What is needed for S/MIME remailer ?
The other day I was wondering what it would take to make an anonymous remailer for an S/MIME client. Implementing S/MIME from scratch is a lot of work given the lack of a public domain implementation, but it seems that a remailer could be built on top of a commercial email product that supported S/MIME. The question is: What features should a commercial S/MIME email product have to make it easy to support a remailer? Are there a small set of command line options that would greatly simplify a remailer implementation? --Bob Baldwin
My understanding of S/MIME isn't excellent, so I figure there are things I could be confused about which may make this a bit wrong.. I figure a command line S/MIME program which could easily be integrated into a remailer wouldhave the following features: A) limit on number of multiple concurrent procersses doing decryption. Remailer spams have the bad effect of spwaning hundreds of concurrent PGPs on the mailhost, bringing things to halt. Limiting number of concurrent decryptions would help this problem. B) A strong interaction with the UNIX shell, with the program returning a return code based on whether or not the decryption succeeded. (Remailers only do decryptions...) That way a remailer could something like: #!/bin/sh if smime -f < incoming-message > /tmp/decrypted.$$ then # Process /tmp/decrypted fi rm incoming-message rm /tmp/decrypted.$$ The option would also be a very low-cruft-output -- there would be none of that PGP v2.6.2 stuff that PGP sends out. Just the decrypted output and if the message cant be decrypted, nothing gets output. (Maybe a -q option for that..) I think the smime should be easily plugged into premail as well, but I don't know premail to know what would be necessary for that. I suspect Raph would have some input on that matter.
The other day I was wondering what it would take to make an anonymous remailer for an S/MIME client. Implementing S/MIME from scratch is a lot of work given the lack of a public domain implementation, but it seems that a remailer could be built on top of a commercial email product that supported S/MIME. The question is: What features should a commercial S/MIME email product have to make it easy to support a remailer? Are there a small set of command line options that would greatly simplify a remailer implementation? --Bob Baldwin
-- sameer Voice: 510-601-9777 Community ConneXion FAX: 510-601-9734 The Internet Privacy Provider Dialin: 510-658-6376 http://www.c2.org (or login as "guest") sameer@c2.org
sameer writes, among other things:
A) limit on number of multiple concurrent procersses doing decryption. Remailer spams have the bad effect of spwaning hundreds of concurrent PGPs on the mailhost, bringing things to halt. Limiting number of concurrent decryptions would help this problem.
Agreed.
B) A strong interaction with the UNIX shell, with the program returning a return code based on whether or not the decryption succeeded. (Remailers only do decryptions...) That way a remailer could something like:
We very much need a command line interface to S/MIME, to use in remailers and also for other kinds of testing/hacking. I hope one is forthcoming soon.
I think the smime should be easily plugged into premail as well, but I don't know premail to know what would be necessary for that. I suspect Raph would have some input on that matter.
Raph does indeed have some input on the matter. I am currently rewriting premail from the ground up, and am about 700 lines into it. One specific design goal was the support of other types of encryption, including Mixmaster and MOSS in the first release, and hopefully others as well. Basically, I'm waiting on a command line S/MIME implementation as described above, most hopefully as free software. In any case, the new premail is _much_ more modular, so plugging in experimental email stuff should be pretty straightforward. Raph
baldwin , Robert W. Baldwin wrote:
The other day I was wondering what it would take to make an anonymous remailer for an S/MIME client. Implementing S/MIME from scratch is a lot of work given the lack of a public domain implementation, but it seems that a remailer could be built on top of a commercial email product that supported S/MIME. The question is: What features should a commercial S/MIME email product have to make it easy to support a remailer? Are there a small set of command line options that would greatly simplify a remailer implementation?
S/MIME is mostly PKCS#7. Eric Young is doing an implementation of PKCS#7 for his SSLEAY package. It seems like a good place to start... --Jeff -- Jeff Weinstein - Electronic Munitions Specialist Netscape Communication Corporation jsw@netscape.com - http://home.netscape.com/people/jsw Any opinions expressed above are mine.
participants (4)
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baldwin -
Jeff Weinstein -
Raph Levien -
sameer