feature request: expose HMAC functionality in the hash module

[nchieng]

Would it be possible to add HMAC functionality in the hash module, so we can calculate hashed signatures when a key/secret is provided.

[rgkimball]

Was just looking for the same functionality. This is essential for signing requests when using OAuth 1.0; more details are available in the official documentation here: oauth.net/core/1.0a

See also: RFC 2104