Feature request: support for `TPM_ECC_CURVE_25519`

[wiktor-k]

Hello,

I've noticed that Trusted Platform Module 2.0: Library Part 2: Structures has been extended with EdDSA signing algorithms: TPM_ECC_CURVE_25519 0x0040 curve to support EdDSA (table 9, p. 46).

While I don't see it in the wild I think it'd be a good idea to include in swtpm.

Thanks for your time!

[stefanberger]

While I don't see it in the wild I think it'd be a good idea to include in swtpm.

Maybe... swtpm support alone isn't enough but you need to also convince IBM and Intel TSS2 folks to support it -- I would need their support for being able to test it.

[wiktor-k]

Maybe... swtpm support alone isn't enough but you need to also convince IBM and Intel TSS2 folks to support it -- I would need their support for being able to test it.

Yes, excellent idea. I've created a parallel ticket at tpm2-software/tpm2-tss#3074

[stefanberger]

I have looked at this a bit now, including writing some code. EdDSA is presumably ED448 and ED25519 as implemented by OpenSSL (https://docs.openssl.org/3.4/man7/EVP_SIGNATURE-ED25519/ ). However, TCG added Curve25519 and Curve448 to their registry ( https://trustedcomputinggroup.org/wp-content/uploads/TCG-Algorithm-Registry-Version-2.0_pub.pdf ). These are not the same from what I can see and I am wondering whether the curves in the registry should be ignored...