Implement RSA encrypt/decrypt and sign/verify

[qmuntal]

Please review #5 first.

This PR implements the following RSA algorithms:

• 17459e4: private and public key generation
• 90e2201: encryption and decryption without padding and with OAEP or PKCS1 paddings
• 70eb2ec: sign and verify with PCKS1v15 padding
• e2bd3b2: sign and verify with PSS padding

The Microsoft Windows Cryptographic Primitives Library Security Policy Document says that exporting the private components of RSA keys is not allowed in FIPS mode:

Exporting the RSA private key by supplying a blob type of BCRYPT_PRIVATE_KEY_BLOB, BCRYPT_RSAFULLPRIVATE_BLOB, or BCRYPT_RSAPRIVATE_BLOB to BCryptExportKey() is not allowed in FIPS mode.

I haven't found any other way to implement GenerateKeyRSA, so at the moment I will use the BCRYPT_RSAFULLPRIVATE_BLOB type and once all the bindings are done we can talk with the CNG team for support on all the pieces that are missing, listed in #4. On the other hand, .NET runtime uses it.

[qmuntal]

@dagood please review 402be0e, which was been committed after you approved the PR.

[dagood]

LGTM, just a suggestion on a comment. 😄

[jaredpar]

On the other hand, .NET runtime uses it.

We should just sync up with .NET runtime and see if they already went down this discussion path with CNG. Maybe they have the reply handy still.

[jaredpar]

Made it about halfway through commits. Will pick up the rest tonight / tomorrow morning.

[qmuntal]

We should just sync up with .NET runtime and see if they already went down this discussion path with CNG. Maybe they have the reply handy still.

@jaredpar good point, who should I contact?