Alice and Bob
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 Alice and Bob; 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.
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