  Weak physical uncloneable function (WPUF) encryption key means that the
manufacturer of the hardware can clone the key but anybody else is unable to so
that. Strong physical uncloneable function (SPUF) encryption key means that
even the manufacturer of the hardware is unable to clone the key. In this
paper, first we introduce a "ultra"-strong PUF with intrinsic dynamical
randomness, which is not only not cloneable but it also gets renewed to an
independent key (with fresh randomness) during each use via the unconditionally
secure key exchange. The solution utilizes the Kirchhoff-law-Johnson-noise
(KLJN) method for dynamical key renewal and a one-time-pad secure key for the
challenge/response process. The secure key is stored in a flash memory on the
chip to provide tamper-resistance and non-volatile storage with zero power
requirements in standby mode. Simplified PUF keys are shown: a strong PUF
utilizing KLJN protocol during the first run and noise-based logic (NBL)
hyperspace vector string verification method for the challenge/response during
the rest of its life or until it is re-initialized. Finally, the simplest PUF
utilizes NBL without KLJN thus it can be cloned by the manufacturer but not by
anybody else.
