How do StackExchange sites link user accounts to OpenID accounts?

Question

I like the StackExhchange / StackOverflow approach for integrating OpenID.

As I understand it, the process looks something like this:

• If a user signs up with an OpenID provider (i.e. Google), StackOverflow (or a similar site) creates an account for the user and associates OpenID with this account.
• An existing user can associate multiple OpenID accounts with their StackExchange account.

I would like to imitate this behavior because I did not see it almost convenient for others on other sites.

I know that StackExchange is built on ASP.NET MVC, but I'm not sure if it uses the standard ASP.NET credential model and then adds the OpenID provider to a separate database table or what.

So my questions are:

• How does StackExchange create these accounts? Do they create a user in the standard ASP.NET MVC provider and then bind the identifier or is there a separate process?
• How can StackExchange associate additional OpenID provider accounts with an existing account?

Thanks in advance for any help you can give!

Answer 1

StackExchange sites use the DotNetOpenAuth library (formerly known as the DotNetOpenId library).

User User_OpenID " ". Scot Hanselman