What Encryption Algorithm does the .Net Membership use?

Question

What algorithem .net membership uses to encrypt username and password, actually i used membership in my web application and mean while i created a desktop application and want to use it with my database in which .Net Membership is used and username and password is encrypted... i want to make it sure the users that have credentials in web application will use this desktop application... but the issue is which algorithm should i use to verify the user credential...? surely it will require some encryption as the users credential data is encrypted by membership. 

Thank you in advance :)