From 8c617b721f2fec1fef53ed0d02b84195069f1065 Mon Sep 17 00:00:00 2001
From: KnugiHK <24708955+KnugiHK@users.noreply.github.com>
Date: Sun, 3 Dec 2023 13:49:57 +0800
Subject: [PATCH] Create bruteforce_crypt15.py

---
 scripts/bruteforce_crypt15.py | 48 +++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)
 create mode 100644 scripts/bruteforce_crypt15.py

diff --git a/scripts/bruteforce_crypt15.py b/scripts/bruteforce_crypt15.py
new file mode 100644
index 0000000..56cf912
--- /dev/null
+++ b/scripts/bruteforce_crypt15.py
@@ -0,0 +1,48 @@
+import hmac
+import javaobj
+import zlib
+from Crypto.Cipher import AES
+from hashlib import sha256
+
+
+def _generate_hmac_of_hmac(key_stream):
+    key = hmac.new(
+        hmac.new(
+            b'\x00' * 32,
+            key_stream,
+            sha256
+        ).digest(),
+        b"backup encryption\x01",
+        sha256
+    )
+    return key.digest(), key_stream
+
+
+def _extract_encrypted_key(keyfile):
+    key_stream = b""
+    for byte in javaobj.loads(keyfile):
+        key_stream += byte.to_bytes(1, "big", signed=True)
+
+    return _generate_hmac_of_hmac(key_stream)
+
+
+key = open("encrypted_backup.key", "rb").read()
+database = open("wa.db.crypt15", "rb").read()
+main_key, hex_key = _extract_encrypted_key(key)
+for i in range(100):
+    iv = database[i:i+16]
+    for j in range(100):
+        cipher = AES.new(main_key, AES.MODE_GCM, iv)
+        db_ciphertext = database[j:]
+        db_compressed = cipher.decrypt(db_ciphertext)
+        try:
+            db = zlib.decompress(db_compressed)
+        except zlib.error:
+            ...
+        else:
+            if db[0:6] == b"SQLite":
+                print(f"Found!\nIV: {i}\nOffset: {j}")
+                print(db_compressed[:10])
+                exit()
+
+print("Not found! Try to increase maximum search.")