apparently-from
apparently-to
application
+application/pgp-encrypted
+application/pgp-signature
+application/pkcs7-signature
+application/x-pkcs7-signature
audio
base64
bcc
content-type
copiousoutput
date
+delivery-status
digest
edit
+encrypted
+enriched
+enveloped-data
expires
external-body
followup-to
image
in-reply-to
iso-2022-jp
+keys-only
lines
list-post
mail-followup-to
mime-version
model
multipart
+multipart/mixed
nametemplate
needsterminal
news
newsgroups
+octet-stream
organization
+pgp
+pgp-encrypt
+pgp-keys
+pgp-sign
+pgp-signed
+pkcs7-mime
+plain
print
quoted-printable
received
reply-to
return-path
rfc822
+rfc822-headers
sender
+sign
+signclear
+signed
+signed-data
status
subject
supercedes
x-comment-to
x-convert
x-label
+x-pgp-message
+x-pkcs7-mime
xref
x-status
x-uuencode