Social federation allows you to build your applications to request temporary credentials. Much like in the previous discussion relating to enterprise federation where we used SAML, these temporary credentials with social federation map to an AWS IAM role that has the relevant permission to access your DynamoDB database.
Instead of using your internal ADFS servers to authenticate users, the users of your app can use widely known social IdPs, for example, Facebook, Amazon, or Google. In fact, as long as the IdP is OpenID Connect (OIDC)-compatible, then you can use it for authentication. Using these social IdPs, the user can get an authentication token, which in turn is exchanged for temporary credentials, and these credentials are associated with your specific IAM role with the required permissions.
When creating applications that require social IdPs for authentication, you need to write specific code to interact with the IdP to allow you to call the AssumeRoleWithWebIdentity...
