Risks of using usually-reliable information sources in your programs
I've been thinking about building remailers and cover-traffic generators, and there's a need for a convenient up-to-date list of remailers. Raph Levien's remailer pinging service is definitely convenient, and even produces some of its output in perl for use by perl programs. However, it's important to be really careful when depending on information like this, e.g. when building it into programs, because otherwise it's easy to trick them into using bogus data, such as the crudely forged article sent to Cypherpunks earlier today. The natural implementation is to pick the more reliable remailers based on "Raph"'s statistics, so adding records for very reliable bogus remailers is a win. The security would be improved if Raph signed the weekly file, but that also requires people using the file to check it with PGP and not just grep out the relevant lines for their programs' use.
X-Sender: stewarts@popd.ix.netcom.com X-Mailer: QUALCOMM Windows Eudora Light Version 3.0.3 (32) Date: Sun, 05 Oct 1997 18:06:56 -0700 To: cypherpunks@toad.com From: Raph Levien <raph@CS.Berkeley.EDU> Subject: List of reliable remailers Sender: owner-cypherpunks@cyberpass.net Reply-To: Raph Levien <raph@CS.Berkeley.EDU> X-Loop: cypherpunks@cyberpass.net
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I operate a remailer pinging service which collects detailed information about remailer features and reliability. .... recovery remailer@biglouie.fbi.gov ############ 0:01 99.99% payswell remailer@digicrime.com ############ 0:01 99.99% trustme trustme@trustme.nsa.mil ************ 0:59 99.99% mulder mulder@juno.com #*#*##*#*#*# 0:57 99.98%
Thanks! Bill Bill Stewart, stewarts@ix.netcom.com Regular Key PGP Fingerprint D454 E202 CBC8 40BF 3C85 B884 0ABE 4639
-----BEGIN PGP SIGNED MESSAGE----- On Sun, 5 Oct 1997, Bill Stewart wrote:
to pick the more reliable remailers based on "Raph"'s statistics, so adding records for very reliable bogus remailers is a win.
Incidentally, I think the patches I have for premail would probably reduce the effects of an attack like this. It adds a reliability-threshold and latency-threshold. Any remailer more reliable than the reliability-threshold (recommended: 99.5%) is treated as if the uptime was 100%. Latencies lower than the latency threshold are treated as zero. On a good day, this means there are several remailers which will score exactly the same before the shuffling factor is added. The four spook remailers listed would all score the same as squirrel and bureau42, which have latencies exceeding 3 hrs: recovery remailer@biglouie.fbi.gov ############ 0:01 99.99% @ payswell remailer@digicrime.com ############ 0:01 99.99% @ trustme trustme@trustme.nsa.mil ************ 0:59 99.99% @ mulder mulder@juno.com #*#*##*#*#*# 0:57 99.98% @ cracker remailer@anon.efga.org +*+*+***++*+ 15:42 99.99% @ nym config@nym.alias.net **#**###**** :39 99.99% jam remailer@cypherpunks.ca +*++*++++++* 22:24 99.98% @ redneck config@anon.efga.org ############ :37 99.98% privacy remailer@privacynb.ml.org #*#***** 1:47 99.98% @ neva remailer@neva.org --+*-+**+**- 1:15:36 99.97% @ mix mixmaster@remail.obscura.com + -********* 40:27 99.83% @ winsock winsock@rigel.cyberpass.net -------..+- 9:45:21 99.79% % squirrel mix@squirrel.owl.de ------+--+- 3:04:59 99.74% @ bureau42 remailer@bureau42.ml.org ----------- 3:09:39 99.53% @ reno middleman@cyberpass.net +* * + +++* 30:42 99.44% # replay remailer@replay.com **** * *** 4:01 99.00% # hera goddesshera@juno.com ---- .------ 5:18:04 97.77% htuttle h_tuttle@juno.com ---- - ----+ 3:02:37 97.49% # arrid arrid@juno.com - - -.-- 9:23:33 81.91% tea tea@notatla.demon.co.uk - 19:27:50 1.92% @ = all score identically (not counting other bonuses from various config flags), 100% uptime, 0 latency % = 100% uptime # = 0 latency See http://anon.efga.org/anon/premail.efga.patch. This is not why I came up with the patch. Originally I came up with the reliability-threshold when I was running as a middleman and wanted to make sure I was picking good remailers. I find that for chaining, chain lengths of 1 and 2 tend to be somewhat slower on average than with standard premail. However, longer chains tend to be significantly faster and even more reliable. Check out http://anon.efga.org/anon/remailer-chains.html and look at the distribution of remailers selected in chains, and compare my random chain stats against Raph's. (I have a couple of remailers he doesn't, AFAIK.)
The security would be improved if Raph signed the weekly file, but that also requires people using the file to check it with PGP and not just grep out the relevant lines for their programs' use.
Agreed, but the danger from attack like this lies with automatic chaining programs, where the user may not even be aware of what remailers are on the list, or what remailers were chosen. A PGP-signed version would improve things, particular if a special signing key is used, and that key is stored in a separate keyring. This PGP-version may have to be available separately from the regular remailer list to avoid confusing chaining programs. I'll see if I can whip up a PGP-signed version of the EFGA remailer list by the end of the day. Andy Dustman / Computational Center for Molecular Structure and Design / UGA To get my PGP public key, send me mail with subject "send file key". For the ultimate anti-spam procmail recipe, send me mail with subject "spam" "Encryption is too important to leave to the government." -- Bruce Schneier http://www.athens.net/~dustman mailto:andy@CCMSD.chem.uga.edu <}+++< -----BEGIN PGP SIGNATURE----- Version: 2.6.3ia Charset: noconv iQEPAwUBNDjmWxOPBZTHLz8dAQGjaAfPY9KOWVqyi6egyZqAxt+SOCCeWmfWTxvr UUqWdT4NcdwH52jJnlflLsUZr6c2TtgGoYkXrltH+rzhTNWWGfTSuQgyshuNNRfP Lk6W/y8bsaroFrFccME5vq4M+L9izQekosf+e1muu4X9tJKk5ksCS5bfOQaVLQum ueouSvQOc3dmn4J64R5Wih6iMOrsYusqIj30Dz3SZFjOCbNb7VC66WdF/GafHItw RJiRVZnOsT0igtqTe25ywO097fiGhwld4L2rOGjsLUag4vqbjaf+5NCGl3Dshq0C fcmSPfYXGAvk3/ZxjSjQ2VE1OAEPvde4MiQrTj9PdvFflA== =Xz3V -----END PGP SIGNATURE-----
participants (2)
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Andy Dustman -
Bill Stewart