// both are illegal.
		return "", false, errMalformedDomain
	}

	domain, isASCII := ascii.ToLower(domain)
	if !isASCII {
		// Received non-ASCII domain, e.g. "perché.com" instead of "xn--perch-fsa.com"
		return "", false, errMalformedDomain
	}

	if domain[len(domain)-1] == '.' {
		// We received stuff like "Domain=www.example.com.".
		// Browsers do handle such stuff (actually differently) but