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Re: [cryptography] [liberationtech] Random number generator failure in Rasperri Pis?
by Eugen Leitl 21 Jul '13

21 Jul '13

----- Forwarded message from Russell Leidich <pkejjy(a)gmail.com> ----- Date: Sat, 20 Jul 2013 16:17:32 +0000 From: Russell Leidich <pkejjy(a)gmail.com> To: cryptography(a)randombit.net Subject: Re: [cryptography] [liberationtech] Random number generator failure in Rasperri Pis? I agree, in theory. But: 1. How many register reads would one need in order to show Birthday compliance? (It's not the usual "root of the state space", because a single collision isn't convincing.) These reads tend to be slow, because the circuit designers generally need to guardband their entropy accrual to meet some particular minimum. In particular, we're looking for "good" evidence of a Poisson distribution, so we're up against a "lot" of reads relative to what Birthday attacks would suggest. If we don't have enough bits in memory to map the whole entropy register state space with acceptable access latency, then we have to do a realtime index-and-lookup of historical values, which is increasingly expensive over time. Even having generated said distribution successfully, the temperature and EMI background change with the wind. So wash, rinse, repeat. 2. More simply, we could generate a PRNG with a nice Poisson profile. While the initial read might be somewhat random in order to spoof a decent TRNG, subsequent reads would just iterate the PRNG, facilitating differential attacks. But this wouldn't be easy to detect if, say, I had 128 bits of state backing up a 32-bit fake TRNG register. 3. The hardware TRNG characterization process cannot be parallelized, because we need to determine the trustworthiness of the particular CPU in question. By contrast, an individual userspace TRNG (UTRNG) can be verified by simply comparing a hash of its executable code against expected public values. But we can't take the hash of a physical circuit. 4. Having verified that an individual UTRNG instance is identical to what's expected, the only remaining question is how fast it can generate entropy in the least entropic possible use case. That's not a trivial question to answer, but at least, parallel processing can accelerate this characterization. If it turns out to be a "good" TRNG, then at runtime, we can simply check the hash, rather than repeating the characterization because the physical environment is different. Again, I'm no quantum denialist. There's plenty of noise out there. But it's always nice to keep the trust radius to a manageable minimum. On Sat, Jul 20, 2013 at 12:59 PM, Dean, James <Jdean(a)lsuhsc.edu> wrote: > > Ø If my 64-bit hardware TRNG can only generate 1% of 64-bit numbers (probably because I hacked it), how are you going to discover that anytime soon? > > > > Test for more collisions than predicted by the birthday paradox. > > > _______________________________________________ > cryptography mailing list > cryptography(a)randombit.net > http://lists.randombit.net/mailman/listinfo/cryptography > _______________________________________________ cryptography mailing list cryptography(a)randombit.net http://lists.randombit.net/mailman/listinfo/cryptography ----- End forwarded message ----- -- Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org ______________________________________________________________ ICBM: 48.07100, 11.36820 http://ativel.com http://postbiota.org AC894EC5: 38A5 5F46 A4FF 59B8 336B 47EE F46E 3489 AC89 4EC5

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domain change
by Riad S. Wahby 20 Jul '13

20 Jul '13

Friends, A few people expressed some discomfiture off-list with the @al-qaeda.net domain name. I'm not so attached that I'm willing to alienate posters, so I've registered cpunks.org and updated the configs to reflect this. Note that the way I have things configured, the mail server doesn't much care which domain you submit to: if you're so inclined, cypherpunks(a)al-qaeda.net should continue to work as a submission address, ditto cypherpunks(a)jfet.org (which it seems remained in use until somewhat recently). I promise the administrative noise level on the list should return to near-zero after this, assuming no one feels like flaming me about the change. -=rsw

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War is Boring: Someone Just Built a Robot Sentry Gun
by BizDevCon (L0R3NZ 5Z4B0) 20 Jul '13

20 Jul '13

War is Boring: Someone Just Built a Robot Sentry Gun July 19, 2013 Robert Beckhusen NatSec writer at Medium. Contributor to Offiziere.ch It only shoots foam bullets, but that doesn't mean we shouldn't be worried Here's how German engineering student Britt Liv Ulrike Michelsen turned a Nerf gun into a robot. First, she connected the toy's electric motor to a microcontroller and a laptop computer, upgraded the firing spring to make it shoot faster and more accurately then connected the toy to a servo-driven stand, which allows it to swivel back and forth. Finally, she added a webcam and the open-source program Project Sentry Gun to make the device automatically track and attack anything that moves. End result: an automated, foam-firing robot sentry gun. Michelson's toy itself is harmless, but the idea behind it does raise some provocative questions. How easy is it to automate a real gun? What are the legal and ethical issues? (Spoiler: there are many.) And could we soon see automated weapons in the home? For help, we asked Patrick Lin, a professor at California Polytechnic State University and a leading researcher on the ethics of robots, drones and unmanned machines. We also wanted to know what the Pentagon is doing with its own armed ground 'bots. "What seems to be newsworthy is that a Nerf gun is involved, and some people may be unnerved by the juxtaposition of childhood innocence and visions of Terminator-style AI," Lin says. "But a Nerf gun isn't usually lethal, though it could harm targets if they were hit in the eye, for instance. So a non-lethal home security robot could be permitted by law, depending on how harmful it is." A pepper-spraying home defense 'bot might go too far. A lethal autonomous sentry gun is out of the question, not the least of which is the inability to distinguish between an intruder and an innocent child. "Just like you can't rig a shotgun to shoot whatever opens your door," he adds. "The big problem here is that it would be an indiscriminate attack, even in states with 'Stand Your Ground or 'Castle' laws that permit lethal defense of the home." The capability exists -- though only for the military. Years ago, Samsung defense subsidiary Samsung Techwin developed a robotic machine gun, the SGR-A1, which is also equipped with infrared cameras. The 'bot's destination was reportedly the South Korean side of the Korean demilitarized zone, but these were never deployed or turned into full-auto mode. The Pentagon has its own projects. A weaponized robot called SWORDS was deployed to Iraq -- under Army control -- until funding was yanked. A follow-up program by the Marines, called MAARS, can roll around with a swappable weapons system, including both lethal bullets and non-lethal grenades and laser dazzlers. Its developer, defense contractor QinetiQ, describes the robot as "taking its place on the frontlines to keep warfighters at a safe distance from enemy fire while effectively executing security missions." MAARS hasn't been deployed and has not been made autonomous. The Pentagon is also very skeptical about taking its own personnel out of the decision-making process with it comes to lethal robots and drones. "The important point, though, is that the capability already exists today," Lin says. "If it were to be deployed, that would be an important and, to many, regrettable milestone in future warfare." But should we be worried about someone making a killbot at home and then automating to do something terrible? Sort of. Maybe. It's possible someone could do it. "It would seem so," Lin says. "But there are a lot of terrible things people can make that thankfully don't appear very much, such as privacy-infringing or bomb-carrying drones. We have laws that address most of those contingencies, and that seems to be enough to deter most rational people inclined to try them out." One thing to watch out for, he notes, is for an engineer or activist to develop a lethal sentry gun just to provoke a debate, create a backlash or force regulation. We've seen that happen with 3-D printed guns. But even criminals getting ahold of those are a big stretch. Lin says, "Luckily, criminals tend to be dumb -- not so much the Lex Luthor type." Subscribe to War is Boring: medium.com/feed/war-is-boring.

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Testing with a joke
by BizDevCon 20 Jul '13

20 Jul '13

Testing with a joke: Q: What is the longest 10 years in the lifetime of a woman? A: Between 38 and 42.

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Re: [tor-talk] Network diversity [was: Should I warn against Tor?]
by Eugen Leitl 20 Jul '13

20 Jul '13

----- Forwarded message from Gregory Maxwell <gmaxwell(a)gmail.com> ----- Date: Fri, 19 Jul 2013 13:42:03 -0700 From: Gregory Maxwell <gmaxwell(a)gmail.com> To: tor-talk(a)lists.torproject.org Subject: Re: [tor-talk] Network diversity [was: Should I warn against Tor?] Reply-To: tor-talk(a)lists.torproject.org On Fri, Jul 19, 2013 at 9:45 AM, adrelanos <adrelanos(a)riseup.net> wrote: > Seems like high latency mix networks failed already in practice. [1] > > Can't we somehow get confidence even against a global active adversary > for low latency networks? Someone start a founding campaign? So have low latency ones, some things fail. Today you'd answer that concern by running your high latency mix network over tor (or integrated into tor) and so it cannot be worse. Answering the "you need users first, and low latency networks are easier to get users for" concern. The point there remains that if you're assuming a (near) global adversary doing timing attacks you cannot resist them effectively using a low latency network. Once you've taken that as your threat model you can wax all you want about how low latency mix networks get more users and so on.. it's irrelevant because they're really not secure against that threat model. (Not that high latency ones are automatically secure either— but they have a fighting chance) On Fri, Jul 19, 2013 at 10:03 AM, Jens Lechtenboerger <tortalk(a)informationelle-selbstbestimmung-im-internet.de> wrote: >> but going much further than that may well decrease your security. > > How, actually? I’m aware that what I’m doing is a departure from > network diversity to obtain anonymity. I’m excluding what I > consider unsafe based on my current understanding. It might be that > in the end I’ll be unable to find anything that does not look unsafe > to me. I don’t know what then. Because you're lowering the entropy of the nodes you are selecting maybe all the hosts themselves are simply NSA operated, or if not now, they be a smaller target to compromise. Maybe it actually turns out that they all use a metro fiber provider in munich which is owned by an NSA shell company. In Germany this may not be much of a risk. But if your logic is applied to someplace that is less of a hotbed of Tor usage it wouldn't be too shocking if all the nodes there were run by some foreign intelligence agency. _______________________________________________ tor-talk mailing list tor-talk(a)lists.torproject.org https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-talk ----- End forwarded message ----- -- Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org ______________________________________________________________ ICBM: 48.07100, 11.36820 http://ativel.com http://postbiota.org AC894EC5: 38A5 5F46 A4FF 59B8 336B 47EE F46E 3489 AC89 4EC5

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Re: [tor-talk] Network diversity [was: Should I warn against Tor?]
by Eugen Leitl 20 Jul '13

20 Jul '13

----- Forwarded message from Gregory Maxwell <gmaxwell(a)gmail.com> ----- Date: Fri, 19 Jul 2013 09:33:45 -0700 From: Gregory Maxwell <gmaxwell(a)gmail.com> To: tor-talk(a)lists.torproject.org Subject: Re: [tor-talk] Network diversity [was: Should I warn against Tor?] Reply-To: tor-talk(a)lists.torproject.org On Fri, Jul 19, 2013 at 8:35 AM, Jens Lechtenboerger <tortalk(a)informationelle-selbstbestimmung-im-internet.de> wrote: > [For those who are confused about the context of this: I started the > original thread. A write-up for my motivation is available at [0].] I > Links to my code and a README.txt clarifying necessary prerequisites are > available at [0]. Best wishes Jens [0] > https://blogs.fsfe.org/jens.lechtenboerger/2013/07/19/how-i-select-tor-guar… It's _very_ hard to reason about this subject and act safely. It is common for ISPs to use segments in their network which are provided by third party providers, even providers who are almost entirely facilities based will have some holes or redundancy gaps. Because these are L1 (wave) and L2 (e.g. ethernet transport) they are utterly invisible from the L3 topology. You can make some guesses which are probably harmless: a guard that is across the ocean is much more likely to take you across a compromised path than one closer— but going much further than that may well decrease your security. These concerns should be reminding us of the importance of high latency mix networks... they're the only way to start getting any real confidence against a global passive observer, and the are mostly a missing item in our privacy tool toolbelt. _______________________________________________ tor-talk mailing list tor-talk(a)lists.torproject.org https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-talk ----- End forwarded message ----- -- Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org ______________________________________________________________ ICBM: 48.07100, 11.36820 http://ativel.com http://postbiota.org AC894EC5: 38A5 5F46 A4FF 59B8 336B 47EE F46E 3489 AC89 4EC5

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back on the airwaves
by Riad S. Wahby 20 Jul '13

20 Jul '13

All, Welcome back to the Cypherpunks mailing list. You've received a subscription notice and are receiving this message now because you were a member of the cypherpunks(a)al-qaeda.net or cypherpunks(a)jfet.org mailing list before it went offline several (?) weeks ago. First, my sincerest apologies for having failed to notice that messages were silently dropping. All the bounces were still dropping into my "cypherpunks bounces" mailbox, so from what I could tell all was running normally (if perhaps at slightly low SNR). It turns out that some package upgrade, most likely a new version of perl, broke majordomo. (And of course, could I have picked a worse time to break everything?) Well, that's the bad news. The good news is that cypherpunks is now powered by Mailman, and should be a bit more reliable, easier to maintain, and less Rube-Goldbergian. (I say this with all respect to my cpunk admin predecessors; the CDR was a useful and interesting piece of software, but---at least, in its most recent form---it was certainly not a *pretty* piece of software.) Nevertheless, since I haven't actually done much other than port the old majordomo list over to mailman, the Distributed Remailer functionality no longer obtains. Practically, this hasn't mattered for at least the last 6 or 8 years, but perhaps that would change if I would just modernize the software a bit. I'm planning on putting some thought into that in the near future, but for now I figured it was more important to just get *something* back up and running. Once again, welcome back! -=rsw

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