PDA

View Full Version : cryptography question--how to solve a Ceaser Cipher


jaggtagg7
Oct18-05, 11:16 PM
yeah, probably a very simple question i know, but we are at a loss of what to do. We havent been given any instruction on how to solve one, but the quest we were given is


The following message is a Caesar Cipher, a message encrypted by shifting each plaintext letter by a fixed amount:
TZWGWFNSNXFBTSIJWKZQRFHMNSJ
Find the deciphering key for this message and decipher the message.


question is how is this done with out methodically, trial and error, going through the alphabet and subsituting letters over and over again?

James R
Oct19-05, 03:52 AM
One way is to look at letter frequencies. For example, the most common letter in English is 'e', so if you take a long enough ciphertext encoded with the Caesar cipher, the most commonly repeated letter ought to correspond to "e".

If 'e' doesn't work, try other letters to replace the most common letter, in this order:

ETAOINSHRDLU

tHEService
Nov6-08, 12:46 PM
Hi there. wow old topic indeed.

here is the decoded ceaser shift

ourbrainisawonderfulmachine

The shift was by 5 characters.

Ciphertext alphabet : FGHIJKLMNOPQRSTUVWXYZABCDE

was bored.....