Memory's job is to store bits reliably, but the same chip carries an accidental gift: no two memory arrays are physically identical, because manufacturing imposes random microscopic variation. A physical unclonable function (PUF) harvests that randomness into a unique device fingerprint. Micron's 2022 grant does this with NAND.
The grant US11469909B2 (issued October 11, 2022; Micron Technology, Inc.; CPC H04L 9/3278 PUF-based authentication, G06F 21/72 cryptographic-hardware security, G11C 16/0483 NAND array) claims a physical unclonable function implemented with a NAND memory array. The H04L 9/3278 code is the PUF-authentication classification - this is explicitly a security primitive.
Why is this hard to clone? The fingerprint comes from analog physics - threshold voltages and timing quirks unique to each die - not from a value written into memory. An attacker cannot read out and copy a secret that was never stored as a value; it is emergent from the silicon, which is what makes a PUF attractive as a root of trust.
Using NAND specifically is clever resource reuse. The device already has a large NAND array; deriving a PUF from it avoids adding dedicated security hardware. The memory does double duty - storage and identity - which is exactly the kind of efficiency a cost-pressured memory vendor like Micron values.
This is a different face of memory IP than bandwidth or capacity. The patent record shows memory makers claiming territory in security primitives, because as memory ends up in everything from datacenters to edge devices, a built-in hardware identity becomes a sellable feature.
For the reader, the point is that a memory chip can be a security component. Micron's 2022 NAND-PUF grant turns manufacturing variation - usually a defect to be minimized - into a feature: a fingerprint that authenticates the device itself.