@Override
    public void updateDiskCacheKey(MessageDigest messageDigest) throws UnsupportedEncodingException {
        messageDigest.update(id.getBytes(STRING_CHARSET_NAME));
        signature.updateDiskCacheKey(messageDigest);
    }
A class for keeping track of the cache key of the original data + any requested signature.
core/src/main/java/com/bumptech/glide/load/engine/OriginalKey.java