ms-tpm-20-ref

Hopefully 2025 will be the year of open-source silicon + open firmware RoT! https://opensource.googleblog.com/2025/02/fabrication-begins... For client devices, https://lowrisc.org/news/lowrisc-a-decade-of-bringing-open-s... > OpenTitan’s “Earl Grey”, will be the plan of record hardware RoT for [2025] Chromebooks.. Caliptra, another open source Root of Trust project with wide industry adoption, has incorporated a considerable amount of OpenTitan’s IP into its design.. OpenTitan’s CPU core, the Ibex RISC-V microcontroller, is an important project in its own right.. Microsoft based its CHERIoT-Ibex design on lowRISC’s commercial-grade Ibex CPU core, extending it with the proven CHERI hardware security extensions. For servers, https://github.com/chipsalliance/Caliptra & https://146a55aca6f00848c565-a7635525d40ac1c70300198708936b4... > Caliptr

TPM is one possible use case for OpenTitan, https://opentitan.org/book/doc/use_cases/index.html OpenTitan’s mission is to raise the security bar industry-wide by implementing a transparent, logically secure hardware root of trust with wide application.. from data center integrations, to embedded security applications such as security keys and smart cards.. OpenTitan can be used to implement the full Trusted Platform Module (TPM) 2.0 specification to meet client and server platform use cases. TPM reference code is open-source, https://github.com/Microsoft/ms-tpm-20-ref

One reasonable way to do this could involve running the reference TPM2 simulator [0] on the Arduino. It's just a C library that already implements all the cryptographic routines and TPM2 commands. In fact, this is basically how TPM vendors implement their chips. They just generally have: - A lot more hardening against physical attacks - Cryptographic libraries optimized for their low-resource hardware - (sometimes) a vendor certificate for a primary TPM key, aka an "EK cert" Certainly a TPM running on an Arduino wouldn't have the physical hardware properties of a "real" TPM. But you could probably get it into a state with similar software properties. [0] https://github.com/microsoft/ms-tpm-20-ref

It depends on how the TPM is being used by the OS and its apps. If it’s purely being used for the crypto key storage and crypto operations, then you can probably use something like the MS reference implementation [0]. If the OS requires attestation and endorsement, there is a manufacturer key pair that is embedded into the chip that you can use to attest and verify that the TPM you are interacting with is indeed from a particular manufacturer. That aspect would not be doable for an emulated DIY TPM. [0] https://github.com/microsoft/ms-tpm-20-ref

If you look at IBM's TPM 2.0 implementation[1], you can see that they don't use any well tested libraries for crypto primitives, but rather uses what looks like home-cooked crypto implementation. Microsoft, on the other hand, seems to support OpenSSL and wolfSSL in their simulator[2]. [1] - http://ibmswtpm.sourceforge.net/ibmswtpm2.html [2] - https://github.com/microsoft/ms-tpm-20-ref