Improve error messages of Public{Ecc,Rsa}ParametersBuilder

[brandsimon]

I am not sure, if the 'restricted' and 'is_decrypt_key' is wanted, since it is used that way in computing languages (but not in human language).

[brandsimon]

Tbh I am not sure if the logic here is correct.
I am trying to port a shell-script to rust with no success at all. It loads an object into the TPM (protected by a primary-endorsement-key protected by PCRs) and signs something with it.

I'd appreciate if someone can have a look, the shell script, rust-code and output are here:
https://gist.github.com/brandsimon/b6c898a5a5021cf9757756a8319b741e
The public and private portion can be created with this script: (choose PCR 7):
https://gitlab.com/cryptographic_id/cryptographic-id-rs/-/blob/v0.2.2/usr/bin/cryptographic_id_add_initramfs

[ionut-arm]

Hey! Thanks for the patch. Looking at your output and Rust code, it seems you're getting TPM_RC_SCHEME, which (given the documentation of TPM2_Create) would mean you might be using the wrong ECC scheme. For our EK abstraction we use EccScheme::Null - perhaps you can try with that?

[brandsimon]

@ionut-arm
Thank you very much! I think your hint was a huge step into the right direction.

[Superhepper]

There are a lot fo magical things tpm2-tools does in the background that one unfortunately have to do manually when porting from a script into a program. So if one wants to find out the root of the problem one needs to dig through the tpm2-tool code and have the specification ready at hand. But as @ionut-arm mentioned and from my own experience a mismatch in scheme between either a key and operation one tries to perform is not unusual.

[wiktor-k]

I think it looks good 👍 . Fix the spelling though 😅

[brandsimon]

@wiktor-k
I change a typo against a typo 😆

@Superhepper
Thank you, I found a lot in the tpm2-tools (like correct algorithms). I still struggle a bit, but I don't thick it could be related to the logic in PublicEccParametersBuilder anymore. I will ask in the slack channel if I have more questions.