Un simple oracle [1/2]

Category: Cryptanalysis - Points: 981 - Difficulty: Easy - Solves: 150

Description:

Bonjour agent, Nous avons découvert un étrange service ouvert sur un des serveurs de Hallebarde. Il semble possible d'interagir avec lui. Pourrriez-vous récupérer son secret?

nc challenge.404ctf.fr 32128

Solution:

This cryptanalysis challenge is solved using a basic RSA attack: the Chosen Plaintext Attack. To do this, I used a tool called RSHack and I simply entered the public key parameters and sent a request to the oracle to calculate, with the help of the tool, the ciphertext-plaintext relation and thus decrypt the message.

🚩 FLAG

404CTF{L3s_0r4cl3s_RSA_s0n7_si_fr4g1l35}