December 2003 - cypherpunks-legacy

Generating random numbers from english text
by baldwin＠LAT.COM 17 Dec '03

17 Dec '03

Hello, With the current random number discussion going on, I thought I would point out one convenient way to generate random numbers in the situation where you do not need to generate them frequently. I believe that Claude Shannon (Dr. Information Theory) proposed this: 1. Ask a person to speak about any topic for a paragraph or two. Instruct them to generate original sentences, not just repeats of some passage of a written work. Write down what they say. 2. The english language has an entropy of 1.0 to 1.5 bits per letter, so it is safe to extract one bit per character. If you read Shannon's work and its modern interpretation, you will understand that this bit per character is truely random. It is uncorrelated with all the other bits. The reason for avoiding a pre-existing written work (poem, article, story, etc), is to avoid a brute force search of the source language space. The modern version of this algorithm, is to compute the MD5 digest of a long text string. For a 128 bit digest, you need at least 128 characters of source language. For a larger random number, you can concatenate multiple MD5 values from multiple pieces of source text. If the random numbers form the basis of crypto keys, then it is important to make sure no one can uncover the original source text. --Bob

1 0

Re: Spread-spectrum net (vulnerability of)
by doug＠netcom.com 17 Dec '03

17 Dec '03

Matthew J Ghio <mg5n+(a)andrew.cmu.edu> said: >Switching frequencies rapidly to prevent triangulation is still the best >defense. Think from the point of view of the spotters. They can look at a broad-spectrum scan, gradually eliminate known sources, and end up homing in on the remaining high power signals. Doug

2 1

Re: Generating random numbers from english text
by nobody＠alumni.cco.caltech.edu 17 Dec '03

17 Dec '03

On Thu, 14 Oct 93 09:29:16 PDT., baldwin(a)LAT.COM (Bob Baldwin) writes: < With the current random number discussion going on, I thought < I would point out one convenient way to generate random numbers in < the situation where you do not need to generate them frequently. I believe < that Claude Shannon (Dr. Information Theory) proposed this: < < 1. Ask a person to speak about any topic for a paragraph or two. < Instruct them to generate original sentences, not just repeats of < some passage of a written work. Write down what they say. < < 2. The english language has an entropy of 1.0 to 1.5 bits per letter, < so it is safe to extract one bit per character. If you read Shannon's < work and its modern interpretation, you will understand that this < bit per character is truely random. It is uncorrelated with all < the other bits. The reason for avoiding a pre-existing written < work (poem, article, story, etc), is to avoid a brute force search < of the source language space. can you provide a citation? i recently read a paper Shannon wrote [1] on a study of randomness in english text, and this is definitely not the impression i got from it. in this study Shannon demonstrates that english-speaking humans are very capable of predicting the next letter of an unknown text given the letters up to that point (he also shows this for the reverse direction; that is, starting at the end of the text and working forward, subjects were almost as capable of predicting correctly as they were starting from the front of the text). this seems to imply that there is some non-random relationship (statistical or otherwise) among the letters in a text. might this redundancy be carried over into any encoding (MD5 hash, e.g.) of the text? theoretically, at least, this may compare to Vigne're ciphers; the key is based on some text other than the plaintext. < The modern version of this algorithm, is to compute the < MD5 digest of a long text string. For a 128 bit digest, you need < at least 128 characters of source language. For a larger random number, < you can concatenate multiple MD5 values from multiple pieces of source text. could someone here describe how this compares to other pseudo-random sources? how well would this function as a seed to some other pseudo-random number generation process? [1] Shannon, Claude E., "Prediction and Entropy of Printed English," Bell System Technical Journal, vol. XXX, No. 1, Jan. 1951, pp. 50-64.

1 0

notes on Gejdenson's House hearing on mass-mkt. crypto export ctrls.
by Stanton McCandlish 17 Dec '03

17 Dec '03

I have a document, described in the subject line, by EFF's Danny Weitzner If you'd like this posted (it's about 100 lines) let me know. It's FTPable at ftp.eff.org, /pub/eff/Temp, gejcrypt.exp -- Stanton McCandlish Electronic Frontier Foundation Online Activist & SysOp "A nation that is afraid to let its people judge the truth and falsehood of ideas in an open market is a nation that is afraid of its people." -JFK -=> mech(a)eff.org NitV-DC BBS 202-232-2715, Fido 1:109/? IndraNet 369:111/1

1 0

SADF
by Matthew J Miszewski 17 Dec '03

17 Dec '03

Scott, While the timing of the -kg keystrokes is 'more' pseudo-random (heh.) than is the obviously repititive nature of your first post you do bring up a valid concern that Im sure someone of the many PRNG people on the list can, and will answer. This particularly ties in with the thread coming in from the previous poster whom refered to the new pgp23a process of -kg. I would think that my typing while entering my pass phrase is *definitely* less random than when I am consciously aware that I am generating a key. (This very awareness of course makes the randomness less random, ugh! where is chaos when you need/want it?) --Matt ______________________________________________________________________________ "This new technology (the printing press) threatened the Crown, which shuddered at the thought of widespread dissemination of works advocating religious heresy and political upheaval. The Crown's solution to the problem was a system of regulation designed to control this "dangerous" art." -From my Copyright Law Text (refrencing the Statute of Anne - the first Copyright Statute) (c)1993 ______________________/___________________________________mjmiski(a)macc.wisc.edu

1 0

Re: Secret network
by swc＠uc1.ucsu.edu 17 Dec '03

17 Dec '03

Alas, water pipes are much better for 1) noise and unintentional transmissions (which can be quite garbled and no one cares), and 2) low frequency transmissions (which can carry only low bandwidth communications). Trying to transmit meaningful communications at high data rates over water pipes would be a TREMENDOUS technical challenge, requiring a vast amount of signal processing to compensate for multipath reflections, impedance mismatches, thermal noise, pickup of an almost variety of interference soures ces, infinite variety of interference sources. , nonstationary channel characteristics, intermittent grounds, etc etc ad infinitum (or at least ad nauseam). Sorry about the cold water, I have seriously considered this scheme and believe that it can be used only for very short haul, very low bandwidth communications (say intra-building at 300 baud). , although that's a guess not a simulation result). ------------------------------------------------------------------------ Stuart W. Card, Consultant, Card & Associates -- Research & Development Box 153 RR 1 Newport Rd Utica NY 13502 315-735-1717 / FAX -8469 swc(a)uc1.ucsu.edu or cards(a)top.cis.syr.edu "Who is John Galt?"

2 1

Glithces in PGP Message
by Matthew J Miszewski 17 Dec '03

17 Dec '03

Ummm... Thats not a PGP message ya got thare, but rather someone who likes to type gibberish and send it as a message. Look at your keyboard and then look at the message. Now keep your hands in the normal position and type random (pseudo) keys. Hmm...I tend to hit 'sadf' an awful lot too. --Matt ______________________________________________________________________________ "This new technology (the printing press) threatened the Crown, which shuddered at the thought of widespread dissemination of works advocating religious heresy and political upheaval. The Crown's solution to the problem was a system of regulation designed to control this "dangerous" art." -From my Copyright Law Text (refrencing the Statute of Anne - the first Copyright Statute) (c)1993 ______________________/___________________________________mjmiski(a)macc.wisc.edu

1 0

Re: DES
by Joe Thomas 17 Dec '03

17 Dec '03

> > 2) How much longer would it take to break triple DES versus standard DES > > using one of the key-breaking machines described? > > Using brute force, it would take the cube of the > time it takes to break single DES. Hmm... I can't figure out what it would mean to cube time. For two-key (112 bit) triple DES, it should be 2^56 times longer to exhaustively search the keyspace, with three keys, 2^112 times longer. This assumes the keysearch engine is pipelined, so each trial encryption takes the same amount of time, despite the additional rounds. Such a machine would cost more, of course, since it would have a longer pipeline, but wouldn't otherwise be significantly different in design. Back-of-the-envelope calculation: a design like the "7-hour exhaustive keysearch" engine for 2-key triple DES would take 50 trillion years or so to exhaust the keyspace. That's for a cost on the order of $1 million (it should be buildable for less than three times the cost of the 56-bit key version). Seems secure, but as Perry says, > Whether a more sophisticated techinque is possible is unknown. Joe

2 1

Re: PK patents
by whitfield.diffie＠Eng.Sun.COM 17 Dec '03

17 Dec '03

> I forget if your name is on any patents. My name is on the exponential key exchange patent (4,200,770). I wasn't much involved in the filing process and the for all that it pays me royalties and is of commercial significance, I didn't pay a lot of attention to it. I can believe someone might write an entertaining article called the ``The Public Key Patent Squabble,'' but I have no interest at all in doing so. What exactly do you think I should have included? > I understand that the NSA tried to deny the RSA patent . . . > Do you know anything about what I'm talking about? No. But after all, the RSA patent was filed from MIT by people (R, S, and A) that I didn't know well till much later. There may have been some hankey pankey I didn't know about, but I certainly don't recall the New York Times article you refer to. The statement that ``They just got the application back rejected.'' Doesn't sound right to me. I presume that the Patent Office has to state why an application is returned. It's decisions, after all, are a constant subject of litigation and it must have to be very careful about following its own procedures. There was an interference between the RSA patent and the Pohlig-Hellman patent, which is the reason RSA didn't issue till '83. > I'm very concerned about some anomalies on the cypherpunk list. > Are you on it? Yes. Is that irregular or are you referring to something I haven't noticed? > In particular some messages you may have traded with T.C. May have > shown up lately and I'm a bit suspicious of some irregularities. That's because, as discussed one of Tim's messages yesterday, I normally send comments only to the people who posted and leave it to them to repost to the whole list if they think what I said is worthwhile. Like Tim, I have noticed that the list is cluttered with multiple responses to the same question. Whit

1 0

Reason Magazine Nov 1993
by wak＠next0.math.pitt.edu 17 Dec '03

17 Dec '03

Cypherpunks and Extropians, I'd like to mention that the Nov 1993 issue of Reason ("Free Minds and Free Markets") magazine has an article addressing the issue of electronic privacy by Lee Dembart entitled "Hide and Peek". Walter A. Kehowski wak(a)next0.math.pitt.edu

1 0