부산대학교 도서관

This paper presents a physically unclonable function (PUF) using flash time-to-digital converter (TDC) with linearity self-calibration. The proposed PUF utilizes that the variation of delay of delay elements of TDC is unique to the device and unclonable. The proposed PUF is constructed using the flash TDC with linearity self-calibration using histogram method. With the linearity self-calibration operation, variation of delay elements is estimated. The response output of the PUF is calculated using the estimated variation and the challenge inputs. The proposed PUF is a simple digital circuit consisting of basic digital elements. It is easy to design and implement to both SoC and FPGA. It can be used as not only strong PUF but also as a TDC with fine linearity. The experimental results with Artix7 FPGA show that the intra-chip variation is 8.9 % and the inter-chip variation is 46.9 %. The probability of the correct identification is 99.8 %. Extra resources to construct the proposed PUF are 33.7 % of the resources of the TDC with linearity self-calibration.