A small data file passed from one program to another and sent back without change. Typically used in Unix systems, a magic cookie may be an identification token or password that activates a function. The "magic" implies some obscure data known only to the software and not the user. The Web cookie term was coined after magic cookie. See cookie.
(computing) A token or short packet of data passed between communicating programs, used to identify a particular event or transaction; the data is typically not meaningful to the recipient program and not usually interpreted until the recipient passes the data back to the sender or another program at a later time.
Origin of magic-cookie
By analogy with fortune cookie.