public void SetExtensions(
            X509Extensions extensions)
        {
            this.extensions = extensions;

            if (extensions != null)
            {
                X509Extension altName = extensions.GetExtension(X509Extensions.SubjectAlternativeName);

                if (altName != null && altName.IsCritical)
                {
                    altNamePresentAndCritical = true;
                }
            }
        }