Alice and Bob are placeholder names which are commonly used to talk about problems. It is used in cryptography, game theory and physics. Instead of “A sends B a message” people say “Alice sends Bob a message”. Ron Rivest seems to have used these names first, in publications about the RSA algorithm. This was 1977 and 1978.
Other names[change | change source]
The most used names are Alice and Bob. Eve, Mallory, and Trent are used often too, and they have pretty well-defined uses.