Generate a HMAC security hash from the provided info.

def generate_security_hash(self, content_type, object_pk, timestamp):
        """
        Generate a HMAC security hash from the provided info.
        """
        info = (content_type, object_pk, timestamp)
        key_salt = "django.contrib.forms.CommentSecurityForm"
        value = "-".join(info)
        return salted_hmac(key_salt, value).hexdigest()