Federated authentication of client computers in networked data communications services callable by applications

One or more non-transitory computer-readable storage media storing one or more sequences of instructions which when executed by one or more computing devices cause performing a method providing improved and efficient authentication of client computers by server computers, the method comprising:

• using authentication logic of a server computer, establishing a secure socket connection with a first client computer that is executing a first application associated with a first provider computer, and a second client computer that is executing a second application associated with a second provider computer;
• receiving, from the first application of the first client computer, a request to use a communications service that is implemented at the server computer, and in response to the request, determining that the first client computer is unauthenticated;
• providing a nonce value to the first client computer;
• receiving from the first client computer an encrypted identity token that includes the nonce and a user identifier, wherein the identity token has been encrypted using the first provider computer and an encryption key of the first provider computer, wherein the encryption key is known at the server computer;
• validating the identity token and obtaining the user identifier therein;
• creating and storing a session token that is uniquely associated with the first client computer and that includes a session identifier, the user identifier, and a binding to the secure socket connection;
• receiving, from the second application of the second client computer, a second request to use the communications service that is implemented at the server computer;
• providing the communications service to the first client computer for communication using the first application in response to the first request, and providing the communications service to the second client computer for communication using the second application in response to the second request, wherein the communications service comprises messaging, voice, or video.