Since the late 1970s, cryptographers have been using personal names (instead of labels like “person A” and “person B”) to describe various communications scenarios. Many of these scenarios involve two communicating parties named Alice and Bob and an eavesdropper named Eve.
Extra parties are assigned names alphabetically (e.g., Carol, Dave) unless they play a specific role within the scenario. For instance, a password cracker is named Craig, a malicious attacker is named Mallory, an intruder is named Trudy, and a whistle-blower is named Wendy.
In zero-knowledge protocols, the “prover” and “verifier” of a message are typically named Peggy and Victor…but Pat and Vanna (after Wheel of Fortune presenters Pat Sajak and Vanna White) are sometimes used instead.
Here’s more about Alice and Bob from American cryptographer Bruce Schneier:
And you’d see paper after paper, and [in] the opening few paragraphs, the authors would explain what they’re doing in terms of Alice and Bob. So Alice and Bob have a storied history. They send each other secrets, they get locked in jail, they get married, they get divorced, they’re trying to date each other. Anything two people might want to do securely, Alice and Bob have done it somewhere in the cryptographic literature.
Question of the day: If you were tasked with updating the names of “person A” (female) and “person B” (male), what new names would you choose?
Sources:
- Alice and Bob – Wikipedia
- Leyden, John. “‘Replace crypto-couple Alice and Bob with Sita and Rama’.” Register 1 Oct. 2012.
- Bruce Schneier – Who are Alice & Bob? [vid]
Image: Protocol by Randall Munroe under CC BY-NC 2.5.
