naveenprasanth/substitution-cipher

Implementation of substitution cipher

#Subtitution Cipher

This is the implementation of the famous , very old subtituion cipher using java .

1. Download the .zip file from the git hub and extract all the files into a Directory .

2. Make sure you have JDK ( Java Development Kit ) installled and configured right in your computer

3. Now create a file , "input.text" and write the content you want to encrypt inside that . Please use ony lower cases , spaces and period(.) symbol . This feature is yet to be optimised .

4. You will be provided with a subtition key in "key.text" .You can use this by default . If you want to change the key incase the key was stolen , change the key as per the following ,

   • Take a paper and write from a - z vertically
   • Now to the right of each alphabet write diffferent alphabets in a random order and make sure letters doesn't repeat
   • open key.text , you will find something like this "jnfmgehyzxbuaopiqwcdvkrs.t l"
   • Type the new sequence of yours .
   • Make sure you place "."(dot) and " " (space) in exactly same places .
   • Save the file under same name "keys.text"

5. Now compile the SubstitutionCipher.java using

   javac SubstitutionCipher.java

6. Execute the class file created by

   java SubstitutionCipher

7. Choose 1 do encrypt the content entered in input.text .

8. You can find a file encrypted.text created

9. Send the encrypted.text to a friend and share the key physically before hand .

10. You can decrypt the file using 2 option if you execute the program again . (Make sure key is present in the same directory )

11. Thanks

Ping me if you have suggestions where I could improve the code.

E-mail : [email protected]