def key_from_keyfile(keyfile):
    """
    This method reads in the bytes in the keyfile and returns the
    SHA256 as the key.
    
    :param keyfile: The path to a key file or a file-like object.
    """
    if hasattr(keyfile, 'read'):
        buf = keyfile.read()
    else:
        # Assume it is a filename and open it to read contents.
        with open(keyfile, 'rb') as fp:
            buf = fp.read()
            
    sha = SHA256.new()
    if len(buf) == 33:
        sha.update(buf)
        return sha.digest()
    elif len(buf) == 65:
        sha.update(struct.unpack('<65s', buf)[0].decode())
        return sha.digest()
    else:
        # This chunked updating of the sha is probably not really necessary
        while buf:
            if len(buf) <= 2049:
                sha.update(buf)
                buf = ''
            else:
                sha.update(buf[:2048])
                buf = buf[2048:]
        return sha.digest()