1578: Squirrelphone

2015-09-16T04:55:56Z

KennethBell:

{{comic
| number = 1578
| date = September 16, 2015
| title = Squirrelphone
| image = squirrelphone.png
| titletext = After a while, the squirrel starts making that beeping noise and doesn't stop until it hops back up onto the stump.
}}

==Explanation==
This is a joke about Squirrelmail, a web-based email client that was for many early users their first webmail service. Before Squirrelmail, users had to check email by opening a terminal via telnet or dowloading it via SMTP. Organizations enabling it in their servers allowed their users as well to check mail from any web browser, even in a setting like Iternnet cafés where telnet or email clients were not available.

While Squirrelmail was an existent service, there has never existed a "Squirrel-phone" or similar sevice, a living squirrel being not an appropiate creature to mantain a phone call.

Is there here people young enough not to know the tones of the POTS (Plain Old Telephone Service)?
"Riing, Riing" is the calling tone - someone is calling you
The beeping noise of the alt text "bip bip bip bip" means that a call is not established and not available because the receiver is up.

==Transcript==
{{incomplete transcript}}

{{comic discussion}}

Sometimes I wonder if the joke is to make ExplainXKCD squirm.

1553: Public Key

2015-07-21T18:45:03Z

KennethBell: /* Explanation */

{{comic
| number = 1553
| date = July 20, 2015
| title = Public Key
| image = public_key.png
| titletext = I guess I should be signing stuff, but I've never been sure what to sign. Maybe if I post my private key, I can crowdsource my decisions about what to sign.
}}

{{Incomplete| first draft}}
==Explanation==

In [https://en.wikipedia.org/wiki/Public-key_cryptography Public-key cryptography], two keys are generated for a user. The public key can be used to encrypt messages, but not decrypt them. The private key is necessary for decryption, and as its name implies, is meant to be used solely by the user.

Since the public key is initially designated to be shared, anyone who has that key can send the user an encrypted message that only he or she can decrypt. Cueball has been following this rule, but he notices that it appears nobody has ever used his public key for anything. He contemplates sharing his ''private'' key, which he believes would generate more interest in him personally. However, he appears to overlook the fact that doing so would allow anyone to decrypt messages sent to him, thus defeating the entire purpose of encryption.

If Cueball had initially released his private key instead of his public one, it would make no difference, since the importance is in keeping one key private - the keys themselves do not hold "private" or "public" roles until one is released and becomes the public key. However, since Cueball has already released his public key, releasing his private key would compromise the key pair. Even if he attempted to remove records of his public key, chances are that some sites would still have it somewhere.

The title text refers to another feature of Public-key cryptography: In addition to assuring that certain messages can only be read by a specific key owner, it can also assure that certain messages could only have been ''written'' by a specific key owner, by "signing" it using the private key. Anyone can read a signed message, but readers with the public key can then verify that the owner of the private key wrote (or at least signed) the message, rather than someone pretending to be the owner. If Cueball published his private key, then anybody could sign any message as him, effectively impersonating him and also defeating the purpose of encryption.

{{w|Crowdsourcing}} is the term used for delegating work or tasks to a largely volunteered and uncontrolled set of people on the Internet. It is similar in concept to {{w|outsourcing}}, in which work is delegated to an external source of labor, typically a company in a foreign country. Famous instances of crowdsourcing include {{w|reCAPTCHA}} (in which users both verify they are human and help digitize words and phrases in books that digitization software cannot understand) and [http://www.ideaconnection.com/open-innovation-success/Crowdsourcing-Down-on-the-Farm-00304.html a farm in the UK] in which ordinary Internet users make decisions about how the farm is run. In Cueball's case, delegating decisions about his contracts and spending to the Internet is not likely to be a wise choice.

When Cueball first created the key pair, he imagined it would be something he used from time to time, for reading messages only intended for him or for sending "signed" messages. Since nothing of the sort happened, he imagines releasing both keys might cause some activity, and at this point he is happier with a "bad" outcome than with a boring one.

Randall previously ironically mentioned a public key in [http://www.explainxkcd.com/wiki/index.php/370 370: Redwall].

==Transcript==
[In the first panel, Cueball is sitting in a chair and is using a laptop.]

Cueball: I've been posting my public key for 15 years now, but no one has ever asked me for it or used it for anything as far as I can tell.

[Two panels with Cueball thinking silently.]

Cueball: Maybe I should try posting my ''private'' key instead.

{{comic discussion}}

[[Category:Cryptography]]
[[Category:Comics featuring Cueball]]

explain xkcd - User contributions [en]

1578: Squirrelphone

1553: Public Key