ECDSA Support on Windows

[spilikin]

Hi,

do you have any plans to support ECDSA EK/AK on Windows?

Currently the windows implementation seem to ignore the KeyConfig altogether:

https://github.com/google/go-attestation/blob/master/attest/tpm_windows.go#L289-L314

P.S. RSA works like a Charm

[hslatman]

@spilikin I believe AKs can only be RSA on Windows. There's some changes to the implementation logic you linked above in the PR here #343 that mention it in a comment. It builds on changes from #274.

[spilikin]

@hslatman thanks for reply. I will give this branch a try, it seems to implement the App-Keys (TPM.NewKey) on Windows as well.

[hslatman]

@spilikin yes, it does 🙂

Note that there's more Windows things in #317. #343 was created to upstream the changes in smaller batches for easier review.

If you want to have all of the Windows support we've worked on, you could try checking out the surrogate branch from https://github.com/smallstep/go-attestation/tree/surrogate. That's the fork with renamed Go module that we're currently using. It's not fully up-to-date with changes from this repo, though.