AWS for user management

AWS seem to have a pile of services now so I have been looking more closely at it.

I am looking for a centralized service where I can host user data and have them authenticate and secure different web applications, iphone apps both using custom logins and social logins such as Twitter/Google/Facebook.

An example flow would be that I have multiple websites coded in PHP and want users to login to these sites. But only users who have access. This user data, logins, access rights etc. needs to be hosted somewhere centralized and as much headache free as possible.

Instead of building my own platform for this that will support all the authentication and user management it would be nice to have this taken care of.

Does AWS have a service for this?

The IAM service seem to only deal with AWS access.

Notice I am not only talking about mobile apps but also websites.

I see there is a new service called Cognito, is this what I am looking for specifically in this use case?