substitution netwinz

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SUBSTITUTION CIPHER

Introduction:
In cryptography, a substitution cipher is a method of encryption by which units of plaintext are replaced with cipher text according to a regular system; the "units" may be single letters (the most common), pairs of letters, triplets of letters, mixtures of the above, and so forth. The receiver deciphers the text by performing an inverse substitution
There are a number of different types of substitution cipher. If the cipher operates on single letters, it is termed a simple substitution cipher; a cipher that operates on larger groups of letters is termed polygraphic.
Substitution over a single letter—simple substitution—can be demonstrated by writing out the alphabet in some order to represent the substitution. This is termed a substitution alphabet. The cipher alphabet may be shifted or reversed (creating the Caesar and Atbash ciphers, respectively) or scrambled in a more complex fashion, in which case it is called a mixed alphabet or deranged alphabet.




HOW TO CONDUCT THE EXPERIMENT:
Click on Presentation Layer on the Main Window and Then Select "SUBSTITUTION CIPHER" Module from the Modules displayed in the centre of the window.
SUBSTITUTION CIPHER Window will open up as shown in SNAPSHOT-1.

SNAPSHOT-1
TRANSMITTER:

1. Enter the "IP Address" of the computer to which you intend to send data.
2. Enter the Key for Encryption. The key value is between 1 and 26.
3. Enter the Data that needs to be encrypted in the "TEXT" textbox.
4. Click on "ENCRYPT" button to encrypt the data.
The table displays the entire Substitution Cipher Table as shown in SNAPSHOT-2.
The Encrypted Data is shown in the "ENCRYTED TEXT" textbox.

5. Click on the "SEND" button to send the encrypted Data to the destination IP.

SNAPSHOT-2


Use Loop back Address "127.0.0.1" to send the Data to the same computer.




RECEIVER:
In the Receiver Window, the Encrypted Data is displayed in the "ENCRYTED TEXT" text box as soon as the data is received as shown in SNAPSHOT-3.

SNAPSHOT-3

1. Enter the Key value same as entered on the server in the "KEY" textbox.
2. Click on "DECRYPT" button to decrypt the data. The Decrypted data is shown in the "TEXT" textbox on the receiver as shown in SNAPSHOT-4
And the Subsitution Cipher Table is shown in the table at the bottom of the Receiver Window.




SNAPSHOT-4
Transmitter and Receiver Messages are Displayed in the "Message Window" on the extreme right.
Reset Button:
Click On "RESET BUTTON" to reset all the controls to initial values.
Click on "HELP BUTTON" to Open SUBSTITUTION CIPHER Manual.
Click on "EXIT BUTTON" To Close SUBSTITUTION CIPHER Window.


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