init htb

old htb folders

HTB/challenges/crypto/BabyEncryption/ape.py

@@ -0,0 +1,27 @@
+import string
+
+
+def encryption(msg):
+    ct = []
+    for char in msg:
+        ct.append((123 * ord(char) + 18) % 256)
+    return bytes(ct)
+
+dict = {}
+
+for elem in string.printable:
+    enc = encryption(elem)[0]
+    dict[elem] = enc
+    dict[enc] = elem
+
+print(dict)
+
+f = open('./msg.enc','r')
+ct = f.readline()
+ct = [int(ct[i:i+2],16) for i in range(0, len(ct), 2)]
+
+solve = ""
+for elem in ct:
+    solve += dict[elem]
+
+print(solve)

HTB/challenges/crypto/BabyEncryption/chall.py

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+import string
+from secret import MSG
+
+def encryption(msg):
+    ct = []
+    for char in msg:
+        ct.append((123 * char + 18) % 256)
+    return bytes(ct)
+
+ct = encryption(MSG)
+f = open('./msg.enc','w')
+f.write(ct.hex())
+f.close()
+
+

HTB/challenges/crypto/BabyEncryption/msg.enc

@@ -0,0 +1 @@
+6e0a9372ec49a3f6930ed8723f9df6f6720ed8d89dc4937222ec7214d89d1e0e352ce0aa6ec82bf622227bb70e7fb7352249b7d893c493d8539dec8fb7935d490e7f9d22ec89b7a322ec8fd80e7f8921

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

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+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")

HTB/challenges/crypto/The Last Dance/crypto_the_last_dance/out.txt

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+c4a66edfe80227b4fa24d431
+7aa34395a258f5893e3db1822139b8c1f04cfab9d757b9b9cca57e1df33d093f07c7f06e06bb6293676f9060a838ea138b6bc9f20b08afeb73120506e2ce7b9b9dcd9e4a421584cfaba2481132dfbdf4216e98e3facec9ba199ca3a97641e9ca9782868d0222a1d7c0d3119b867edaf2e72e2a6f7d344df39a14edc39cb6f960944ddac2aaef324827c36cba67dcb76b22119b43881a3f1262752990
+7d8273ceb459e4d4386df4e32e1aecc1aa7aaafda50cb982f6c62623cf6b29693d86b15457aa76ac7e2eef6cf814ae3a8d39c7

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

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+from Crypto.Cipher import ChaCha20
+from secret import FLAG
+import os
+
+
+def encryptMessage(message, key, nonce):
+    cipher = ChaCha20.new(key=key, nonce=iv)
+    ciphertext = cipher.encrypt(message)
+    return ciphertext
+
+
+def writeData(data):
+    with open("out.txt", "w") as f:
+        f.write(data)
+
+
+if __name__ == "__main__":
+    message = b"Our counter agencies have intercepted your messages and a lot "
+    message += b"of your agent's identities have been exposed. In a matter of "
+    message += b"days all of them will be captured"
+
+    key, iv = os.urandom(32), os.urandom(12)
+
+    encrypted_message = encryptMessage(message, key, iv)
+    encrypted_flag = encryptMessage(FLAG, key, iv)
+
+    data = iv.hex() + "\n" + encrypted_message.hex() + "\n" + encrypted_flag.hex()
+    writeData(data)