Rotor Cipher and Enigma Machine

This presentation explains cipher technique with the help of an example and also explains components and the working of enigma machine.

1. ROTOR CIPHER & ENIGMA MACHINE BY : SAURABH KAUSHIK (3174) Sarvesh rawat (3121)

2. Taxonomy of Cryptology

3. Rotor cipher A Rotor machine is an electro-mechanical stream cipher device used for encrypting and decrypting secret messages. A Stream cipher is a symmetric key cipher where plaintext digits are combined with a pseudorandom cipher digit stream ( keystream ). In a stream cipher each plaintext digit is encrypted one at a time with the corresponding digit of the keystream , to give a digit of the cipher text stream.

4. Monoalphabetic vs. Polyalphabetic Monoalphabetic cipher uses fixed substitution over the entire message. Polyalphabetic cipher uses a number of substitutions at different positions in the message, where a unit from the plaintext is mapped to one of several possibilities in the cipher text and vice versa.

5. A Rotor

6. Example Assumptions:- A rotor which is designed for first 7 alphabet. Plaintext of length 5. Upward rotation.

7. Example A B C D E F G A 1 B 1 C 1 D 1 E 1 F 1 G 1 Starting Configuration Of Rotor

8. Example A A A A A A A A A A B B B B B B B B B B C C C C C C C C C C D D D D D D D D D D E E E E E E E E E E F F F F F F F F F F G G G G G G G G G G Rot. 1 Rot. 2 Rot. 3 Rot. 4 Rot. 5

9. Example Suppose, Plain text= DCEGF D E C D E D G A F G Cipher Text = EDDAG Encryption Procedure :

10. Example Revert back the steps followed in encryption procedure! Decryption Procedure :

11. ENIGMA MACHINE

12. Enigma Technology Typewriter style cipher machine was a major advance in ease of use and cryptologic strength Innovation was the electro-mechanical rotors Rotors turn odometer style, giving a new cipher algorithm for each letter in a message No printing capability

13. Keyboard

14. Plugboard The Enigma machine had several cables with a plug at each end that could be used to plug pairs of letters together . If A were plugged to B then, on typing the letter A, the electric current would follow the path that was normally associated with the letter B, and vice versa.

15. Rotors & Reflector First rotor rotates each time a character is input. The second rotor rotates once each time the first rotor makes one full turn. The third rotor rotates once each time the second rotor has rotated completely.

16. Light Bulb Panel

17. How it works? Light Panel Keyboard Reflector Left Rotor Middle Rotor Right Rotor Entry Drum Q W E R T Z I O U Y X C V B M L N S D F G K J Q W E R T Z I O Q W E R T Z I U S D F G K J S D F G P Y X C V B M L P Y X C V B M L N P N K J O O M F Plugboard P A + - + M O - BATTERY H A O N J X B F J B P O N X M M A A U H H H  Copyright © 2016 CipherMachines.com and EnigmaMuseum.com

18. Enigma rotor and reflector table They pick any three rotors and one reflector out of these on daily basis.These are the initial configuration of those rotors and reflectors.

19. How many possible keys are there when you swap each letter of the alphabet with another letter? 26*25*24*23*22*21*20*19*18*17*16*15*14*13*12*11*10*9*8*7*6*5*4*3*2*1 =26! = 400 000 000 000 000 000 000 000 000 FACTS:

20. 400 septillion keys! 6.5 billion people in the world 31 million seconds in a year If everyone in the world checked one key per second, it would still take 2 billion years to check them all!

21. THANKYOU!