Irregular Webcomic!

Archive     Cast     Forum     RSS     Books!     Poll Results     About     Search     Fan Art     Podcast     More Stuff     Random     Support on Patreon    
Updates: Monday, Tuesday, Thursday, Friday; reruns all other days
<   No. 1629   2007-07-13   >

Comic #1629

1 Wendy: We be free o' our pursuers, cap'n!
2 Long Tom: That be good. Now, let's be seein' what we can be makin' o' this map.
3 Long Tom: Hmmm. It be writ in an ancient hand, usin' a long forgotten secret pirate cipher, but I can be readin' some o' it.
4 Wendy: How so, cap'n?
4 Long Tom: I be studyin' arrrchaic languages!

First (1) | Previous (1628) | Next (1630) || Latest Rerun (1622) | Latest New (3734)
First 5 | Previous 5 | Next 5 | Latest 5
Pirates theme: First | Previous | Next | Latest || First 5 | Previous 5 | Next 5 | Latest 5
This strip's permanent URL:
Annotations off: turn on
Annotations on: turn off

A cipher is different from a (cryptographic) code. The basic difference is that codes transform information at the semantic level, whereas ciphers transform it at the lexicographic level.

To illustrate: If you wanted to send the message "The treasure is in Tortuga" in a code, you'd need a codebook with pre-agreed encodings of the ideas of "treasure" and "Tortuga" at the very least. If "treasure" maps to "bananas" and "Tortuga" maps to "the moon", then your encoded message would be "The bananas are on the moon". The person receiving your coded message would need to know that the bananas refer to treasure, and the moon refers to Tortuga. Anyone who didn't know those mappings would have no idea what the message was really about, and no conceivable way to discover the meaning from the message itself. (To break such a code, you basically need to steal the codebook or interrogate someone who knows it.)

On the other hand, if you wanted to send the same message by a cipher, you'd apply some sort of pre-agreed mapping to the letters in the message. An example might be to reverse the words and replace each letter with the next letter of the alphabet, which yields: "fiu fsvtbfsu tj oj bhvuspu". Ciphers may look less comprehensible, but they are more liable to be broken using no information but that contained in the message itself. In this case, the letter "f" appears several times. The most common letter in English text is "e", so we might guess that "f" represents "e" - which in this case is true. A variety of such techniques can crack pretty much any cipher invented before about 1950 and the advent of computer cryptography.

LEGO® is a registered trademark of the LEGO Group of companies, which does not sponsor, authorise, or endorse this site.
This material is presented in accordance with the LEGO® Fair Play Guidelines.

Irregular Webcomic! | Darths & Droids | Eavesdropper | Planet of Hats | The Prisoner of Monty Hall
mezzacotta | Lightning Made of Owls | Square Root of Minus Garfield | The Dinosaur Whiteboard | iToons | Comments on a Postcard | Awkward Fumbles
Last Modified: Friday, 13 July 2007; 03:11:02 PST.
© 2002-2017 Creative Commons License
This work is copyright and is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported Licence by David Morgan-Mar.