home *** CD-ROM | disk | FTP | other *** search
- Path: sparky!uunet!charon.amdahl.com!pacbell.com!mips!sdd.hp.com!usc!orion.oac.uci.edu!beckman.com!dn66!a_rubin
- Newsgroups: sci.crypt
- Subject: Re: Secure netnews
- Message-ID: <a_rubin.714242242@dn66>
- From: a_rubin@dsg4.dse.beckman.com (Arthur Rubin)
- Date: 19 Aug 92 16:37:22 GMT
- References: <9208182108.AA09132@news.cis.ohio-state.edu> <1992Aug18.221506.13535@Princeton.EDU>
- Nntp-Posting-Host: dn66.dse.beckman.com
- Lines: 56
-
- In <1992Aug18.221506.13535@Princeton.EDU> dla@raven (Don Alvarez) writes:
-
- >In article <9208182108.AA09132@news.cis.ohio-state.edu> Marc.Ringuette@daisy.learning.cs.cmu.edu writes:
- >>
- >>The basic technique I propose in order to achieve this is a two-stage news
- >>distribution process, where first the news is distributed to the entire set
- >>of receiving machines, then signatures are collected from all receivers and
- >>distributed in the same way as a regular news article.
- >>
- >>Machines must register themselves by posting to the newsgroup, and must agree
- >>to respond to signature requests within a reasonable window, or they will be
- >>removed from the set of participating hosts.
- >>
- >>What do you think? See any gaping holes? Want to flesh it out and
- >>give it a try?
- >>
- >> --Marc Ringuette, mnr@cs.cmu.edu
-
- >Gaping holes? *YES*
-
- >There is no central authentication server, so every subscriber must be
- >able to determine authentication themselves. That means every
- >subscriber needs a list of the names of all of the other subscribers.
-
- >Any subscriber can fraudulently "authenticate" any posting simply by
- >greping through the list of subscribers and announcing "subscriber foo
- >received article 754", "subscriber bar received article 754", etc.
-
- Actually, if the "signatures" are cryptographic, there may be a solution to that.
- You have to define "subscribers" as key-holders rather than as machines,
- but it seems somewhat reasonable.
-
- ...
-
- >Worse, there is no way for any machine even to know that it has a complete
- >or accurate list of subscribers because there is no way to distribute
- >such a list in a trusted manner.
-
- That's true.
-
- >Providing a centralized server for doing the authentication wouldn't
- >help, because there is no way for it to know who is sending the
- >subscription messages or who is sending the receipt messages. There
- >would also be no way for the individual subscribers to know who sent
- >the "article 754 authenticated" message.
-
- That's not correct. If you believe public key signature systems can be
- secure, then a message can be posted which has the effect that "someone
- with key K1 posted message M1".
-
-
- --
- Arthur L. Rubin: a_rubin@dsg4.dse.beckman.com (work) Beckman Instruments/Brea
- 216-5888@mcimail.com 70707.453@compuserve.com arthur@pnet01.cts.com (personal)
- My opinions are my own, and do not represent those of my employer.
- My interaction with our news system is unstable; if you want to be sure I see a post, mail it.
-