Test Pub() and Priv() by exporting the key and signing/verifying from software

[chrisfenner]

This PR enhances the crypto_test.go unit-test by adding a test that creates a TPM key, exports it, and then checks that TPM and software can mutually sign/verify one another.

[chrisfenner]

+CC @AlexandreEXFO in case you have comments on this one.

[AlexandreEXFO]

@chrisfenner : There are errors in the error messages of the TestRoundTrip function since there are RSA and ECC keys. Otherwise, it's good.

By curiosity, do you plan to make a new version soon with the changes? I would like to stop depending on a fork for a project that uses this library.

[chrisfenner]

@chrisfenner : There are errors in the error messages of the TestRoundTrip function since there are RSA and ECC keys. Otherwise, it's good.

By curiosity, do you plan to make a new version soon with the changes? I would like to stop depending on a fork for a project that uses this library.

Thank you! I will kick off another release after this PR goes in.

[chrisfenner]

@chrisfenner : There are errors in the error messages of the TestRoundTrip function since there are RSA and ECC keys. Otherwise, it's good.
By curiosity, do you plan to make a new version soon with the changes? I would like to stop depending on a fork for a project that uses this library.

Thank you! I will kick off another release after this PR goes in.

https://github.com/google/go-tpm/releases/tag/v0.9.3