huge commit

2026/cscg/crypto/punkhash/generate.py

@@ -0,0 +1,34 @@
+#!/usr/bin/env python3
+
+import json
+import random
+
+from Crypto.Cipher import AES
+from Crypto.Util.number import getPrime
+from Crypto.Util.Padding import pad
+
+FLAG = "dach2026{xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx}"
+
+pbits = 137
+p = getPrime(pbits)
+key_bits = 16
+
+# Generate hash of the key
+factors = [random.SystemRandom().randint(0, p-1) for _ in range(key_bits)]
+preimage = [random.SystemRandom().randint(0, 0xff) for _ in range(key_bits)]
+hash = sum([factors[i] * preimage[i] % p for i in range(key_bits)]) % p
+
+# Encrypt flag
+key = bytes(preimage)
+cipher = AES.new(key, AES.MODE_ECB)
+enc = cipher.encrypt(pad(FLAG.encode(), 16)).hex()
+
+data = {
+    "p": p,
+    "factors": factors,
+    "hash": hash,
+    "enc_flag": enc
+}
+
+with open("data.json", "w") as f:
+    json.dump(data, f, indent=4)