Seeing as how defining what is, or isn't, part of the mbox specification has become a rather critical aspect to this discussion I've been trying to find out more about this. So far I haven't been finding as much as I had hoped. Seems that it's more of a common format that came out of RFC-822 rather than something hard coded on it's own.
Found a variety of links to a man page on this subject. Here's one... http://www.qmail.org/qmail-manual-html/man5/mbox.html An article on About.com concerning it... http://email.about.com/library/weekly/aa111300a.htm Same site, this time a reference to a conversion tool to go from Eudora to a Unix mbox format... http://email.about.com/library/daily/bl_dd090500.htm An article about a security bug in Eudora dealing with attachments. I've included this as it has a really good description of what it actually does. And things to avoid. http://www.securiteam.com/securitynews/5EP0A2K41S.html Since IMAP was brought up as a concern, found the following article on how Eudora deals with attachments in this kind of setup. Not too far off from what I was guessing. http://www.umanitoba.ca/campus/acn/support/imap/eudora.html The S/MIME question is a bit fuzzier. Eudora apparently supports PGP natively, and S/MIME via a 3rd party plugin. The mechanics of how this works is rather sketchy. Here's an article covering this. http://www.worldtalk.com/Products/SMIME%20Everywhere/sme.shtm I believe that addresses most of the questions posed. I'd still like to find a more definitive reference to mbox than the rather brief man page I linked to above. Mainly I would like to find out if linking to an attachment rather than storing it encoded is actually breaking the spec. It seems that mbox is open to some pretty wide interpretation depending on how you wish to implement it. Later on, -- "Outside of a dog, a book is man's best friend. Inside of a dog, it's too dark to read." - Groucho Marx
