ALL the CTFS of Crypto2025 finally

crypto-hash/equality/attack.py

@@ -0,0 +1,17 @@
+#!/usr/bin/env python3
+from pwn import *
+HOST = "130.192.5.212"
+PORT = 6631
+#Generate with MD4-Collision
+m1 = "c2a66ef939681a46895edbd696dec463691253412c051f4c147b955348bcb90d9721b08e22ee254c42f24fa7d6a946ca16a09caa7e71cc430c30f1448763b200"
+m2 = "c2a66ef939681ac6895edb4696dec463691253412c051f4c147b955348bcb90d9721b08e22ee254c42f24fa7d6a946ca16a09baa7e71cc430c30f1448763b200"
+server = remote(HOST,PORT)
+server.send(m1)
+server.send(b'\n')
+server.send(m2)
+server.send(b'\n')
+
+print(server.recv(1024))
+
+print(server.recv(1024))
+

crypto-hash/equality/chall.py

@@ -0,0 +1,27 @@
+from Crypto.Hash import MD4
+import hashlib
+from binascii import unhexlify
+from secret import flag
+
+
+def md4(data: bytes) -> str:
+    h = MD4.new()
+    h.update(data)
+    return h.hexdigest()
+
+
+print("Find two strings that are both equal and different! I'll use _optimized algorithms_ to check.")
+
+s1 = unhexlify(input("Enter the first string: "))
+s2 = unhexlify(input("Enter your second string: "))
+
+md4_s1 = md4(s1)
+md4_s2 = md4(s2)
+
+md5_s1 = hashlib.md5(s1).hexdigest()
+md5_s2 = hashlib.md5(s2).hexdigest()
+
+if md4_s1 == md4_s2 and md5_s1 != md5_s2:
+    print(f"Good job! {flag}")
+else:
+    print("Try again!")