Fictional characters to arrange key exchange over unsecure channel?

July 21, 2014 6:29 PM

I'm presenting a cryptography demonstration to a small group of nerdy teenagers soon. As part of the fun, I have an activity in which they are spies that need to arrange a key exchange over a unsecure channel without any required prior knowledge of each other. (You can assume the mechanics of the key exchange are sound.) I thought it might be fun if I could refer to different fictional characters that the teens could pretend to be. What are some fictional characters and associated unsecure channels that would fit the scenario above? Examples and further notes inside.

The activity I'm using is susceptible to Man in the Middle Attacks (pretending to be the other person to both parties in order to gain access to the information), so naming the character or entity that might serve as the man in the middle would be a bonus.

The characters can certainly know each other, but don't *have* to know anything about each other, except that they'll be performing this key exchange.

Here're a couple examples I've come up with:
Aurors from Harry Potter, via owls, Man in the Middle could be a set of Death Eaters
Agents of SHIELD/Avengers, via facebook or other common social networking site, Man in the Middle: HYDRA

Assume that the teens who are hearing this presentation are from or have spent significant time in the USA.

Thanks!

posted by wiskunde to Grab Bag (11 answers total)

Alice, Bob, Eve, Mallory and the gang are kind of traditional for this scenario, but that may not be interesting enough for your kids. What about Neo, Trinity, Agent Smith etc. from The Matrix?
posted by uosuaq at 6:50 PM on July 21, 2014

Two kids using their actual names, and instead of Mallory you have "Mom".
Alfred, Batman, and pick-a-baddie.
Master Chief, Cortana, and The Flood.
Anna, Elsa, and Prince Hans.
posted by bfranklin at 6:58 PM on July 21, 2014

Haha, the Matrix is actually like super out of date now.

My suggestion: Katniss from the hunger games needs to get a message to a contestant she doesn't know, susceptible to interception from any of the other contestants.
posted by kavasa at 7:00 PM on July 21, 2014 [5 favorites]

Alternatively it could be two agents of the rebellion that need to identify each other, evading interception by agents of President Snow. Messages to be sent by little robots or something.
posted by kavasa at 7:01 PM on July 21, 2014

Older teens might recognize Sterling, Cyril, Lana, and Mallory. The man in the middle is Barry.
posted by Rock Steady at 7:13 PM on July 21, 2014 [1 favorite]

One thing I like about the traditional names that uosuaq mentioned is that several of them have mnemonic properties - Eve is an eavesdropper, Mallory is a malevolent attacker, and so on, depending on how far into the complex scenarios you're going to go.

Maybe I'm just nerdier than most, and depending on their age and personality of course, but I would think bright teenagers would like being let in on these "secrets of the guild," and might feel a bit patronized by cartoon characters and such.
posted by randomkeystrike at 7:26 PM on July 21, 2014 [7 favorites]

Diffie and Hellman?
posted by dilaudid at 9:18 PM on July 21, 2014

You would be doing them a service by at least explaining the convention concerning Alice, Bob, et al., even if you go on to use different choices for your demonstration.
posted by Nerd of the North at 9:48 PM on July 21, 2014 [1 favorite]

The Wikipedia Page on the the traditional use of Alice and Bob also lists the full set of standard characters. What is interesting is that, in choosing Alice and Bob, Ron Rivest was apparently also trying to hold his audience's attention by referring to the 1969 film Bob & Carol & Ted & Alice (where Bob and Alice have an affair).
posted by rongorongo at 3:55 AM on July 22, 2014 [1 favorite]

...and as Nerd of the North says, the intention of using the names was always to help humanize what would otherwise be mathematical variables. The message is being passed from A to B, there may be others (C...E...) involved in the conversation, an evesdropper E and a person with malicious intent M etc. To maintain the spirit of the convention your names should start with these letters - perhaps you could let members of your class choose them with this proviso.

See also "Alice and Bob - Security's inseparable couple"
posted by rongorongo at 4:07 AM on July 22, 2014

Oh - and the final element, apart from the names, is a back story: Alice and Bob need to have a reason to talk to each other and a fleshed out context that describes their conversation. This is what John Gordon provided in this 1984 after dinner speech - Alice has never met her stockbroker, Bob - she does not really trust him and she is happy to try to get him confidential information over a noisy phone line which is probably tapped. She also wants to save money by keeping the conversation short.

The modern equivalent would be a reality TV star tweeting her credit card number to her plastic surgeon over the overpriced wifi connection of a hotel room owned by News International.
posted by rongorongo at 4:35 AM on July 22, 2014