[BCP179]   Best Current Practice 179,
              <https://www.rfc-editor.org/info/bcp179>.
              At the time of writing, this BCP comprises the following:

              Hornquist Astrand, L. and T. Yu, "Deprecate DES, RC4-HMAC-
              EXP, and Other Weak Cryptographic Algorithms in Kerberos",
              BCP 179, RFC 6649, DOI 10.17487/RFC6649, July 2012,
              <https://www.rfc-editor.org/info/rfc6649>.