Loading presentation...

Present Remotely

Send the link below via email or IM


Present to your audience

Start remote presentation

  • Invited audience members will follow you as you navigate and present
  • People invited to a presentation do not need a Prezi account
  • This link expires 10 minutes after you close the presentation
  • A maximum of 30 users can follow your presentation
  • Learn more about this feature in our knowledge base article

Do you really want to delete this prezi?

Neither you, nor the coeditors you shared it with will be able to recover it again.


Cryptography Midterm Presentation 2011

My midterm presentation for MAT 3510 on my implementation of Vigenere ciphers and Vigenere cipher breaking techniques in Java. Note: still working on it.

Shawn Waldon

on 28 February 2011

Comments (0)

Please log in to add your comment.

Report abuse

Transcript of Cryptography Midterm Presentation 2011

Vigenere Ciphers
and Breaking Techniques
in Java Shawn Waldon A Shortcut for Encrypting Vigenere Ciphers Due to the nature of the Vigenere square, the row of the plaintext letter and the column of the keyword letter
will always contain the letter
(plainletter + keyletter) mod 26 Applications of the Shortcut in Decrypting
Vigenere Ciphers The shortcut means that when decrypting, the keyword letter can be subtracted from the ciphertext letter mod 26 to find the plaintext letter.
This avoids a loop to find the right space in the Vigenere Square. This is tedious: Plotting Signatures and Scrawls Creating the line graphs is mainly a challenge because the maximum value being graphed varies
Scaling the graph based on the maximum value being graphed is tricky. And it has to work no matter where the maximum value is: Demo ! Questions? An Alternate Form of Vigenere Cipher The encipher and decipher modes of the program also allow using a Vigenere Autokey Cipher I also added a variation of my own here: an 'autokeyword' cipher, which is like an autokey cipher, but with a variable length keyword. So Which type is most secure? With an autokey cipher, the cryptanalyst only has to try 26 different letters for the key
Friedman and Kasiski made solving a Vigenere keyword cipher easier, and modern computers/graphics make them easy to break.
From the several hours of research I did, I can't tell if anyone has even tried my autokeyword cipher idea, and my inclination is that it is more secure than the other two
Full transcript