Where is a good description of User Login values in SharePoint 2010 with and without claims?

Question

If I look at HttpContext.Current.User.Identity.Name I get values that map to what I see in the content database in UserInfo.tp_Login.

Since I have enabled both Windows Authentication and Forms Based Authentication (claims) in my SharePoint 2010 web application I see values like the following for UserInfo.tp_Login.

<netbios_domain>\<samAccountName>
i:0#.w|<netbios_domain>\<samAccountName>
i:0#.f|<provider_name>|<claimsUserId>

For example:

MYDOMAIN\john.doe
i:0#.w|mydomain\john.doe
i:0#.f|ldapmember|john.doe@mydomain.com

Is there a good guide as to what the valid formats are here? I need to parse this information unless there is something handy function that I can use. I checked SPUtility and SPUtility.GetAccountName didn't seem to help.

I'm pretty sure that the "w" in "i:0#.w" means Windows and the "f" in "i:0#.f" means Forms, but I'm wondering if there is an enumerated list of possibilities somewhere.

Answer 1

Check out http://blog.mastykarz.nl/programmatically-converting-login-name-claim/

Yes, there's a handy function

Answer 2

There is an explanation in the whitepaper "Implementing Claims-Based Authentication with SharePoint Server 2010". You can download it here.

On page 62, "Claims Encoding", you read:

w/m/r/t/p/s = Original Issuer Type -> w = windows, m = membership, r = role, t = trusted STS, p = personal card, s= local sts claim

The rest of the string is explained too.

Update: I just found a full description on technet.