onelogin/ruby-saml — pull request #37 by lawrencepit (2012-05-06 10:39:21+00:00)
Title:  Optionally allow for clock drifts

Even when both IdP and SP systems sync their clocks against the same sources using NTP, issues occur with the NotBefore condition because the IdP may drift slightly ahead of the SP. The SP side should be able to account for small clock drifts that occur naturally.

See also https://github.com/onelogin/ruby-saml/issues/17