Challenge-response generation using RO-PUF with reduced hardware

Cryptography looks forward to generate secrete key from integrated circuit. A silicon based device having uncontrollable feature in term of measurable output can turned into physically unclonable function (PUF). Multiplexer based PUF works on unpredictable delay difference between two parallel paths, while Ring oscillator based PUF works on frequency deviation generated due to random variation of CMOS fabrication process. Hardware based intrinsic features must include to generate a random response which fuzzified to generate a reliable secret key. Our design incorporates PUF based on circuit variation instead of process variation, PISO shift register reduce the hardware compared to existing RO-OUF. A 4-bit challenge generates 16-bit random response with measured reliability in term of intra hamming distance approx to mid value.