Raul Garcia's blog

I am including a link to Laurentiu Cristofor's blog: http://blogs.msdn.com/lcris . Laurentiu is one of the most valuable contributors in the SQL Security forums, and his articles and demos are great resources for anyone interested in SQL Server security...

Digital signatures in SQL Server 2005 modules can be used to extend the privileges of the caller for the duration of the call. This feature enables the ability to create an application that can enable authorized callers to access resources (such as tables, symmetric keys, etc.) that otherwise would require highly escalated privileges. While adding a signature when you have control of the certificate’s private key is really straightforward, but it may not be so obvious how to distribute an application that uses this feature without giving away the private key. ...