'Validates LTI signature and returns LTI parameters'

@classmethod
def get_validated_lti_params(cls, strategy):

    request = Request(uri=strategy.request.build_absolute_uri(), http_method=strategy.request.method, body=strategy.request.body)
    try:
        lti_consumer_key = request.oauth_consumer_key
    except AttributeError:
        return None
    (lti_consumer_valid, lti_consumer_secret, lti_max_timestamp_age) = cls.load_lti_consumer(lti_consumer_key)
    current_time = calendar.timegm(time.gmtime())
    return cls._get_validated_lti_params_from_values(request=request, current_time=current_time, lti_consumer_valid=lti_consumer_valid, lti_consumer_secret=lti_consumer_secret, lti_max_timestamp_age=lti_max_timestamp_age)
