#2691: Encryption

XKCD comic, described below.
Transcript

[Cueball showing a phone to a long-haired woman, identified in the caption as Alice]

Cueball: The app will let you send messages to your friend Robert, or my brother.

Alice: Can they reply?

Cueball: No.

[Caption below the panel]:

My new secure texting app only allows people named Alice to send messages to people named Bob.


(Sourced from explainxkcd.com)

Title text:WARNING: PEOPLE NAMED EVE ARE PROHIBITED FROM INSTALLING THIS APP!


ExplainOriginal