cyber-security-resources/crypto/challenges/04_Classic_Vigenere_Cipher.md
2023-08-15 09:52:53 -04:00

1.8 KiB

Certainly! Here are three additional cryptographic challenges suitable for your class, ranging in difficulty:

Challenge 4: Classic Vigenère Cipher

Level: Beginner

Description: Crack a message encrypted using the Vigenère cipher with a known keyword.

Challenge Text:

Encrypted Message: "XBGXLTVJZTFKTRDCXWPNCRTGDHDDJQKFTZR"
Keyword: "KEYWORD"

Instructions:

  1. Utilize the given keyword to decrypt the Vigenère cipher.
  2. Provide the original plaintext.

Challenge 5: Implement Diffie-Hellman Key Exchange

Level: Intermediate

Description: Simulate the Diffie-Hellman key exchange algorithm to securely share a symmetric key between two parties.

Challenge Text:

Given prime p = 23, base g = 5
Party A's private key: 6
Party B's private key: 15

Instructions:

  1. Compute Party A's and Party B's public keys.
  2. Compute the shared secret key for both parties.
  3. Validate that both parties have the same shared secret key.

Challenge 6: Digital Signature Forgery

Level: Advanced

Description: Provide a digital signature scheme with a weakness (e.g., using a small prime number). Challenge the students to forge a digital signature for a new message.

Challenge Text:

Signature scheme: RSA with n = 391, e = 3, d = 107
Signed message: ("HELLO", signature = 220)
Challenge: Forge a signature for the message "WORLD"

Instructions:

  1. Understand the weakness in the provided RSA signature scheme.
  2. Forge a signature for the new message.
  3. Validate the forged signature.

Note: Make sure to clarify the educational purpose of the challenges and emphasize the importance of ethical behavior and responsible use of these skills. Providing a controlled environment or sandbox for practicing these challenges will ensure that students can learn without violating any legal or ethical guidelines.