Magic cookie

In computer programming, a magic cookie or cookie is a token or short packet of data passed between communicating programs, where the data is typically not meaningful to the recipient program. The contents are opaque and not usually interpreted until the recipient passes the cookie data back to the sender or perhaps another program at a later time. The cookie is often used like a ticket - to identify a particular event or transaction.

For example, when one visits a website, the remote server may leave a cookie on one's computer, see HTTP cookie.

References