Add dummy proof keys and discovery XML

[thomaslevesque]

Fixes #22

Currently there's just a proof-keys.xml file with dummy keys, and a discovery.xml file with the corresponding public keys. In a future evolution, it might be useful to add an option to specify the proof keys file, but then the discover file would need to be updated to match the specified keys.

[tylerbutler]

@thomaslevesque Thanks for the PR! Could you share the cert that you used and the process used to generate it?

[thomaslevesque]

Hi @tylerbutler,

I didn't use a certificate, I just made a new RSACryptoServiceProvider and used ExportCspBlob(true) to get the private key and ExportCspBlob(false) to get the public key.
You can recreate the same keys from the proof-keys.xml file, using ImportCspBlob (which is what the code is doing)

[thomaslevesque]

and ExportCspBlob(false) to get the public key.

Actually, that's not quite right. This only gives the value for the public key in the discovery document. For the exponent and modulus, I used ExportParameters(false) and used the Exponent and Modulus properties of the result.

[thomaslevesque]

If requested, I can add a small program to generate the keys (and maybe rotate them)