commit 37ae77acbf1a07cfac024f616143c6dea87b7073
Author: James Hilliard <james.hilliard1@gmail.com>
Date:   Sat May 6 11:45:24 2017 -0500

diff --git a/gwdecrypt.py b/gwdecrypt.py
new file mode 100644
index 0000000..7fc47ee
--- /dev/null
+++ b/gwdecrypt.py
@@ -0,0 +1,58 @@
+#!/usr/bin/env python3
+# W.J. van der Laan 2017, distributed under MIT license
+# James Hilliard 2017
+import binascii
+import base64
+import struct
+import json
+import os, sys
+import hashlib
+from Crypto import Random
+from Crypto.Cipher import AES
+
+KEY = binascii.a2b_hex(b'fffffbffeffffbfffbbfffbfdbfff7ffffffffffffffdfffff7fffffbfffffff')
+
+def unpad(s):
+    '''PKCS7 unpad.'''
+    padlen = s[len(s)-1]
+    if padlen > 16:
+        raise ValueError('Invalid padding')
+    return s[:-padlen]
+
+def decrypt(data_in):
+    # first 32 bytes are IV, we only need 16 of that
+    iv = data_in[0:16]
+    cipher = AES.new(KEY, AES.MODE_CBC, iv)
+    data_out = cipher.decrypt(data_in[32:])
+    data_out = unpad(data_out)
+
+    crc = data_out[0:4]
+    ccrc = struct.pack('I',binascii.crc32(data_out[4:]))
+    assert(crc == ccrc)
+    json_data = json.loads(data_out[4:].decode())
+    return json_data
+
+def main():
+    if len(sys.argv) < 2:
+        print('Usage: %s /path/to/configfile.bin' % os.path.basename(sys.argv[0]))
+        exit(1)
+    with open(sys.argv[1], 'rb') as f:
+        data_in = base64.b64decode(f.read())
+
+    # decode second layer, create one huge JSON file with record types at top level
+    json_data = decrypt(data_in)
+    out_recs = {}
+    for record in json_data:
+        
+        d = base64.b64decode(record['data'])
+        assert(record['type'] not in out_recs) # duplicate
+        out_recs[record['type']] = decrypt(d)
+
+    if len(sys.argv) == 3:
+        with open(sys.argv[2], 'w') as outfile:
+            json.dump(out_recs, outfile, indent=4, separators=(',', ': '))
+    else:
+        json.dump(out_recs, sys.stdout, indent=4, separators=(',', ': '))
+
+if __name__ == '__main__':
+    main()
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