Abstract: A data processing method providing message synchronization, the method comprising: maintaining, by a server computer implementing a communications service, a stream of events comprising a plurality of members, the stream of events representing a thread of communication between the plurality of members, wherein each event in the stream comprises a sequence number; receiving, by the server, a request to synchronize a local state of a client computer, wherein the client computer is associated with a member of the plurality of members; sending a plurality of new events to the client computer using sequence numbers of the stream of events, wherein the client computer represents the thread of communication as conversations; receiving, by the server, a conversation object comprising a temporary identifier from the client computer; assigning, by the server, a globally unique identifier to the conversation object; notifying, by the server, the plurality of members of the conversation object.

Abstract: A data processing 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 client computer; receiving, from the 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 client computer is unauthenticated; providing a nonce value to the client computer; receiving from the client computer an encrypted identity token that includes the nonce and a user identifier, wherein the identity token has been encrypted using a provider computer and an encryption key of the 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 client computer and that includes a session identifier, the user identifier,

Abstract: A data processing 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 client computer; receiving, from the 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 client computer is unauthenticated; providing a nonce value to the client computer; receiving from the client computer an encrypted identity token that includes the nonce and a user identifier, wherein the identity token has been encrypted using a provider computer and an encryption key of the 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 client computer and that includes a session identifier, the user identifier,