Message Signature Validation

[Pivotal Issue 78632442][1]

[1]: https://www.pivotaltracker.com/n/projects/1163646/stories/78632442
![](http://4.bp.blogspot.com/-BKRQ09oH7HI/UhANR7AbsdI/AAAAAAAAF4c/lxLvZQnEtcw/s1600/certifiable.png)