With the development of technology

information security has been greatly challenged. The Physical Unclonable Function (PUF) circuit is a new type of key generation circuit. Resistive Random Access Memory (RRAM) can provide a source of physical random entropy

which makes the PUF physically impossible be attacked. However

in the RRAM-based PUF design

the RRAM delay unit’s test response pair (Challenge Response Pair

CRP) efficiency is not high enough. In this paper

a PUF structure based on RRAM delay unit is proposed. The delay unit outputs the resistance of the RRAM to the inverter to form a delay of the pulse. Finally

the determiner determines that the two pulses are in sequence and is coded as "0" and "1"

this is the output bit of the PUF. Based on the RRAM delay unit

this paper designs 8-bit

16-bit

32-bit

64-bit PUF. These PUFs greatly improve the efficiency of PUF RRAM cells under the premise of ensuring good randomness

stability and uniqueness. The experimental results show that the design can effectively improve the efficiency of RRAM

so that PUF can prevent external attacks better.