PUF

A PUF exploits tiny, uncontrollable manufacturing variations in a chip to produce a unique fingerprint that cannot be copied, even by the original manufacturer. When challenged with an input, the circuit produces a device-specific response that can serve as a hardware root of trust, a key generator, or an anti-counterfeiting mechanism. Because the secret is derived from physical structure rather than stored in memory, it is much harder to extract than a conventional key.