1121: Identity

2012-10-15T14:26:04Z

72.71.205.39: /* Explanation */

{{comic
| number = 1121
| date = October 15, 2012
| title = Identity
| image = identity.png
| imagesize =
| titletext = Not sure why I just taught everyone to flawlessly impersonate me to pretty much anyone I know. Just remember to constantly bring up how cool it is that birds are dinosaurs and you'll be set.
}}

==Explanation==

Cueball lost the server password and is asking Megan what it is. Megan correctly comments, that she can't be sure, through text-based messages, that it's really Cueball asking for the password - it could be someone impersonating him in an attempt of [http://en.wikipedia.org/wiki/Social_engineering_%28security%29 Social Engineering]. Cueball answers by starting to develop a cryptographic protocol they can use for proof of identity, probably something like [https://en.wikipedia.org/wiki/Off-the-Record_Messaging OTR Messaging] as implemented in many XMPP chat clients or [http://en.wikipedia.org/wiki/Feige%E2%80%93Fiat%E2%80%93Shamir_identification_scheme Feige–Fiat–Shamir identification scheme] (in reality, it would already be too late for that - they should have prepared something beforehand). Before he even finishes, Megan answers "It's you", meaning that no one else is so geeky that they would answer like that. Cueball wants to stop her [probably because he would really enjoy that proof of identity construction]. The use of 2 random numbers provide encryption so that other people will not be able to eavedrop; it does not provide authentication, the ability to verify the person you are talking to. [Can someone with more encryption/security knowledge confirm this?]

In the title text, [[Randall Munroe|Randall]] suggests that this is, in fact, his own personality, and that anyone reading the comic can now impersonate him. For a bonus, he notes his own fascination with the fact that birds are descendants of dinosaurs, which one could use to impersonate him as well.

Notably, although the characters appear to be communicating by way of text (whether SMS, or some instant messaging protocol), it Megan should not be able to interrupt Cueball. Text-based messages do not typically stream in realtime as they are typed. She wouldn't be able to read his message until he completed it and sent it.

{{Incomplete}}

==Transcript==
:Cueball: Hey, I lost the server password. What is it, again?

:Megan: It's— ...Wait. How do I know it's really you?

:Cueball: OOH, good question! I bet we can construct a cool proof-of-identity protocol. I'll start by picking two random—
:Megan(on phone):Oh good; it's you. Here's the password...
:Cueball: NO!

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]

explain xkcd - User contributions [en]

1121: Identity