Support for OID 1.3.14.3.2.29 (sha1RSA)

[dpwatrous]

It looks like there is currently no handling of OID 1.3.14.3.2.29 (sha1RSA) , causing the following error to be thrown when computing a digest: "Could not compute certificate digest. Unknown signature OID."

I suspect the same code that handles 1.2.840.113549.1.1.5 would work here, and I'm happy to try to put together a PR for this, but any guidance would be appreciated!

[dpwatrous]

Looking at this issue in python's cryptography library seems to indicate we can treat this the same as 1.2.840.113549.1.1.5 (sha1WithRSAEncryption).

Because the id -> name and name -> id mappings are 1:1, we'd either have to change the structure of the maps or introduce a new name. I'm leaning toward the latter to limit the scope of the change.

[dpwatrous]

A couple more links to similar issues (which include more context):

Chromium: https://codereview.chromium.org/1223763002
Mozilla: https://bugzilla.mozilla.org/show_bug.cgi?id=1042479

[davidlehn]

Fixed in #940.