itsdangerous.py 文件源码

def derive_key(self):
        """This method is called to derive the key.  If you're unhappy with
        the default key derivation choices you can override them here.
        Keep in mind that the key derivation in itsdangerous is not intended
        to be used as a security method to make a complex key out of a short
        password.  Instead you should use large random secret keys.
        """
        salt = want_bytes(self.salt)
        if self.key_derivation == 'concat':
            return self.digest_method(salt + self.secret_key).digest()
        elif self.key_derivation == 'django-concat':
            return self.digest_method(salt + b'signer' +
                self.secret_key).digest()
        elif self.key_derivation == 'hmac':
            mac = hmac.new(self.secret_key, digestmod=self.digest_method)
            mac.update(salt)
            return mac.digest()
        elif self.key_derivation == 'none':
            return self.secret_key
        else:
            raise TypeError('Unknown key derivation method')