
- and
- determine a PUF output based at least in part on a difference between the first measurement and the second measurement.
A method of determining a Physical Unclonable Function, PUF, output using a PUF cell comprising at least one capacitor divider comprising a first capacitor and a second capacitor sharing a common node, the method comprising:
- setting a first bias condition across the at least one capacitor divider;
- determining a first nodal measurement that is indicative of a voltage at the common node of the at least one capacitor divider during the first bias condition;
- setting a second bias condition across the at least one capacitor divider to change a distribution of charge held by the first capacitor and the second capacitor;
- determining a second nodal measurement that is indicative of a voltage at the common node of the at least one capacitor divider during the second bias condition;
- and
- determining the PUF output based at least in part on a difference between the first measurement and the second measurement.
A Physical Unclonable Function, PUF, apparatus comprising:
- a PUF cell comprising:
- at least one capacitor divider comprising a first capacitor and a second capacitor sharing a common node;
- and
- circuitry configured to:
- set a first bias condition across the at least one capacitor divider;
- determine a first nodal measurement that is indicative of a voltage at the common node of the at least one capacitor divider during the first bias condition;
- set a second bias condition across the at least one capacitor divider to change a distribution of charge held by the first capacitor and the second capacitor;
- determine a second nodal measurement that is indicative of a voltage at the common node of the at least one capacitor divider during the second bias condition;
- and
- determine a PUF output based at least in part on a difference between the first measurement and the second measurement.
Dependencies are inferred from the claim text.