Free Lunch 2010: Why Public Algorithms Beat the Alternative is an article I just wrote for CSO. The article is online athttp://www.csoonline.com/article/518263/Free_Lunch_2010_Why_Public_Algorithms_Beat_the_Alternative
In it, I explain why vendors should be dropped when they refuse to reveal their crypto algorithms.
Organizations that are serious about information security should never utilize the services of a cryptography firms that refuses to share the inner workings of their crypto algorithms.