py_ecdsa.py 文件源码

def prepare_key(self, key):

        if isinstance(key, ecdsa.SigningKey) or \
           isinstance(key, ecdsa.VerifyingKey):
            return key

        if isinstance(key, string_types):
            if isinstance(key, text_type):
                key = key.encode('utf-8')

            # Attempt to load key. We don't know if it's
            # a Signing Key or a Verifying Key, so we try
            # the Verifying Key first.
            try:
                key = ecdsa.VerifyingKey.from_pem(key)
            except ecdsa.der.UnexpectedDER:
                key = ecdsa.SigningKey.from_pem(key)

        else:
            raise TypeError('Expecting a PEM-formatted key.')

        return key