rc/mime/crypto

   1 .cer    application/pkix-cert
   2 .crl    application/pkix-crl
   3 .gpg    application/pgp-encrypted
   4 .p10    application/pkcs10
   5 .p12    application/pkcs12
   6 .p7c    application/pkcs7-mime
   7 .p7m    application/pkcs7-mime
   8 .p7s    application/pkcs7-signature
   9 .p8     application/pkcs8
  10 .p8e    application/pkcs8-encrypted
  11 .pem    application/x-pem-file
  12 .pfx    application/pkcs12
  13 .sig    application/pgp-signature