Abstract: Physical unclonable function (PUF) is a new type of hardware security primitive. It
prevents chips from over-manufacturing and illegally copying and can be implemented with ASICs
and FPGAs. PUF can be used for secure secret key generation and chips authentication. Strong PUF
is an important category of PUF and it has a great CRP space for safety authentication of device
identity. As a classic strong PUF design, arbiter PUF is expensive in hardware overhead and less ideal
in uniqueness, which makes it not suitable for some resource-intensive applications like embedded
systems and IoT devices. To decrease the hardware overhead, a new lightweight strong PUF design
has been proposed. A linear feedback shift register is used as obfuscating logic of a weak PUF to
obtain lots of responses. With simple structure, this design is easy to implement. The PUF design is
implemented and evaluated on a 28 nm FPGA developing board. The experimental results show that
the randomness of the PUF is 49.8%, the uniqueness is 50.25%, and the hardware overhead is very
small.

Key words: hardware security, physical unclonable function, linear feedback shift register, FPGA;
lightweight