Methods of Encryption
The two main methods of encryption are Substitution and Transposition
and most known modern methods are a mixture of both.
- Substitution : When individual letters or n-grams of plaintext
are replaced by letters or n-grams of ciphertext.
ie: replace any letter in a string with its following letter in the alphabet (also known as Ceasar substitution)
hello ... ifmmp
ie: replace all instances of "tim" with "freak"
hello tim, what time is it? ... hello freak, what freake is it?
- Transposition : when the characters of the original message are
rearranged according to some particular pattern.
ie: reverse the order of all the characters in the string
hello ... olleh
An example of both methods combined (substitution then transposition>:
ie: replace any instances of "tim" with "freak" then reverse the order of all the characters in the string
hello tim, what time is it? ... hello freak, what freake is it? ... ?ti si ekaerf tahw ,kaerf olleh
n-gram - A string of n-letters.
Copyright 1997 by Slackers Union. Comments should go to any of the
group members. Opinions reflected on this page are by no means
opinions
of UCSD. Go sue somebody else.
Last Modified: June 1, 1997
|