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Vigenere Cipher

The rate and impact of security breaches in recent years makes it imperative that developers understand the methods bad actors use to compromise apps. Understanding how an app can be compromised is the first step in coming up with effective protection measures.

One of the easiest ways bad actors can compromise an app is to access data that's left unencrypted by the developer. There are a number of strong encryption algorithms available to ensure that data is not readable even if access is compromised. These include AES, Blowfish, and TripleDES to name a few.

However, these algorithms can be quite complex to implement so the objective of this app is to implement a classical encryption algorithm, the Vigenere Cipher to learn the basics of how ciphers work.

Requirements & Constraints

  • Developers should use only native language features to implement the Vigenere Cipher. Libraries are not allowed.
  • Developers should design and implement their own solution using only the description of the steps in the Vigenere Cipher algorithm.
  • After successfully implementing this algorithm Developer should ask themselves these questions: - Would you feel confident encrypting your financial information using the Vigenere Cipher? Why? - How would you detect that a message had been encrypted using the Vigenere Cipher? - How would you go about trying to crack this encryption?

User Stories

  • User can see the app window with these components:
    • Plain text message input field
    • Encryption key input field
    • Action buttons - 'Encrypt' and 'Decrypt'
    • Resulting encrypted or decrypted message
  • User can enter the text to be encrypted in the plain text message input field
  • User can enter the Encryption key the Vigenere algorithm will use to encrypt the plain text message.
  • User can click see see the 'Decrypt' button disabled until the plain text has been encrypted.
  • User can click the 'Encrypt' button to encrypt the plain text message
  • User can see the encrypted message displayed in the result field.
  • User can see the 'Decrypt' button enabled after the encrypted message has been displayed.
  • User can click the 'Decrypt' button to decrypt the encrypted message and to display its contents in the result field.

Bonus features

  • User can see a 'Compare' button after decryption that compares the original plain text message with the decrypted message
  • User can see an error message if the 'Compare' detects differences in the contents of these two fields.

Example projects

Vigenere Encryption