[STD70]    Internet Standard 70,
              <https://www.rfc-editor.org/info/std70>.
              At the time of writing, this STD comprises the following:

              Housley, R., "Cryptographic Message Syntax (CMS)", STD 70,
              RFC 5652, DOI 10.17487/RFC5652, September 2009,
              <https://www.rfc-editor.org/info/rfc5652>.