(How Betrusted Aims to Close the Hardware TOCTOU Gap) While open source is necessary for trustable hardware, it is far from sufficient. This is because “hashing” hardware – verifying its construction down to the transistor level – is typically a destructive process, so trust in hardware is a massive time-of-check/time-of-use (TOCTOU) problem. This talk helps us understand the nature of the TOCTOU problem by providing a brief overview of the supply chain security problem and various classes of hardware implants. We then shift gears to talk about ways to potentially close the TOCTOU gap, concluding with a curated set of verifiable components that we are sharing as an open source mobile communications platform – a kind of combination hardware and software distribution – that we hope can be useful for developing and deploying all manner of open platforms that require a higher level of trust and security.