- cypherpunks-legacy@lists.ogf.org

Sound bite (a bit crude)
by Douglas Barnes 20 Apr '93

20 Apr '93

Came up during brainstorm session for article: "Clipper Chip Encryption: A leaky condom for the masses?" -- Doug (gumby(a)wixer.bga.com)

1 0

Is 40 bits too little?
by Hal 20 Apr '93

20 Apr '93

Just to remind everyone, the clipper key is not 40 bits. It is 80 bits. It is not divided up into two 40-bit halves. It is the result of xor'ing two 80-bit numbers, each of which would be held separately. Knowing one of the numbers would not improve your chances of guessing the key. Hal

1 0

Re: Is 40 bits too little?
by wcs＠anchor.ho.att.com 20 Apr '93

20 Apr '93

h Yes, 40 bits would be too little, especially since you can probably tell if you've got the correct key by the form of the data, but they're actually generating your 80-bit key as the XOR of two other 80-bit numbers, and searching 2**80 still takes reasonably long. Unfortunately, the method of generating the two 80-bit numbers is disturbingly suspect; see articles in sci.crypt and alt.privacy.clipper posted by Steve Bellovin and somebody with email from Martin Hellman and Dorothy Denning. Bill Stewart

1 0

Is 40 bits too little?
by Alexander Chislenko 20 Apr '93

20 Apr '93

Yes, in just a trillion iterations you can test all possible keys. But if for testing *each* key you will have to figure out whether a text /signal you produced represents sensible speech... - it may be prohibitively expensive. Alex Chislenko.

2 1

Sound Bite
by uni＠acs.bu.edu 20 Apr '93

20 Apr '93

"Giving the government keys to your encrypted messages is like giving them keys to the front door of your house." + "and accepting the promise, we'll only use them with proper authority."

2 1

Re: True Randoms
by tcmay＠netcom.com 20 Apr '93

20 Apr '93

William Kinney writes: >A little nuclear physics anyone? > >Seems like one real bitch with roll-your-own cryptography is the >scarcity of good random numbers to work with. I've read about various >schemes using I/O buffers, or keystroke timing like PGP does (even >there, true randoms are referred to as "precious"). > >So I thought a bit about how one could construct a true random generating >box. Went out to Sears and bought a $7 smoke detector, a "Family Gard" > >Does anyone see a real need for something like this? >Any hardware jocks out there who could lend some expertise? What follows is my standard "alpha particles as sources of random numbers" posting, which I have forwarded to the list a couple of times. (I'm not being at all critical of William Kinney for raising the issue again.) Quick summary: thermal noise in a back-biased diode is easier to get, has more bandwidth, doesn't have safety concerns, and is readily buildable. From: tcmay (Timothy C. May) Message-Id: <9210260530.AA00679(a)netcom2.netcom.com> Subject: Alpha Particles and One Time Pads To: cypherpunks(a)toad.com Date: Sun, 25 Oct 92 22:30:54 PDT Cc: tcmay (Timothy C. May) X-Mailer: ELM [version 2.3 PL11] Fellow Cypherpunks, Here's a posting I just sent to sci.crypt, dealing with using alpha particle sources as noise sources for generating one-time pads. Ordinarily I wouldn't bother you folks with this, especially since you're all reading sci.crypt (aren't you? Only the FidoNetters have a good excuse not to.). But this thread ties together two aspects of my life, cryptography and alpha particle errors in chips. --Tim Newsgroups: sci.crypt Path: netcom.com!tcmay From: tcmay(a)netcom.com (Timothy C. May) Subject: Re: Hardware random number generators compatible with PCs? Message-ID: <1992Oct26.051612.29869(a)netcom.com> Organization: Netcom - Online Communication Services (408 241-9760 guest) X-Newsreader: Tin 1.1 PL5 References: <1992Oct25.224554.1853(a)fasttech.com> Date: Mon, 26 Oct 1992 05:16:12 GMT Bohdan Tashchuk (zeke(a)fasttech.com) wrote: : The recent post on building a random number generator using a zener diode got : me to thinking once again about commercial alternatives. : : I haven't seen any commercial alternatives discussed here recently. And since : the market is so specialized, they may well exist but I'm simply not aware of : them. : : The ideal product would have the following features: : : * cost less than $100 : * use a radioactive Alpha ray emitter as the source It's a small world! In my earlier incarnation as a physicist for Intel, I discovered the alpha particle "soft error" effect in memory chips. By 1976 chips, especially dynamic RAMs, were storing less than half a million electrons as the difference between a "1" and a "0". A several MeV alpha could generate more than a million electron-hole pairs, thus flipping some bits. (Obviously the effect of alphas on particle detectors was known, and smoke detectors were in wide use, but nobody prior to 1977 knew that memory bits could be flipped by alphas, coming from uranium and thorium in the package materials. It's a long story, so I won't say any more about it here.) : * connect to an IBM PC serial or parallel port : * be "dongle" sized, ie be able to plug directly onto the port, and : not have a cable from an external box to the port : * be powered directly from the port : * generate at least 1000 "highly random" bits per second This should be feasible by placing a small (sub-microcurie) amount of Americium-241 on a small DRAM chip that is known to be alpha-sensitive (and not all of them are, due to processing tricks). Errors would occur at random intervals, depending on which bits got hit. Getting 1000 errors a second would be tough, though, as such high intensities would also tend to eventually destroy the chip (through longterm damage to the silicon, threshold voltage shifts, etc.). If you really want to pursue this seriously, I can help with the calculations, etc. : Details: : : Certainly in high volume these things can be made cheaply. Smoke detectors : often sell for under $10, and have a radioactive source, an IC, a case, etc. Yes, but smoke detectors use ionization in a chamber (the smoke from a fire makes ionization easier). That is, no real ICs. But ICs, and even RAM chips, are cheap, so your $10 figure is almost certainly in the ballpark. A bigger concern is safety, or the _perceived_ safety. Smoke detectors have, I understand, moved away from alpha particle-based detectors to photoelectric detectors (smoke obscures beam of light). Don't underestimate the public's fear of radioactivity, even at low levels. : Using a well-designed circuit based on Alpha decay should mean that the : randomness is pretty darn good. But not necessarily any better than noise from a Zener. With the higher bit rate from diode noise, more statistical tricks can be done. The relatively low bit rate from alpha decay gives less flexibility. On the other hand, alpha hits are undeniably quite random, with essentially no way to skew the odds (unlike with diode noise). : Everyone these days has either a serial or parallel port available, either : directly or thru a switch box. : : The tiny "dongle" size is a convenience. If it is small and powered directly : from the port, there are no cables to get in the way. There is enough power : available from the signal lines on these ports to power simple devices. E.g. : most mice don't require an external power supply. : : For most applications 1000 bits per second should be adequate. For example, : it would be quite adequate for session keys. For generating pseudo : one-time-pads, an overnight run should generate plenty of values. Continuously : generating values for a month would produce about 300 MB, which should be : enough to exchange new CD-ROM key disks once a month. One time pads are complicated to use. Only very high security applications that can also afford them use them. For example, some diplomatic traffic. I can't conceive of a case where 300 MB a month could be used. And _theft_ (or copying) of the CD-ROM one time pads has got to be a much bigger issue that whether alpha particle noise sources are better than diode noise sources! By about 10 orders of magnitude I would say. Black bag jobs on the sites holding the keys will be the likeliest attack, not trying to analyze how random the noise is (even a fairly crummy noise source will not yield enough information to a cryptanalyst trying to break a one-time pad). Having said all this, I'm glad you gave some thought to alphas. For a time in the late 1970s this was the chip industry's number one headache...it was definitely the most exciting time of my life. --Tim -- .......................................................................... Timothy C. May | Crypto Anarchy: encryption, digital money, tcmay(a)netcom.com | anonymous networks, digital pseudonyms, zero 408-688-5409 | knowledge, reputations, information markets, W.A.S.T.E.: Aptos, CA | black markets, collapse of governments. Higher Power: 2^756839 | PGP 2.0 and MailSafe keys by arrangement.

1 0

Sound bite time
by peb＠PROCASE.COM 20 Apr '93

20 Apr '93

Okay, here are my sound bytes: 1. The long one (needed when they try to outlaw encryption): As we move into the electronic frontier, the freedom to use crypto-privacy technology is becoming the equivalent to the right to bear arms: it is the last line of defense against a tyrannic government. The good news is that privacy is a defensive technology, not an offensive one. Giving up this un-enumerated right could be disasterous to future generations. 2. The short one (simple-minded Clipper is no good): Crypto Privacy is like a bullet proof vest for your transmitted speech; the Clipper chip is a paper jacket with extra zippers in the back. Paul E. Baclace peb(a)procase.com

2 1

Subscribe me
by Kang Meng Chow 20 Apr '93

20 Apr '93

SUBSCRIBE ME

1 0

The Wing-Clipper
by fnerd＠smds.com 20 Apr '93

20 Apr '93

> Matthew Lyle (214) 888-0474 > OpenConnect Systems matt(a)oc.com > Dallas, TX > > "...and once you have tasted flight, you will walk the earth with your > eyes turned skyward, for there you have been, and there you long > to return..." It's the Wing-Clipper chip. Great emblem: a bald eagle with its wings clipped. -fnerd quote me

1 0

Re: Mailing list name
by peb＠PROCASE.COM 20 Apr '93

20 Apr '93

I vote for cryptoprivacy because it is more appropriate, and due to recent events, it helps to be clear about these things when the media gets involved. Examples: 1. The infamous CBS coverage of the Hacker's Conference that turned "Cracker" Conference in the nightly news regardless of what the reporters were told. 2. Notice how the NIST press release said ``This system is more secure than many other voice encryption systems readily available today. [^^^^^^^^^^^^^^^^^^^^^^ not claiming the best] While the algorithm will remain classified to protect the security of the key escrow.'' but the Knight-Ridder translated this into: ``...National Security Agency invented a new coding device, called the "Clipper Chip," which is said to be much harder to crack than encoding systems now on the market. Now the wiretap chip sounds better than any equipment on the market rather than "better than many" which is a very weak claim. Happens all the time. Information must be very clear. Punk isn't the right word. Paul E. Baclace peb(a)procase.com

1 0