init htb

old htb folders

HTB/challenges/crypto/The Last Dance/crypto_the_last_dance/ape.py

@@ -0,0 +1,31 @@
+import os
+from Crypto.Cipher import ChaCha20
+
+def encrypt_message(message, key, nonce):
+    cipher = ChaCha20.new(key=key, nonce=nonce)
+    ciphertext = cipher.encrypt(message)
+    return ciphertext
+
+def chosen_plaintext_attack(ciphertext, key, nonce):
+    # Create a dictionary of known plaintexts and their corresponding ciphertexts
+    known_plaintexts = {b"Our counter agencies have": b"", b"example2": b""}
+    for plaintext in known_plaintexts:
+        # Encrypt the known plaintext using the same key and nonce as the original ciphertext
+        known_ciphertext = encrypt_message(plaintext, key, nonce)
+        # Compare the known ciphertext with the original ciphertext
+        if known_ciphertext == ciphertext:
+            # If the ciphertexts match, the original plaintext is likely the known plaintext
+            return plaintext
+    return None
+
+if __name__ == "__main__":
+    message = b"Our counter agencies have intercepted your messages and a lot"
+    key, nonce = os.urandom(32), os.urandom(12)
+    encrypted_message = encrypt_message(message, key, nonce)
+
+    # Perform the chosen plaintext attack
+    recovered_message = chosen_plaintext_attack(encrypted_message, key, nonce)
+    if recovered_message is not None:
+        print("Recovered message:", recovered_message)
+    else:
+        print("Failed to recover message")