In 1976, W. Diffie and M. E. Hellman created a key exchange protocol [1][2]. Alice and Bob will use it to exchange a secret key on a communication channel without authentification, then Alice will send a code encrypted by a xor [3] with the secret key. A few information about the sniffer below : it intercepts messages between the two protagonists. Each message has a header (source, receiver, date) which is not alterable, and data delimited by quotes that can be edited.
You'll use the following URL and the plaintext code to get the flag to solve this challenge :
solution_diffie_hellman.php?password=plaintext_code |
