Alice and Bob n.
The archetypal individuals used as examples in discussions of
cryptographic protocols. Originally, theorists would say
something like: "A communicates with someone who claims to be B,
So to be sure, A tests that B knows a secret number K. So A sends
to B a random number X. B then forms Y by encrypting X under key
K and sends Y back to A" Because this sort of thing is is quite
hard to follow, theorists stopped using the unadorned letters A
and B to represent the main players and started calling them
Alice and Bob. So now we say "Alice communicates with someone
claiming to be Bob, and to be sure, So Alice tests that Bob knows
a secret number K. Alice sends to Bob a random number X. Bob then
forms Y by encrypting X under key K and sends Y back to Alice". A
whole mythology rapidly grew up around the metasyntactic names;
see http://www.conceptlabs.co.uk/alicebob.html.
In Bruce Schneier's definitive introductory text "Applied
Cryptography" (2nd ed., 1996, John Wiley & Sons, ISBN
0-471-11709-9) he introduces a table of dramatis personae headed
by Alice and Bob. Others include Carol (a participant in three-
and four-party protocols), Dave (a participant in four-party
protocols), Eve (an eavesdropper), Mallory (a malicious active
attacker), Trent (a trusted arbitrator), Walter (a warden), Peggy
(a prover) and Victor (a verifier). These names for roles are
either already standard or, given the wide popularity of the
book, may be expected to quickly become so.