substitution and transposition techniques_ppt.pptx

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: Caesar Cipher Playfair Cipher

5. 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: E n (x) = (x + n) mod 26 Example Plain Text: Security Key: 3

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

11. 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..!!