1 files changed, 92 insertions, 0 deletions
diff --git a/tools/crx_id/crx_id.py b/tools/crx_id/crx_id.py
new file mode 100755
index 0000000..6350068
--- /dev/null
+++ b/tools/crx_id/crx_id.py
@@ -0,0 +1,92 @@
+#!/usr/bin/python
+# Copyright (c) 2011 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+""" Read a CRX file and write out the App ID and the Full Hash of the ID.
+See: http://code.google.com/chrome/extensions/crx.html
+and 'http://stackoverflow.com/questions/'
+  + '1882981/google-chrome-alphanumeric-hashes-to-identify-extensions'
+for docs on the format.
+"""
+
+import sys
+import hashlib
+
+def usage(argv):
+  print "%s: crx_file" % argv[0]
+
+EXPECTED_CRX_MAGIC_NUM = 'Cr24'
+EXPECTED_CRX_VERSION = 2
+
+def HexToInt(hex_chars):
+  """ Convert bytes like \xab -> 171 """
+  val = 0
+  for i in xrange(len(hex_chars)):
+    val += pow(256, i) * ord(hex_chars[i])
+  return val
+
+def HexToMPDecimal(hex_chars):
+  """ Convert bytes to an MPDecimal string. Example \x00 -> "aa"
+      This gives us the AppID for a chrome extension.
+  """
+  result = ''
+  base = ord('a')
+  for i in xrange(len(hex_chars)):
+    value = ord(hex_chars[i])
+    dig1 = value / 16
+    dig2 = value % 16
+    result += chr(dig1 + base)
+    result += chr(dig2 + base)
+  return result
+
+def HexTo256(hex_chars):
+  """ Convert bytes to pairs of hex digits. E.g., \x00\x11 -> "{0x00, 0x11}"
+      The format is taylored for copy and paste into C code:
+      const uint8 sha256_hash[] = { ... }; """
+  result = []
+  for i in xrange(len(hex_chars)):
+    value = ord(hex_chars[i])
+    dig1 = value / 16
+    dig2 = value % 16
+    result.append('0x' + hex(dig1)[2:] + hex(dig2)[2:])
+  return '{%s}' % ', '.join(result)
+
+def GetPublicKey(f):
+  magic_num = f.read(4)
+  if magic_num != EXPECTED_CRX_MAGIC_NUM:
+    raise 'Invalid magic number: %s (expecting %s)' % (magic_num,
+                                                       EXPECTED_CRX_MAGIC_NUM)
+  version = f.read(4)
+  if not version[0] != EXPECTED_CRX_VERSION:
+    raise 'Invalid version number: %s (expecting %s)' % (version,
+                                                         EXPECTED_CRX_VERSION)
+  pub_key_len_bytes = HexToInt(f.read(4))
+  sig_len_bytes = HexToInt(f.read(4))
+  pub_key = f.read(pub_key_len_bytes)
+  return pub_key
+
+def GetCRXHash(filename):
+  f = open(filename, 'rb')
+  pub_key = GetPublicKey(f)
+  f.close()
+  pub_key_hash = hashlib.sha256(pub_key).digest()
+  return HexTo256(pub_key_hash)
+
+def GetCRXAppID(filename):
+  f = open(filename, 'rb')
+  pub_key = GetPublicKey(f)
+  f.close()
+  pub_key_hash = hashlib.sha256(pub_key).digest()
+  # AppID is the MPDecimal of only the first 128 bits of the hash.
+  return HexToMPDecimal(pub_key_hash[:128/8])
+
+def main(argv):
+  if len(argv) != 2:
+    usage(argv)
+    return 1
+  print 'Raw Bytes: %s' % GetCRXHash(sys.argv[1])
+  print 'AppID: %s' % GetCRXAppID(sys.argv[1])
+
+if __name__ == '__main__':
+  sys.exit(main(sys.argv))