Wednesday, August 3, 2011

Substitution Technique

This is another basic technique used to crypt data. It involves replacing a alphabet by another alphabet like replacing a with d , s with u, etc.

For a novice it is difficult to decrypt/decode the data on first go but there are techniques with which it can become easy.
The first step involves locating the high frequency letter in a given language. for example e,t and a are most used letters in English. So try replacing the letter with highest frequency in the given code with either of these characters.

For more information on frequency of letters
visit: http://en.wikipedia.org/wiki/Letter_frequency

Second step would be word recognition, if the words are spaced correctly the task becomes really easy like if a word contains a single letter , it could either be a or i. For a two letter word the options are or, at, an, etc. It requires some trial and error.

ALPHABET TO NUMBERS CIPHER

I have started with this one because it is the most basic of the cipher techniques.


How it works??
You donate a number to all the alphabets like 
A=1, B=2,....Z=26.

For example: the word "Inception"  would be coded like "91435162091514"

It seems simple but can get a bit tricky if the number is above 10 like 15 represents o and ae.
Here is a little program that lets you do this conversion






[ ALPHABET TO NUMBERS | NUMBERS TO ALPHABET ]


Convert your name or
message into Numbers

Please type your phrase in plain English



Convert Numbers back
into Alphabet

Separate each character with a space.
Separate each word with two or three spaces.