Identification circuit and method for generating an identification bit using physical unclonable functions

A method for generating an identification bit, comprising:

• generating a first output signal from a first circuit which is a function of random parametric variations in said first circuit,
• generating a second output signal from a second circuit which is a function of random parametric variations in said second circuit,
• amplifying said first output and said second output with a third circuit which can be operated in an amplification mode and in a latch mode,
• switch said third circuit in the latch mode to get a digital identification bit.

A device comprising:

• a PUF circuit,
• the PUF circuit comprising at least one switch element,
• the PUF circuit being configured to cause in a first phase an evolution from a predetermined unstable state to a first stable state in which a first signal at a first node and second signal at a second node are substantially constant in time,
• the PUF circuit being further configured to cause after a switching of the at least one switch element an evolution of the PUF circuit in a second phase from the first stable state to a second stable state, wherein the first and second signals are evolving in the second phase to first and second predetermined levels determined by the signal levels at the first stable state.