@classmethod
def from_description(cls, description, default_key_length=None):
    """Load key info from key info description.

        :param str description: Key info description
        :param int default_key_length: Key length to use if not found in description
        """
    description_parts = description.split('/', 1)
    algorithm = description_parts[0]
    try:
        key_length = int(description_parts[1])
    except IndexError:
        if default_key_length is None:
            raise ValueError(
                'Description "{}" does not contain key length and no default key length is provided'
                .format(description))
        key_length = default_key_length
    return cls(description, algorithm, key_length)
