Google Chrome - Alphanumeric hashes to identify extensions

Question

Google Chrome is using alpha numeric hashes as identifiers for the Chrome extensions. For eg. \"ajpgkpeckebdhofmmjfgcjjiiejpodla\" is the identifier for XMarks Bookmark Sync

Answer 1

Chromium generates the id via public key. If you use the extension gallery, they handle all that for you.

From the source:

bool Extension::GenerateId(const std::string& input, std::string* output) {
  CHECK(output);
  if (input.length() == 0)
    return false;

  const uint8* ubuf = reinterpret_cast(input.data());
  SHA256Context ctx;
  SHA256_Begin(&ctx);
  SHA256_Update(&ctx, ubuf, input.length());
  uint8 hash[Extension::kIdSize];
  SHA256_End(&ctx, hash, NULL, sizeof(hash));
  *output = StringToLowerASCII(HexEncode(hash, sizeof(hash)));
  ConvertHexadecimalToIDAlphabet(output);

  return true;
}

Take a look at extension.cc file it has more detailed information such as generating the .pem file exncoding/decoding, etc.