I am using tuf-on-ci and running into issues when the key scheme is ecdsa-sha2-nistp384 (worth noting that these tests aren't failing when using the python tuf client)

I've root caused the issue to the hash algorithm basically hardcoded to use SHA256 here:

It looks like mainly the 256-bit curves are supported here but with a slight change this would also support ECDSA P384.

I've modified this code to the following locally and clear the error using ecdsa-sha2-nistp384 as the key scheme:

// use corresponding hash function for key type
hash := crypto.Hash(0)
if key.Type != KeyTypeEd25519 {
	switch key.Scheme {
	case KeySchemeECDSA_SHA2_P256:
		hash = crypto.SHA256
	case KeySchemeECDSA_SHA2_P384:
		hash = crypto.SHA384
	default:
		hash = crypto.SHA256
	}
}