web based applications for encryption using substitution and transposition techniques

1. Sanjivani Rural Education Society’s
Sanjivani College of Engineering, Kopargaon
(An Autonomous Institute Affiliated to Savitribai Phule Pune University)
Cyber Security CIA Presentation On
“Web based Application for Encryption using Substitution and Transposition Techniques”
Presented By
Ms. Mahajan Vaishnavi (82)
Ms. Bornare Gauri (83)
Ms. Nagpure Latika (84)
Ms. Bornare Anjali (86) Prof. M. Agrawal Mam
(Subject Teacher)
Department of Computer Engineering

2. Problem Statement
The problem that the Web-based application for encryption using substitution and transposition techniques
project aims to solve the need for a secure way of transmitting and storing sensitive information over the internet.
With the increasing use of the internet, there is a significant risk of sensitive information being intercepted by
unauthorized parties, which can lead to severe consequences such as identity theft, financial loss, and privacy
breaches. Therefore, there is a need for a secure way of transmitting and storing sensitive information over the
internet.

3. Objectives
● To develop a user-friendly web-based application that allows users to encrypt sensitive information using
substitution and transposition techniques.
● To make encryption techniques accessible to users who may not have specialized knowledge or skills in
computer science or cryptography.
● To implement substitution and transposition techniques to increase the security of messages and protect them
from interception by unauthorized parties.

4. Substitution
Substitution involves replacing each letter or character in the plaintext with a corresponding letter or
character from a substitution table. The substitution table contains a set of predefined mappings between letters or
characters in the plaintext and ciphertext. For example, in a simple substitution cipher, every occurrence of the letter
'A' in the plaintext could be replaced with the letter 'X' in the ciphertext, and so on.
Substitution Techniques:
1. Caesar Cipher
2. Playfair Cipher

5. 1. Caesar Cipher
A Caesar cipher is a simple method of encoding messages. Caesar ciphers use a substitution method where letters in
the alphabet are shifted by some fixed number of spaces to yield an encoding alphabet. A Caesar cipher with a shift
of 1. 1 would encode an A as a B, an M as an N, and a Z as an A, and so on.
The formula of encryption is:
En (x) = (x + n) mod 26
Example
Plain Text: Security
Key: 3

6. Solution:
Key: 3
Cipher Text: VHFXULWB
Plain Text S → 18 En = (18+ 3) mod 26 Cipher Text 21 → V
Plain Text E → 04 En = (04+ 3) mod 26 Cipher Text 07 → H
Plain Text C → 02 En = (02+ 3) mod 26 Cipher Text 05 → F
Plain Text U → 20 En = (20+ 3) mod 26 Cipher Text 23 → X
Plain Text R → 17 En = (17+ 3) mod 26 Cipher Text 20 → U
Plain Text I → 08 En = (08+ 3) mod 26 Cipher Text 11 → L
Plain Text T → 19 En = (19+ 3) mod 26 Cipher Text 22 → W
Plain Text Y → 24 En = (24+ 3) mod 26 Cipher Text 27 → B

7. 2. Playfair Cipher
Playfair cipher is an encryption algorithm to encrypt or encode a message. It is the same as a traditional
cipher. The only difference is that it encrypts a digraph (a pair of two letters) instead of a single letter. The Playfair
cipher is the earliest and best-known digraph substitution cipher to use symmetry encryption.
Example
Plain text: Hide the key
Key: Playfair

8. Solution
Step 1: 5 X 5 Matrix
Step 2: Pair of two letters:
Hi de th ek ey

9. Step 3:
Cipher Text: ebimqmgmkp

10. Transposition
Transposition involves rearranging the order of the characters or letters in the plaintext to form the
ciphertext. In transposition, the position of the letters in the plaintext is changed to create the ciphertext. For
example, a transposition cipher might rearrange the order of the letters in the plaintext message so that the letter in
the first position is moved to the third position, the letter in the second position is moved to the fifth position, and so
on.
Transposition Techniques:
1. Rail Fence Transposition
2. Simple Columnar

11. 1. Rail Fence Transposition
The rail fence cipher (sometimes called zigzag cipher) is a transposition cipher that jumbles up the order of
the letters of a message using a basic algorithm.
The rail fence cipher works by writing your message on alternate lines across the page, and then reading off
each line in turn.
Example
Plain text: Security
Key: 2

12. Solution:
Cipher text: scrteuiy

13. 2. Simple Columnar Transposition
The columnar transposition cipher is a fairly simple, easy to implement cipher. It is a transposition cipher that
follows a simple rule for mixing up the characters in the plaintext to form the ciphertext.Although weak on its own,
it can be combined with other ciphers, such as a substitution cipher, the combination of which can be more difficult
to break than either cipher on it's own.
Example
Plain text: Security
Key: key

14. Solution:
Cipher Text: erysutci_

15. Output
Fig. Caesar Fig. Playfair
Fig. Simple Columnar
Fig. Rail Fence

16. Applications
● Military communication
● Online transactions
● Email encryption
● Password protection
● Digital signature
● Secure messaging apps

17. Conclusion
In conclusion, the system that uses the concepts of transposition and substitution for encrypting the messages
using Rail fence, Playfair cipher, Caesar cipher, and Simple Columnar Transposition is a secure and effective
method of ensuring the confidentiality and privacy of sensitive information. Overall, the use of a combination of
these above ciphers in a system ensures that the message is encrypted in a way that is difficult to crack without the
key.

18. References
● https://www.tutorialspoint.com
● https://geeksforgeeks.com
● https://www.javatpoint.com

19. Thank You..!!