This module implements the OAuth 1.0 standard for use with Drupal and acts as a support module for other modules that wish to use OAuth.
Drupal 6 and 7
This module includes a slightly modified version of this OAuth Client/Server library.
The module implements server side authentication. If you just need to sign requests with a set of OAuth Credentials, then install the module Guzzle OAuth.
Two legged authentication has been implemented using the OAuth PECL extension. Three-legged authentication is on the way.