December 2003 - cypherpunks-legacy

Perfect Forward Secrecy - is it worth it?
by Simon Spero 17 Dec '03

17 Dec '03

Quick survey; how important is perfect forward secrecy to you? I've asked three people locally so far and gotten four different answers, so in the spirit of spreading divisiveness where'er I go, I'll try and get a few more opinions here :-) In general, schemes offering PFS require a extra PK-op, and an extra round-trip when compared to non-PFS schemes. This cost is incurred once per "session", but can add on the order of seconds to startup times. Should key-management schemes where PK is available always provide PFS, allow PFS, or not provide PFS? The amount of code needed to implement each choice point is similar, if you're using something like BSAFE. Simon --- (defun modexpt (x y n) "computes (x^y) mod n" (cond ((= y 0) 1) ((= y 1) (mod x n)) ((evenp y) (mod (expt (modexpt x (/ y 2) n) 2) n)) (t (mod (* x (modexpt x (1- y) n)) n))))

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Re: /dev/random for FreeBSD [was: Re: /dev/random for Linux]
by Mark Murray 17 Dec '03

17 Dec '03

> How about SetGID? We were going for 660 root.kmem. > > Bad idea; anyone who can run PGP could then get instant access to kmem Fooey. Of course. Scratch that plan. > cd /tmp > ln -s /dev/kmem foo > pgp -e tytso foo > rm foo > pgp foo.pgp Eeeeek! > ? "Gut feel" suggests to me that large ammounts of "predicted" input might > be worse than the normal sort of system noise you have been using. > > But keep in mind that what we're doing is XOR'ing the input data into > the pool. (Actually, it's a bit more complicated than that. The input > is XOR'ed in with a CRC-like function, generated by taking an > irreducible polynomial in GF(2**128). But for the purposes of this > argument, you can think of it as XOR.) So since you don't know what the > input state of the pool is, you won't know what the output state of the > pool. I chatted with a colleague at work, and he helped bend my mind right. I had the mistaken notion that adding lots of data would "overflow" and "dilute" the entropy to an attackable state. > Is this millisecond accuracy quantifiable in terms of bits of entropy? > if so, the ethernet is surely safe? > > Well, no. If you're only using as your timing the 100Hz clock, the > adversary will have a better timebase than you do. So you may be adding > zero or even no bits of entropy which can't be deduced by the adversary. In a 386 or a 486 (under FreeBSD at least) there is a 1Mhz clock available. How would _this_ be? On the Pentium there is the <whatsit?> register which will give the board's oscillator (or 90 MHz) I believe. > This is even worse in the PGP keyboard timing case, since the adversary > almost certainly can find a better time resolution to measure your > incoming packets when compared to the timing resolution that most > programs have. Far too many Unix systems only make a 100Hz clock > available to the user mode, even if you have a better quality high > resolution timing device in the kernel (for example, the Pentium cycle > counting register). Ah yes - _that_ register. :-) What then is a body to do? Preserve all _verifiable_ randomness like gold? Dish it out under some quota? A denial of service attack would be forever { cat /dev/random > /dev/null } Severely limiting most decent folk's chance at getting PGP to work. Right now I am considering making a piece of cheap hardware to deliver noise to a digital input. (Electronics is a stagnant hobby of mine) Interested? I may knock up a prototype in a month or so... > The problem is that in order to do this requires making assumptions > about what the capabilities of your adversary are. Not only does this > change over time, but certain adversaries (like the NSA) make it their > business to conceal their capabilities, for precisely this reason. Can they predict thermal noise in a cheap transistor? ]:-> > So I like to be conservative and use limits which are imposed by the > laws of physics, as opposed to the current level of technology. Hence, > if the packet arrival time can be observed by an outsider, you are at > real risk in using the network interrupts as a source of entropy. > Perhaps it requires buidling a very complicated model of how your Unix > scheduler works, and how much time it takes to process network packets, > etc. ---- but I have to assume that an adversary can very precisely > model that, if they were to work hard enough at it. This is a strong argument for some form of specialised noise source. I have read of methods of getting this from turbulent air flow in a hard drive (an RFC, I believe). > People may disagree as to whether or not this is possible, but it's not > prevented by the laws of physics; merely by how much effort someone > might need to put in to be able to model a particular operating system's > networking code. In any case, that's why I don't like depending on > network interrupts. Your paranoia level may vary. If I was running Fort Knox, I'd probably use Radioactive decay... (From my experience working at a cyclotron facility - these SOB's are _*RANDOM*_) M -- Mark Murray 46 Harvey Rd, Claremont, Cape Town 7700, South Africa +27 21 61-3768 GMT+0200 Finger mark(a)grumble.grondar.za for PGP key

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InfoWar
by nobody＠REPLAY.COM 17 Dec '03

17 Dec '03

The Wall Street Journal, October 31, 1995, p. B1. It's Time You Became A Manager of Change, The Consultants Say [Excerpts] Rapid innovation and product introduction require a nimbleness lacking in many corporate bureaucracies. "There's an intrinsic need to improve your effectiveness at managing change -- whatever form it takes," says David Nadler, chairman of the New York-based Delta Consulting Group. Change-management boosters are also telling managers to learn about "knowledge management" as a means of achieving their new goals. Knowledge management attempts to make fuller use of internal information networks. The consulting units of Arthur Andersen, Ernst & Young and Price Waterhouse are peddling systems to collect, store and distribute knowledge. Andersen designates "knowledge managers" who monitor traffic through its Lotus Notes e-mail software and store valuable information on a CD- ROM. The disk contains 16,000 pages on everything from performance measurements to employee motivation. One problem with the system: "It's so difficult to tie knowledge-management systems to bottom-line improvement," says C. Jack Grayson Jr., whose American Productivity and Quality Center co-sponsored a knowledge-management symposium with Arthur Andersen. "That just feeds suspicions that it's just another fad." It's also difficult to get employees to contribute to the information pool [fearful their jobs may vanish after overt knowledge-transfer, hence, the appeal to managers for systems that covertly siphon knowledge and record grounds for dismissal]. ------ WSJ, October 24, 1995, p. A24. Privacy Laws Are Lax On New Technology, Federal Agency Says Washington -- Inconsistent privacy laws let companies sell sensitive information about consumers who use new communications technologies, the Clinton administration warned. In a report, the Commerce Department's National Telecommunications and Information Administration called on communications companies to tell customers if they plan to sell information about what they watch or whom they call, and to make it easy for customers to squelch the disclosure of sensitive information. Federal regulations allow people to ask their phone company to keep information confidential, but the rule generally doesn't apply to small phone companies or wireless phones, according to the report. Laws that prevent video stores from disclosing what movies customers watch don't apply to pay-per-view services by satellite-television providers. And while a 1986 law prevents on-line computer services from snooping into electronic mail, it doesn't prevent the services from selling information about who e-mailed whom, and what the topic was, the report noted. The Commerce Department stopped short of calling for legislation to close the gaps. But "if industry doesn't do it, consumers will demand that the government do it," predicted Larry Irving, assistant commerce secretary for communications and information. Industry representatives played down the privacy loopholes. Ronald Plesser, a Washington attorney who represents online services and direct marketing firms, said, "I know of no example of anybody trafficking in e-mail descriptions." A spokeswoman for Hughes Electronics Corp.'s DirecTV said, "We do not release names of customers that ordered movies. -----

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Re: FCPUNX:Macintosh [and perhaps other OS] Security Alert (fwd)
by Ray Arachelian 17 Dec '03

17 Dec '03

========================================================================== + ^ + | Ray Arachelian | Amerika: The land of the Freeh. | _ |> \|/ |sunder(a)dorsai.org| Where day by day, yet another | \ | <--+-->| | Constitutional right vanishes. | \| /|\ | Just Say | | <|\ + v + | "No" to the NSA!| Jail the censor, not the author!| <| n ========================================================================== ---------- Forwarded message ---------- Date: Sat, 28 Oct 1995 11:12:00 -0400 From: Sal Denaro <Sal(a)panix.com> To: Ray Arachelian <sunder(a)amanda.dorsai.org> Subject: Re: FCPUNX:Macintosh [and perhaps other OS] Security Alert (fwd) > ---------- Forwarded message ---------- > Date: Sun, 15 Oct 1995 01:05:06 -0400 > From: Lucky Green <shamrock(a)netcom.com> > To: cypherpunks(a)toad.com > Subject: Macintosh [and perhaps other OS] Security Alert > > -----BEGIN PGP SIGNED MESSAGE----- > > A number of months ago, I discovered that various Macintosh "unused > diskspace" wipe utilities (Norton, Burn) fail to wipe the unused > slackspace at the end of the last block allocated to a file. This leaves > NumberOfFiles*512Bytes/2 = several kB of recoverable data on your average > drive. > I can verify that this is a cross-platform bug. The Dos/win3.1 and Win95 versions all have the same flaw. -- Salvatore Denaro sal(a)panix.com Spinning dreams with angel wings Yes, I use PGP torn blue jeans/a foolish grin

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Re: /dev/random for FreeBSD [was: Re: /dev/random for Linux]
by Mark Murray 17 Dec '03

17 Dec '03

> In a 386 or a 486 (under FreeBSD at least) there is a 1Mhz clock available. > How would _this_ be? On the Pentium there is the <whatsit?> register > which will give the board's oscillator (or 90 MHz) I believe. > > What's HZ set at for FreeBSD? Most of the x86 Unixes have generally > used HZ set at 100, because the interrupt overhead on a x86 isn't cheap, > and so you want to limit the number of clock interrupts. There are two interrupts 100Hz and the other 128Hz (The second gets pushed into the +-1K region during profiling. > You can sample the timing clock, but it turns out to be rather expensive > to do so; several I/O instructions, which will require several delays if > they have to go through your 8 MHz ISA bus. We've moved away from using > the hardware clock on the 386 because of the overhead concerns. On the > Penitum, we use the clock cycle counter. Drat. Methinks I need to follow suit, but I value that 1Mhz... > Well, verifiable randomness really is like gold. It's a valuable > resource. On a time-sharing system, where you really want to equitably > share *all* system resources perhaps there should be a quota system > limiting the rate from which a user is allowed to "consume" randomness. True. VMS could probably do this. <Ducks bricks> > On the other hand, most Unix systems *aren't* great at doing this sort > of resource allocation, and there are enough other ways of launching > denial of service attacks. "while (1) fork();" will generally bring > most systems to their knees, even in spite of limitations of the number > of processes per user. Most Unix systems don't protect against one user > grabbing all available virtual memory. And so on.... Getting there (I think). > There's nothing special about /dev/random in this sense; it's just > another system resource which can be abused by a malicious user, just > like virtual memory or process table slots. True. Good policing never hurt. > This is a strong argument for some form of specialised noise source. > I have read of methods of getting this from turbulent air flow in a hard > drive (an RFC, I believe). > > Yes, ultimately what you need is a good hardware number generator. > There are many good choices; from radioactive decay, noise diodes, etc. The idea that I like the most so far is to generate noise, but filter it through an LPF to get frequencies less than (say) 500Khz. Put that through schmitt trigger to get decent squarewaves and then into an N-bit hardware shift register with some XOR feedbacks to mix this. Voila! Nice numbers on demand. Shouldn't cost more than a few <shekels>... > Short of good hardware sources, the other really good choice is > unobservable inputs. Hence, the Linux driver is hooked into the > keyboard driver, and the various busmice drivers. Those are really > wonderful sources of randomness, since they're generally not observable > by an adversary, and humans tend to be inherently random. :-) Doesn't work on servers in locked rooms... :-( With those, as long as the machines are secure, (ie plebs cannot watch and time raw packets) the network card is OK. The server may not be on transit ethernet AT ALL. M -- Mark Murray 46 Harvey Rd, Claremont, Cape Town 7700, South Africa +27 21 61-3768 GMT+0200 Finger mark(a)grumble.grondar.za for PGP key

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Re: Keyed-MD5, ITAR, and HTTP-NG
by Rich Salz 17 Dec '03

17 Dec '03

All your individual answers make sense. Taken together, tho, they make HTTP-NG worrisome on the crypto front. For example, it's probably a real bad idea to replace DES with something commonly called RC4. The former has been under public scrutiny for years, the later still has not formally emerged from the shroud of trade secret. The keyed MD5 responses also don't inspire confidence. With all due respect, I strongly encourage you to leave crypto out of HTTP-NG for the time being. Wait to see what happens from the various IPng security, SSL, S-HTTP, the W3C work, et cetera. Leave some "holes" in the protocol, but don't tie anything down now. For better for the Web to wait six to 12 months for HTTP-NG, then for mistakes to occur in this area. /r$

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A final Huber-Spam: ON MONEY
by rah＠shipwright.com 17 Dec '03

17 Dec '03

Note the URL. There's more there for them as wants 'em. Cheers, Bob Hettinga --- begin forwarded text Date: Tue, 31 Oct 95 21:32:44 0500 From: Robert Hettinga <rah(a)shipwright.com> Organization: Shipwright MIME-Version: 1.0 To: rah(a)shipwright.com Subject: 031692.html X-URL: http://khht.com/huber/forbes/031692.html http://khht.com/huber/forbes/031692.html> ON MONEY > > by Peter Huber > > Forbes, March 16, 1992 at Pg. 144 > > Copyright 1992 by Peter Huber. Electronic copies of this document > may be distributed freely, provided that this notice accompanies all > copies. > > ------- > > While Europe strains to give birth to a new currency, Boris Yeltsin > toils to resurrect a dead one. With private markets triumphant > everywhere else, however, the mystery is why governments still have > to manufacture money at all. > > It is still often taken for granted that the one thing private > markets cannot make is money itself: Only government can do that. > But new governments of young nations, especially nations with > turbulent histories, can't make money, either. Nobody quite trusts > them, and without trust the paper lovingly engraved at the > government mint is valueless. > > Until recently, people put up with a lot of government paper because > even bad paper was more convenient than the alternative, which was > barter. Every self-respecting capitalist knew that government paper > was a perishable good, that it always decayed, slowly in > Switzerland, fast in Brazil, and most just put up with it. But if > capitalists can produce candies that melt in your mouth, not in your > hand, why not currencies, too? > > Money, as I wrote here two years ago (FORBES, May 14, 1990), is just > another network, our oldest medium of systematic communication. And > new communications technologies are fast surpassing the old. The > paperless bank, unlike the paperless office, is at hand. > > When it works, the old-fashioned paper we call money reliably > records past effort and promises future return. It's all a matter of > communication among stable communities of productive people. This is > why individuals can issue currencies, too -- personal checks, IOUs, > that sort of thing. Once it's established of an individual that her > word is her bond, she can in fact issue private currency at will, at > least among people who know her. > > But the trouble with private currencies has always been their > informational overhead. Personal checks bounce, the "I" behind the > IOU absconds to Monaco, Macy's defaults on its bonds. Private paper > is also volatile; pegging current value requires specialized > information from Wall Street, or a bank in Oshkosh, or a trading pit > in Chicago. In the past, it's often been cheaper to put up with the > steady but modest thievery of a central bank, which peels off 3% > (will it soon be 6%?) of your dollar every year through inflation, > than to sort out whose private paper is worth what at any given > moment. > > Computers and fiber-optic communications are changing all that. Our > new central bankers can be concerns like TRW and Dun & Bradstreet, > which track who's solvent and who's a deadbeat and convey the > information instantly, at the touch of a button, wherever it's > needed. Our new mints and engravers can be companies like Visa and > AT&T, which clear millions of transactions daily, both here and > abroad. > > What enterprises like these supply are the informational ingredients > of money. They already are far better than Alan Greenspan at > stabilizing value by assembling baskets of private paper as varied > and diversified as the global economy. Information about who earned > a credit yesterday or who can be trusted to pay back a debt tomorrow > can be passed around as easily as a dollar bill. More easily, in > fact. > > Like religious liturgies conducted in some otherwise dead language, > transactions may still be denoted in dollars or yen, but these > vestiges of an earlier age will ultimately give way to a new > financial vernacular. If everybody paid for everything (wages > included) by credit card, for example, the accounts could just as > well be denoted in pork bellies, IBM stock, quarterpounders with > cheese, or (more likely) some very large basket of hundreds of > different private goods and services, tangible and intangible. > > The Lynch, for example, might be a share in a standard pool of > commodity receipts maintained by Merril Lynch. Nobody would fully > trust the Lynch, of course, even if backed by 100% reserves, but > nobody would have to. Nobody trusts his food supply to any one > farmer, either. You diversify, you assemble baskets of baskets, and > you constantly search for quality goods and reliable supply. Same > with money. When the network and the computers behind it are > powerful enough, no central authority can or should supply the > currency, and no one will pay annual tribute by way of inflation to > the government mint. And with private money, private fortunes will > no longer be held hostage to public ineptitude in the Kremlin or on > Capitol Hill. > > So back to Yeltsin and how we can help him. Despite the corrupting > influences of the regulatory collectivist on our own shore, > America's phone companies and banks are still the best in the world. > Yeltsin needs them, far more than he needs the International > Monetary Fund, Pizza Hut or Western investment in Russia's oil > industry. Modern telefinancial enterprises can deliver the real oil > of the economy: truly stable media of exchange. > > The biggest contribution Yeltsin can make to Russia's fiscal policy > is to make way for currency capitalists. No exchange controls, no > bank insurance, no loan guarantees, no criminal prosecution for > ordinary bankruptcy, nothing but basic, narrowly interpreted laws > against outright fraud. > > Will the new private banks sometimes fail? Of course they will. Will > widows then be ruined? Certainly. So what else is new? In Russia > today the only bank in town has failed miserably, and the one cold > comfort for widows is that the ruin is universal. Give it a try, > Boris. You have nothing to lose but your rubles. --- end forwarded text ----------------- Robert Hettinga (rah(a)shipwright.com) Shipwright Development Corporation, 44 Farquhar Street, Boston, MA 02131 USA (617) 323-7923 "Reality is not optional." --Thomas Sowell >>>>Phree Phil: Email: zldf(a)clark.net http://www.netresponse.com/zldf <<<<<

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Re: /dev/random for FreeBSD [was: Re: /dev/random for Linux]
by Martin Diehl 17 Dec '03

17 Dec '03

Theodore Ts'o writes... >Yes, ultimately what you need is a good hardware number generator. ... >I'm not entirely comfortable with the proposal of using air flow >turbulance [sic] from a hard drive ... Two important observations about the use of a disk drive to get randomness: 1. In the case of some workstations, the local network provides the disk drive and there isn't a local hard drive at all. Hence, any timing of disk accesses will give you data that is influenced by the file server more than the disk drive. 2. When doing time domain measurements (Hewlett Packard had some good application notes on this subject), you must consider base clock jitter. Ill try to illustrate with a diagram: actual event: V V clock granularity: /...../...../...../...../...../...../ the problem is that no matter how small the basic clock unit is (symbolized by "/", above), you can't be sure how much of that unit has passed when the event (symbolized by "V", above) occurs. For example, on the original IBM PC, clock interrupts occurred about 18.2 times per second (55ms interval). In that architecture, you can't time an event and have an uncertainty of less than 2 times 55ms If you propose using a special hardware random generator, you have a different set of problems: 1. You need to buy and install hardware on many different platforms -- you don't always have access to do that. 2. Many earlier posts on this subject pointed out that removing bias was important. In that case, you need to continuously test and recertify the hardware random generator for randomness. In order to do that, you need to have so much knowledge about generating and testing random numbers in software that you might as well use a software solution in the first place. Good luck

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PGP 2.6.2 signator replacement bug fix
by Jim Castleberry 17 Dec '03

17 Dec '03

-----BEGIN PGP SIGNED MESSAGE----- Here's a fix for a minor bug in PGP 2.6.2. I reported it to pgp-bugs last February and they responded promptly, but it hasn't been propagated to the release - I suppose 2.6.2 is "in the freezer". Anyway, the bug can cause a crash and other folks might like to put in the fix, so here it is. Anyone have any others? Jim Castleberry jcastle(a)in-system.com Original bug report starts here: - ------------------------------------------------------------------------- I believe I've identified a bug in PGP 2.6.2. The bug occurs on my system: HP 9000/735, running HPUX 9.03 MIT PGP 2.6.2 Compiled with either the native cc or gcc 2.6.3 Optimization level doesn't change the behavior (from -O0 to +O3). pubring.pgp contains all the keys on the servers, plus a few unpublished keys and some additional signatures. When an existing signature is replaced by a newer one by the same signator, memory gets corrupted. On my system, this results in a program abort. The problem is in file keyadd.c, function mergesigs(). When a signature is (possibly) going to be replaced, user_from_keyID() is called to get a pointer to the signator's user ID (as a C string in the in-memory user hash table. Then that pointer is passed to check_key_sig(), which passes it to getpublickey(), which passes it to readpublickey(), which reads successive user ID strings into it while it searches for the desired keyID. But the hash table contains dynamically allocated strings that are only as long as the string they hold. So when a longer user ID is read into it, memory past the end of the C string is corrupted. That trashes a hash table entry ("struct hashent"), destroying pointers and resulting in an illegal memory access later in the program. The offending code in mergesigs() only gets executed when a signature is being replaced with a more recent one by the same signator. It only showed up because I updated my pubring with all new keys on the servers for the last 31 days, and one key has an updated sig on it: pub 1024/AB1F4831 1993/05/10 Robert Walking-Owl <rrothenb(a)ic.sunysb.edu> Robert Walking-Owl <robert.rothenburg(a)asb.com> Here's a context diff for the fix. The signator userid isn't needed by check_key_sig() or the functions it calls since the signator's keyID is given, and if the userid is NULL then readkeypacket() ignores it, so just pass NULL to check_key_sig() and use the signator C string in mergesigs() as-is. Jim Castleberry - - cut here ------------------------------------------------------------------- *** old/keyadd.c Wed Oct 5 20:48:11 1994 - --- keyadd.c Wed Feb 15 22:37:53 1995 *************** *** 196,206 **** status = check_key_sig(fring, KeyIDpos, KeyIDlen, userid, fkey, keypos, ! ringfile, signator, (byte *) & xstamp, &sigClass); PascalToC(userid); - - PascalToC(signator); if (!status) { fprintf(pgpout, LANG("Replacing signature from %s\n"), - --- 196,205 ---- status = check_key_sig(fring, KeyIDpos, KeyIDlen, userid, fkey, keypos, ! ringfile, NULL, (byte *) & xstamp, &sigClass); PascalToC(userid); if (!status) { fprintf(pgpout, LANG("Replacing signature from %s\n"), -----BEGIN PGP SIGNATURE----- Version: 2.6.2 iQEVAwUBMJZkDJYkAuN55UFhAQG8aQf/bsx7xlS9P9SBE8ysMEbjMkKwdf6yZSCt fd0xBsUbTIsIS2Gzlx0ux7N3HWqJm/og2EBqebhfEzQk9IUBK8sp8Kbv8GtbUWrj ai2b6/hxu2yXbtQEAmTDJLO3fQCZ6yjkydFYaz2n+HuRxN4h6TlWwIHzQWOBCxuK qzPENr+c4YgMCHMVLGnAHDgPA8G9J/xX3UIPKQJQnrpAJwlGf+LTOkWeA+/kMLiw aos108n6698mcsIxXzHltCVlCaYYY6meFMHzD4rGjXOCURTtKTSRx1dJ7WNSn+1N JNwJSnFXrsvJRodko0fjpYnCUDNEbmEQgDsJX80wTdDfI+JH2LM/+g== =jh+s -----END PGP SIGNATURE-----

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ecash remailer
by sameer 17 Dec '03

17 Dec '03

To provide payee anonymity: Enterprising cypherpunk, Ed sets up the Ecash Remailer. Alice pays Bob e$15. Alice is anonymous. Bob sends Ed the e$15 Ed cashes the e$ into his ecash mint account, withdraws e$13.50 then pays Bob those e$14 .. Bob can now spend those e$ at will. Bob is now anonymous. This requires some trust-in-Ed, but Bob could be anonymous from Ed just as Ed is anonymous. Perhaps this is the scheme lucky mentioned. I will have to get an account and implement it. -- 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(a)c2.org

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