aparler/RosettaCodeData
1
0
Fork 0
Code Issues 12 Pull requests 3 Projects Releases Packages Wiki Activity Actions

2016 Update

Browse source
This commit is contained in:
Tina Müller 2016-12-05 22:15:40 +01:00
parent 948b86eafa
commit dcf5d15da3
7965 changed files with 139854 additions and 31002 deletions
Download patch file Download diff file Expand all files Collapse all files

11
Task/Caesar-cipher/00DESCRIPTION
View file

@ -1,17 +1,20 @@
;Task:
Implement a [[wp:Caesar cipher|Caesar cipher]], both encoding and decoding. <br>
The key is an integer from 1 to 25.
This cipher rotates (either towards left or right) the letters of the alphabet (A to Z).
The encoding replaces each letter with the 1st to 25th next letter in the alphabet (wrapping Z to A). So key 2 encrypts "HI" to "JK", but key 20 encrypts "HI" to "BC".
The encoding replaces each letter with the 1st to 25th next letter in the alphabet (wrapping Z to A).
<br>So key 2 encrypts "HI" to "JK", but key 20 encrypts "HI" to "BC".
This simple "monoalphabetic substitution cipher" provides almost no security, because an attacker who has the encoded message can either use frequency analysis to guess the key, or just try all 25 keys.
This simple "mono-alphabetic substitution cipher" provides almost no security, because an attacker who has the encoded message can either use frequency analysis to guess the key, or just try all 25 keys.
Caesar cipher is identical to [[Vigenère cipher]] with a key of length 1. <br>
Also, [[Rot-13]] is identical to Caesar cipher with key 13.
;See also:
;Related tasks:
* [[Rot-13]]
* [[Substitution Cipher]]
* [[Vigenère Cipher/Cryptanalysis]]
<br>
<br><br>