Assignment 4

Due on 28/03/2023

Problem(s)

Part-1:

1. Write a menu-driven program to encrypt/decrypt byte-string data with the following options:

• User should be able to choose any of the following six algorithms:
  • Caesar Cipher
  • Vegenare Cipher (for alphanumeric data)
  • Vernam Cipher (using XOR)
  • One Time Pad (OTP) (using LCG for appropriate case)
  • XOR with ECB-mode (with appropriate padding)
  • XOR with CBC-mode (with appropriate padding)
• Accept/generate the appropriate Key as per the selected algorithm
• Do proper error handling as well. (e.g., for incorrect key length)
• Main-Menu must include the following options:
  • Encrypt Message
  • Decrypt Message
  • Quit

Part-2:

1. Write a menu-driven program with the following additional features along with the features provided in previous questions:

• The program should also be able to encrypt/decrypt the data-files. (e.g., for a given message.txt, you could get the corresponding secret.enc as the encrypted file, and vice-versa)
• The program must take the file name of the encrypted/decrypted file as input before saving
• Encrypted data-file must have the extension .enc (e.g., encrypted.enc)
• Main-Menu must include the following options:
  • Encrypt Message
  • Encrypt File
  • Decrypt Message
  • Decrypt File
  • Quit
• Program MUST offer all the utilities as given in Part-1 of this assignment

* Remember, the user may not input the byte string, so you must do proper encoding to get the byte-string from the input.

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