Is there any way to authenticate users from other web apps using the DNN logins? 

We have a main site that is using DNN and user logins are stored in the asp net membership table. From what I have been reading, the passwords are encrypted using the machine key and then salted. I see where this info is, but can't seem to encrypt passwords correctly using this method. 

The reason for this is we have a lot of websites developed by different chapters of a very large membership organization and they are all using different web technologies (PHP, Coldfusion and .NET) and we'd like to get member's logins to work on those sites as well.

I started with a Coldfusion web application on the same server where our DNN site is, but it doesn't want to work. You'd think it would be strait forward with the Coldfusion encryption function:

Encrypt(passwordstring, key [, algorithm, encoding, IVorSalt, iterations])

I no matter what I try, I never get a matching password value.

Any help, insight or pointing me in the right direction would be greatly appreciated!

I was able to accomplish this via Web Service Exposing the DNN ValidateUser. However, role information you need to expose seperately as i've found out. I am working presently on exposing the Sitemap so that a custom control on the ASP.net web app can read a Node from the DNN tab list, and show appropriate tabs to the user.

If you need more information... im here.