I looked into using SecureString at one point for a project that I’m working on, but didn’t find it very useful unfortunately. There’s cases like the SMO Server instantiation where it accepts it, but when establishing a regular ADO.NET connection, there’s no support for it, so then you have to pull out the clear-text password out of the SecureString and make it part of the connection string (bypassing the security benefits of it). Also, it’s easy to get a string into the SecureString, but not as easy to get the clear-text value out.
Here’s some info on that:
http://cs.rthand.com/blogs/blog_with_righthand/archive/2005/06/10/40.aspx
http://bartdesmet.net/blogs/bart/archive/2006/03/31/3851.aspx
The second guy makes a good point, that if you use the SecureString, you should only store the clear-text string for as little time as possible, and then nulling it out…but then that brings up some other issues. Also, there’s the issue of where the string resides between the time that the user enters it and the time we get it into the SecureString…we’d need to capture each character as it’s entered and append it to the securestring, to truly make it secure.
I wish they would’ve made it much more usable, as I think it’s a great direction to go towards, but right now just SMO and some of the Cryptography classes are the only ones that support it.
Here’s a control that could come in handy if you really need to use it: SecurePasswordTextBox – A textbox that uses the SecureString class (http://weblogs.asp.net/pglavich/archive/2006/02/26/439077.aspx)