How to Implement Secure (Mostly) Stateless Tokens
Eric Rescorla · 2007
A common protocol problem is to want to arrange to maintain client state with little or no local storage. The usual design pattern here is to provide the client with a token which is returned with subsequent interactions. In order to prevent tampering, forgery, and privacy issues, such tokens should be cryptographically protected. This draft describes one workable mechanism for constructing such tokens.