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Web Tools for Classical Cryptology

Web Tools for Classical Cryptology. Tristan Beeble. Overview. Background Types of problems Tools. Cryptology. Cryptography Encoding a message Cryptoanalysis Decoding a message. Background. Client: Professor Lesh Gen-ed Math course Help solve homework problems. Goals. Decoding

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Web Tools for Classical Cryptology

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  1. Web Tools for Classical Cryptology Tristan Beeble

  2. Overview • Background • Types of problems • Tools

  3. Cryptology • Cryptography • Encoding a message • Cryptoanalysis • Decoding a message

  4. Background • Client: Professor Lesh • Gen-ed Math course • Help solve homework problems

  5. Goals • Decoding • Additional study • Aid, not solve • Easy to use

  6. Terms • Plaintext: Message you want to send • Ciphertext: Actual text sent • Key: What’s needed to decode • Algorithm: How to decode • Cipher: allowed plaintexts, keyspace, encryption and decryption algorithm

  7. Types of Ciphers • Caesar Cipher • Monoalphabetic Ciphers • Polyalphabetic Ciphers • Vigenère Cipher

  8. Caesar Cipher Plaintext: tristan Key: 7 Ciphertext: aypzahu

  9. Monoalphabetic Cipher Caesar Plaintext: A B C D E Ciphertext: B C D E F Monoalphabetic Plaintext: A B C D E Ciphertext: E C A B D

  10. Monoalphabetic cipher

  11. Polyalphabetic Cipher • Vigenère cipher Plaintext: i n i t i a t e Key: u n i o n u n i

  12. Vigenère cipher

  13. Vigenère Cipher Plaintext: i n i t i a t e Key: u n i o n u n i Ciphertext: c a q h v u g m

  14. Caesar Cipher Decryption • Same idea as Encryption • Backwards Ciphertext: aypzahu Key: 7(-7) Plaintext: tristan

  15. Caesar Cipher Tool

  16. Caesar Cipher Tool

  17. Monoalphabetic Cipher Decryption • First Step:Guess work • Word length • Partial solutions • Second Step:Frequency Analysis

  18. Frequency analysis

  19. Frequency Analysis Tool

  20. Monoalphabetic Cipher Tool lmstn qtomq ***e* te**t e t

  21. Vigenère Cipher Decryption • Repeated Segments • Factors • Plaintext: the bird ate the cat • Key: uni onun ion uni onu • Cipher: num pvlq ihr num qnn 10 • Multiple Frequency Analysis

  22. Vigenère Cipher Tools fgsjetladkjdjkeifldlkowfgewsloiodkjplkjhgfetllk DJK 21

  23. Repeated Substrings THBZTHBT T 1 0 0 0 1 0 0 1 H 0 2 0 0 0 2 0 0 B 0 0 3 0 0 0 3 0 Z 0 0 0 4 0 0 0 0 T 1 0 0 0 5 0 0 1 H 0 2 0 0 0 6 0 0 B 0 0 3 0 0 0 7 0 T 1 0 0 0 1 0 0 8 Repeated substring started Repeated substring ended

  24. Vigenère Cipher Tools

  25. Future work • Encryption • More types of Ciphers

  26. Accomplishments • Save the student time • Allow them to do more • Easier for the professor • More complex examples

  27. Questions?

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