Who are Alice and Bob?

Question

Simply: who are Alice and Bob, and why are they mentioned in every Bitcoin-related article I read about that talks about Bitcoin transactions?

What is the history or mystery of these two?

Answer 1

Fictional characters. Cryptography (and other) books use names like that often.

http://en.wikipedia.org/wiki/Alice_and_Bob

Answer 2

Alice and Bob are placeholder characters corresponding to the letters of the alphabet. They are used especially in computer science to describe use-cases or scenarios. The scheme is used because it's more convenient to say "Alice sends money to Bob" than to say "Party A sends money to Party B". As each name has a different initial, diagrams can fall back to single letter labeling.

It's a well-known meme:

^{via xkcd.com}

The list usually goes something like this: Alice, Bob, Charlie, Dave, Erin, Frank,…

Other names are used to represent attacker types or other recurring roles:

• Carole, the oracle
• Eve, the eavesdropper
• Mallory, the man-in-the-middle attacker with malicious intent
• Sybil, the attacker with lots of identities
• Trent, the trusted entity