If you go to http://dev.live.com/liveid you’ll see links to Windows Live ID for Web Authentication and Client Authentication which enable developers to build Web or desktop applications that can be used to authenticate users via Windows Live ID. The desktop SDK are still in alpha but the Web APIs have hit v1. You can get the details from the Windows Live ID team blog post entitled Windows Live ID Web Authentication SDK for Developers Is Released which states
Windows Live ID Web Authentication allows sites who want to integrate with the Windows Live services and platform. We are releasing a set of tools that make this integration easier than ever. Web Authentication works by sending your users to the Windows Live ID sign-in page by means of a specially formatted link. The service then directs them back to your Web site along with a unique, site-specific identifier that you can use to manage personalized content, assign user rights, and perform other tasks for the authenticated user. Sign-in and account management is performed by Windows Live ID, so you don't have to worry about implementing these details. Included with the Web Authentication software development kit (SDK) are QuickStart sample applications in the ASP.NET, Java, Perl, PHP, Python, and Ruby programming languages. You can get the sample applications for this SDK from the Web Authentication download page>on Microsoft.com.
Windows Live ID Web Authentication allows sites who want to integrate with the Windows Live services and platform. We are releasing a set of tools that make this integration easier than ever.
Web Authentication works by sending your users to the Windows Live ID sign-in page by means of a specially formatted link. The service then directs them back to your Web site along with a unique, site-specific identifier that you can use to manage personalized content, assign user rights, and perform other tasks for the authenticated user. Sign-in and account management is performed by Windows Live ID, so you don't have to worry about implementing these details.
Included with the Web Authentication software development kit (SDK) are QuickStart sample applications in the ASP.NET, Java, Perl, PHP, Python, and Ruby programming languages. You can get the sample applications for this SDK from the Web Authentication download page>on Microsoft.com.
As one of the folks who's been championing opening up our authentication platform to Web developers, this is good news. I'm not particularly sold on using Windows Live ID as a single sign-on instead of sites managing their own identities but I do think that now that we allow non-Microsoft applications (e.g. mashups, widgets, etc) to act on behalf of Windows Live users via this SDK, there'll be a burst of new APIs coming out of Windows Live that will allow developers build applications that manipulate a user's data stored within Windows Live services.
Opening up our platform will definitely be good for users and will be good for the Web as well. Kudos, to the Windows Live ID folks for getting this out.
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