in cryptography, “alice”, “bob”, etc. are used instead of “person A”, “person B”, etc. to make scenarios like “alice wants to send a message that bob can read but carol can’t” easier to read. by convention this practice extends to parties with special roles – “eve” is an eavesdropper, “mallory” is a malicious actor, etc. here’s the wikipedia article. anyway the xkcd joke can be read as using nerds’ interests in arcane algorithms to explain regular human interaction, humorously reversing the original utility of the convention, and the rest is basically your typical (affectionate) tumblr “but what if it was yuri” posting.
