This document discusses several symmetric and asymmetric ciphers. It describes Caesar cipher, Vigenere cipher, transposition cipher, one-time pad, and RSA cipher. For each cipher it provides a brief overview of the encryption process and includes examples to demonstrate how the cipher works. It aims to educate the reader about common cryptographic tools and techniques.

1. CRYPTO TOOLS
By T Naga Srimanyu (12MCMB06)

2. Symmetric Ciphers

3. Some of them include..
 Caesar cipher
 Vigenere cipher
 Transposition cipher
 One-time pad & Vernam cipher

4. Caesar cipher
 Character shifting is done by using a value in
‘k’.
 Shifting is performed on the alphabet string.

5. Eg..
 Plain text = ‘hey whts up guys’
 Value in K = 3
 Cipher = ‘khb zkwv xs jxbv’

6. Demonstration

7. Vigenere Cipher
 We use a key to generate the cipher from the
plain text.
 The plain text character are mapped with the
characters in the key to get a new
character(cipher element).
 The matrix is just a collection of letters in the
alphabet as shown in figure.

9. Demonstration

10. Transposition Cipher
 The characters in the plain text are rearranged
based on a key.
 That is the position of the characters are just
jumbled.

11. Eg.
 Key: 1234
 Text: heyI
amab
oy .
 Cipher: haoemyya.lb

12. Demonstration

13. OTP/Vernam
 The length of the key should be same as the
length of the plain text.
 If not the key is repeated (vernam).
 Each character in the key is XOR’ed with the
each character in the plain text.

14. Demonstration

15. One Asymmetric Cipher

16. RSA
 Steps involved…
 Selecting two large prime numbers.
 Resolving ‘n’.
 Using Euler’s totient function,Φ(n).
 Then getting the public and private keys(‘e’ and
‘d’).
 Encryption (Public): ((plain text)^e)mod n
 Decryption (Private): ((plain text)^d)mod n

17. Demonstration

18. Thank You