Disclosed is a method for user identity authentication for a peer device joining a peer-to-peer overlay network. In the method, a credential server of the overlay network receives a registered user identity from a joining peer device. The credential server verifies the registered user identity with an identity provider. Upon receiving, at the credential server, successful verification of the registered user identity from the identity provider, the credential server issues to the joining peer device a signed certificate for use by an authenticated peer device in the overlay network to authenticate the registered user identity of the joining peer device, wherein the signed certificate is signed by a private key of the credential server.