PUF circuits utilize multiple identical bit-cells to generate their unique keys. Thus, the Si area of each bit has a profound impact on the circuit. A method for extraction of multiple independent bits from single PUF cells is proposed. This method utilizes PUF preselection 'tilt' tests to obtain a new, uncorrelated, entropy source. During tilt tests, intentional controllable mismatch is introduced to the PUF cells, and their stability is concluded. The test could be revisited as a method to measure the internal mismatch size, by finding the tilt size required to flip the test result from 'pass' to 'fail'. As the mismatch size is random and uncorrelated, it could be used to extract multiple additional PUF bits, as well as to find the unstable bit-cells relative to each new PUF bit. A Si implementation, which relies on the capacitive tilt PUF, in TSMC 65nm, is presented, with two additional bits. This demonstrates the applicability of the scheme for multiple new bits. Measured results of the second new bit show BER of 4E-4, zero additional cell area and excellent uniqueness and randomness.
|Title of host publication||IEEE International Symposium on Circuits and Systems, ISCAS 2022|
|Publisher||Institute of Electrical and Electronics Engineers Inc.|
|Number of pages||5|
|State||Published - 2022|
|Event||2022 IEEE International Symposium on Circuits and Systems, ISCAS 2022 - Austin, United States|
Duration: 27 May 2022 → 1 Jun 2022
|Name||Proceedings - IEEE International Symposium on Circuits and Systems|
|Conference||2022 IEEE International Symposium on Circuits and Systems, ISCAS 2022|
|Period||27/05/22 → 1/06/22|
Bibliographical noteFunding Information:
This work was supported in part by the Israel Innovation Authority.
© 2022 IEEE.
- Mirror PUF
- tilt test