Cryptography-Digest Digest #551, Volume #10 Fri, 12 Nov 99 12:13:03 EST
Contents:
Re: What's gpg? <PHILOSOPHY 101> ("Douglas A. Gwyn")
Re: Proposal: Inexpensive Method of "True Random Data" Generation (Randy Poe)
Re: ENCRYPTOR 4.0 by Comotex USA Inc. CRACKED !! ("ME")
Need technique for about 24 bytes (Caesar Valenti)
Re: Can the SETI@home client be protected? (Guy Macon)
Re: Lenstra on key sizes (fungus)
Re: Ultimate Crypto Protection? ("Tim Wood")
Re: Ultimate Crypto Protection? ("Gary")
Re: Build your own one-on-one compressor (Tim Tyler)
Re: Signals From Intelligent Space Aliens? Forget About It. (SCOTT19U.ZIP_GUY)
Re: What sort of noise should encrypted stuff look like?
Re: What sort of noise should encrypted stuff look like?
Re: smartcard idea? (Jean-Jacques Quisquater)
Re: Can the SETI@home client be protected? (fungus)
Re: Proposal: Inexpensive Method of "True Random Data" Generation ("Trevor Jackson,
III")
Re: Proposal: Inexpensive Method of "True Random Data" Generation ("james d. hunter")
Re: Proposal: Inexpensive Method of "True Random Data" Generation ("Trevor Jackson,
III")
Re: Build your own one-on-one compressor (Mok-Kong Shen)
Re: real random number generator idea -- any criticisms? (Boaz Lopez)
Re: Proposal: Inexpensive Method of "True Random Data" Generation ("Trevor Jackson,
III")
----------------------------------------------------------------------------
From: "Douglas A. Gwyn" <[EMAIL PROTECTED]>
Subject: Re: What's gpg? <PHILOSOPHY 101>
Date: Fri, 12 Nov 1999 05:25:40 GMT
[EMAIL PROTECTED] wrote:
> Each cracking attempt indeed is based on the experience gained from the
> previous failures; I think there is a shaky kind of validity for saying
> that "this cipher hasn't been cracked after five years of study, so, on
> the average, it should have another five years before it is cracked".
Again, you're assuming a statistical model that simply doesn't fit.
For example, a master cryptanalyst upon reading the above might decide
to immediately demonstrate a crack of that system. Or, if the system
is truly uncrackable, the 5-year span measures nothing that is
characteristic of the system itself.
> Not every statistician accepts the validity of Bayesian statistics
> precisely because it attempts to deal with the case when things
> _aren't_ neatly drawn from a population.
So-called Bayesian methods clearly are valid, if properly applied
(there's the catch). They have been used since around 1940 in real
cryptanalysis, and they work. The most reasonable objections some
statisticians have had were based on the apparent need to estimate
priors; but applying Bayes' rule is a stable process, resulting in
less uncertainty than one starts with. Also, quite often all that
is needed is a likelihood ratio (in order to make a rational choice
among alternatives), and that can often be computed without priors.
------------------------------
From: [EMAIL PROTECTED] (Randy Poe)
Crossposted-To: sci.math,sci.misc,sci.physics
Subject: Re: Proposal: Inexpensive Method of "True Random Data" Generation
Date: Fri, 12 Nov 1999 06:46:44 GMT
On 11 Nov 1999 19:44:48 GMT, [EMAIL PROTECTED]
(Mike McCarty) wrote:
>In article <[EMAIL PROTECTED]>, Coen Visser <[EMAIL PROTECTED]> wrote:
>)
>)I agree that the bickering about randomness of strings of size 1
>)is a waste of time or at best purely academic. But there is a *lot*
>)of (statistical) information in a random string of size ~ 2E1024 whether
>)you look at it as a single string or as 2E512 strings of size 2E512.
>
>The length of the string is irrelevant. If you had 2e512 strings, then
>you could draw conclusions. But from one string, of whatever length, one
>cannot draw a conclusion.
>
Limiting to binary strings:
I can calculate whether 1's and 0's occur with equal frequency.
In fact I can calculate the distribution of strings of any size up to
2E1024.
I can calculate to what extent the n-th bit/substring is correlated
with the (n+m)-th bit/substring.
I can decide whether those properties of the string are suitable or
not for the application of this particular pseudo-random string to my
application.
Those seem to me like plenty of conclusions to draw from a single
string.
- Randy
------------------------------
From: "ME" <[EMAIL PROTECTED]>
Subject: Re: ENCRYPTOR 4.0 by Comotex USA Inc. CRACKED !!
Date: Fri, 12 Nov 1999 18:44:55 +1100
>Word 6.0, I think you'll find, uses a weaker encryption algorithm.
Word 2 and 6 basically used a password XOR'ed with a constant string and a
length value to form a 16 byte string, which is then repeatedly XOR'ed with
the plain text.
I found encrypting a long string of 000... then 11111... in several files
showed the 16 byte XOR pattern.
Obviously this product and Word 6 both fall to simple frequency analysis.
Lyal
------------------------------
From: Caesar Valenti <[EMAIL PROTECTED]>
Subject: Need technique for about 24 bytes
Date: Fri, 12 Nov 1999 00:06:33 -0800
I am in need of finding source code that will encode (and decode, of
course) a string of about 24 characters. Out of necessity, the string
will only consist of the 36 alpha numeric characters (case insensitive)
The encrypted string is also limited to the same 36 characters. The
encrypted string should be about the same size as the original.
The code should relatively short and easy to implement. Security is a
moderate concern; however I can accept 99.99% security for the general
population (in this group, probably more like 20%!).
I know this is a newbie question. I am extremely new to this, so be
gentle. I will be getting a copy of Applied Cryptology this weekend,
and will review it. Any ideas? Possibly RC4? XOR? or???
Thanks
CV
------------------------------
From: [EMAIL PROTECTED] (Guy Macon)
Subject: Re: Can the SETI@home client be protected?
Date: 12 Nov 1999 00:25:40 PST
In article <[EMAIL PROTECTED]>, [EMAIL PROTECTED]
(fungus) wrote:
>Good luck in getting all the clients to upgrade their software
>to use the new protocols...
>
>
>...and if you don't force *everybody* to upgrade then the hackers
>will just use the older versions of the software.
Already fixed. They can send a text box to your screen with the
work unuit. They make you click OK on a warning for a mont or so
(or unti you upgrade0, then they stop sending workunits to old clients.
------------------------------
From: fungus <[EMAIL PROTECTED]>
Subject: Re: Lenstra on key sizes
Date: Thu, 11 Nov 1999 21:48:44 +0100
Bill McGonigle wrote:
>
> In article <80d67o$jju$[EMAIL PROTECTED]>, [EMAIL PROTECTED]
> (SCOTT19U.ZIP_GUY) wrote:
>
> > And have contests they
> > can't do becasue of inherint weaknesses in there short keyed methods.
>
> I'm not familiar with your product, but a long key does not make a secure
> product. A longer key can make a more secure product.
>
Welcome on board, and a hearty "well said".
PS: I advise you to check deja.com before entering into any lengthy
correspondence with dscott.
--
<\___/>
/ O O \
\_____/ FTB.
------------------------------
From: "Tim Wood" <[EMAIL PROTECTED]>
Subject: Re: Ultimate Crypto Protection?
Date: Fri, 12 Nov 1999 10:38:57 -0600
Gary wrote in message <80fhd0$sve$[EMAIL PROTECTED]>...
>
>In the old days an OTP was a page from a book etc. not from a PRNG.
>(eg In the very old Beale Cipher the constitution was the OTP.)
>
>Two different pages from two different books would be a nightmare to find.
>As I guess the NSA were looking for the book pages.
A PRNG is not a OTP and never will be due to the P ;-)
Tim
------------------------------
From: "Gary" <[EMAIL PROTECTED]>
Subject: Re: Ultimate Crypto Protection?
Date: Fri, 12 Nov 1999 12:33:59 -0000
Tim Wood wrote in message <80gqkr$2g4$[EMAIL PROTECTED]>...
>
>Gary wrote in message <80fhd0$sve$[EMAIL PROTECTED]>...
>A PRNG is not a OTP and never will be due to the P ;-)
Sorry you're right, that should be a true random source.
Still in the old days OTP was a page from a book and not a truly random
source.
------------------------------
Crossposted-To: comp.compression
From: Tim Tyler <[EMAIL PROTECTED]>
Subject: Re: Build your own one-on-one compressor
Reply-To: [EMAIL PROTECTED]
Date: Fri, 12 Nov 1999 12:53:20 GMT
In sci.crypt Mok-Kong Shen <[EMAIL PROTECTED]> wrote:
: Tim Tyler wrote:
:> Will the 65536 words in your dictionary contain all the words I used?
: [...] My humble opinion about that issue is: (1)
: One has to be a very learned man to write ordinary texts that
: contains plenty of words outside a dictionary of that size.
I don't know. This very message contains the number 65536. *That*
won't be in the dictionary. Nor will 'phone numbers, email addresses,
URLs, or many proper names...
: (2) If words outside the dictionary are rare, then the effect on
: compression of these is negligible (one uses a verbatim copying
: method for these words).
I have a problem with this point.
So far the only 1-1 scheme I have seen involves mapping every symbol to a
corresponding 16-bit word.
No scheme has been presented that uses this 16-bit scheme, and allows for
verbatim copying of text without doubling its size, while retaining the 1-1
property.
My original system allows vertabim copying of text - but this involves
restrictions being placed on the allowed dictionary entries.
:> I think the scheme you are proposing can compress English texts. I doubt it
:> will be as good as methods allowing variable-length symbols, and schemes like
:> arithmetic coding which allow symbols which are not an integral number of bits
:> in length.
: Of course, without some extensive experiments neither your doubt
: nor my claim can be ascertained.
Hopefully some experimentation will reveal how practical the scheme is.
--
__________
|im |yler The Mandala Centre http://www.mandala.co.uk/ [EMAIL PROTECTED]
The internet is full, go away.
------------------------------
From: [EMAIL PROTECTED] (SCOTT19U.ZIP_GUY)
Subject: Re: Signals From Intelligent Space Aliens? Forget About It.
Date: Fri, 12 Nov 1999 14:03:10 GMT
In article <80ghpg$[EMAIL PROTECTED]>, "Juergen Nieveler / CompuNet"
<[EMAIL PROTECTED]> wrote:
>SCOTT19U.ZIP_GUY <[EMAIL PROTECTED]> schrieb in im Newsbeitrag:
>80g2nc$vgg$[EMAIL PROTECTED]
>
><SNIP>
>>
>> Sorry sir but I always got A's in physics. I may have only got
>> in the 17 percentile for english crap but math and science was
>> alwyas 99+ percentile. The appeant mass incerse you see
>> is only to an observer who is looking at it from a different frame
>> of reference. To some one in a rocket slowy accelerating there
>> would be no change in appeatant mss. Try again next time.
>>
>
>Sorry, I´m not as good at physics as you... but the acceleration effect
>stays the same, doesn´t it?
>
>How long would it actually take (for somebody IN the spaceship) to
>accelerate to light speed, given a constant 6G acceleration (and even that
>might be a bit uncomfortable for the poor astronaut...)?
>
The problem with the question is that it is not really valid. Since
acceleration to a travler is no more different than gravity. Yes it has
units of length/(times squared) but as one is accelrating from the
obeserver on earth. He would appear to gain mass and he would
appear to get shorter in length and his clock would appear to run
at a slower time but he would never get to the speed of light. That
is way they call it relativity my friend. You have to think of it
in terms like this. Light is always traveling at the speed "c" in
outer space. But to each observer light as measured by them
is always "c" so one is always looking at the other frame
and distorting ones view of it by shoving in terms of the
from square root ( one - ( velocity squared)/(speed of light squared))
you adjust what you think the others clock rate and mass and distance
in certain direction to always keep light at the same speed.
If you don't belive blame Einstein not me.
You never get to the speed of light according to Einstein. However
some think you can cheat it by tunneling through it but that is
beyond most excepted theories at this point.
David A. Scott
--
SCOTT19U.ZIP NOW AVAILABLE WORLD WIDE
http://www.jim.com/jamesd/Kong/scott19u.zip
Scott famous encryption website NOT FOR WIMPS
http://members.xoom.com/ecil/index.htm
Scott rejected paper for the ACM
http://members.xoom.com/ecil/dspaper.htm
Scott famous Compression Page WIMPS allowed
http://members.xoom.com/ecil/compress.htm
**NOTE EMAIL address is for SPAMERS***
------------------------------
From: [EMAIL PROTECTED] ()
Subject: Re: What sort of noise should encrypted stuff look like?
Date: 12 Nov 99 13:24:40 GMT
karl malbrain ([EMAIL PROTECTED]) wrote:
: Douglas A. Gwyn <[EMAIL PROTECTED]> wrote in message
: news:[EMAIL PROTECTED]...
: > Tom St Denis wrote:
: > > ... why do they call it white noise?].
: > White light consists of all colors of the visible spectrum with
: > approximately equal intensity. So when any spectrum consists of
: > all frequencies with approximately equal intensity, it is called
: > "white". The "noise" aspect should be obvious; if not, try
: > feeding it to an audio player and hear what it sounds like.
: No it's not obvious: the noise here is the difference between the THREE
: frequencies we can actually deal with in our eyes to determine WHITE as a
: subjective color, and ALL colors of the visible spectrum as an objective
: analysis. Karl M
It is true that our eyes have three types of photoreceptor.
The Sun, however, shines white sunlight down to the Earth without
reference to the design of our eyes, and a characteristic of that light is
that it has roughly equal intensities at all visible frequencies. The term
"white noise" actually applies, not to any kind of light, but to audio
signals (and, by extension, to radio and electrical signals) that have a
flat frequency distribution.
John Savard
------------------------------
From: [EMAIL PROTECTED] ()
Subject: Re: What sort of noise should encrypted stuff look like?
Date: 12 Nov 99 13:27:12 GMT
Douglas A. Gwyn ([EMAIL PROTECTED]) wrote:
: Lincoln Yeoh wrote:
: > Would this be likely to happen? Say I precompress something (say LZ
: > or huffman) and then encrypt it with DES. If I decrypt it with a
: > wrong key, what are the chances of the result not being white noise?
: If the compression scheme is well fitted to the source model, then
: uncompressing random noise will produce an output that adheres
: fairly closely to the source model.
That is correct. However, the result of decryption - before uncompression
is applied - with a wrong key is almost certain to be white noise; this
should be noted, as it might be the answer to the question.
John Savard
------------------------------
From: Jean-Jacques Quisquater <[EMAIL PROTECTED]>
Subject: Re: smartcard idea?
Date: Fri, 12 Nov 1999 14:55:42 +0100
See ...
http://www.gemplus.fr/smart/r_d/index.htm
------------------------------
From: fungus <[EMAIL PROTECTED]>
Subject: Re: Can the SETI@home client be protected?
Date: Fri, 12 Nov 1999 13:16:40 +0100
Guy Macon wrote:
>
> Some of you Cpypto Folks have dpone some distributed computing for
> cracking codes, haven't you? How did you deal with people who
> patch the client programs?
That was different. For the crypto challenges people had to write
their own clients anyway.
--
<\___/>
/ O O \
\_____/ FTB.
------------------------------
Date: Fri, 12 Nov 1999 09:48:57 -0500
From: "Trevor Jackson, III" <[EMAIL PROTECTED]>
Crossposted-To: sci.math,sci.misc,sci.physics
Subject: Re: Proposal: Inexpensive Method of "True Random Data" Generation
Randy Poe wrote:
> On 11 Nov 1999 19:44:48 GMT, [EMAIL PROTECTED]
> (Mike McCarty) wrote:
>
> >In article <[EMAIL PROTECTED]>, Coen Visser <[EMAIL PROTECTED]> wrote:
> >)
> >)I agree that the bickering about randomness of strings of size 1
> >)is a waste of time or at best purely academic. But there is a *lot*
> >)of (statistical) information in a random string of size ~ 2E1024 whether
> >)you look at it as a single string or as 2E512 strings of size 2E512.
> >
> >The length of the string is irrelevant. If you had 2e512 strings, then
> >you could draw conclusions. But from one string, of whatever length, one
> >cannot draw a conclusion.
> >
>
> Limiting to binary strings:
> I can calculate whether 1's and 0's occur with equal frequency.
> In fact I can calculate the distribution of strings of any size up to
> 2E1024.
> I can calculate to what extent the n-th bit/substring is correlated
> with the (n+m)-th bit/substring.
> I can decide whether those properties of the string are suitable or
> not for the application of this particular pseudo-random string to my
> application.
>
> Those seem to me like plenty of conclusions to draw from a single
> string.
Those properties are all instrinsic to the string. Randomness is an extrinsic
property.
Note that none of the analysis you offered were probabalistic. None described
the population from which the string was selected. None described the
uncertainty or predictability of the string. None of them have anything to do
with the "randomness" of the string.
------------------------------
From: "james d. hunter" <[EMAIL PROTECTED]>
Crossposted-To: sci.math,sci.misc,sci.physics
Subject: Re: Proposal: Inexpensive Method of "True Random Data" Generation
Date: Fri, 12 Nov 1999 09:43:53 -0500
Reply-To: [EMAIL PROTECTED]
Coen Visser wrote:
>
> "james d. hunter" wrote:
>
> > I think you better define random first, before you discuss it.
>
> Sounds reasonable. I'll provide a few intuitive notions.
> Random, as in "this string looks random", has
> the intuitive meaning that we do not find any patterns in it.
> So the string "0101010101010101" does not look random because
> we find the repeating pattern "01". But "1010110001000110" does
> look random because we can not find a pattern. We can use the "01"
> pattern to compress the first string while we have no way to
> compress the second string.
The general guiding principles concerning "sounds" and "looks"
when connected with "random" are that Quantum Mechanics looks
and -is- a randomly generated theory of the universe.
>
> > "Random" only makes sense in terms of a random process.
>
> There is a strong connection between statistical tests and
> randomness of strings as defined by incompressibility.
> So I suspect there will be a link with random processes too,
> although I do not know of any theory about it.
Nobody really questions that well-defined string properties
are near perfect substitutes for "natural" random processes.
The only people who really use stuff like atomic decay
processes are the national defense applications and the
very highest level security. The reason it's mostly used
in those areas concerns actual -physical- integrity rather than
mathematical properties.
> > Strings are usually interpreted as -fixed- outputs of a
> > random process. "Incompressibility" has to do with the
information
> > content of the -fixed- string. There is nothing really "random"
about
> > it.
>
> A random string has maximum information content: its information
> can not be described by a smaller string. You can find "randomness"
in
> the fact that you need the complete string to get its information. No
> smaller
> string can contain as much information. If you are given everything
> but the n-th bit of a random bitstring you would not have enough
> information
> to say what value the missing bit would have.
If you insist on confusing yourself by using "random" for static and
dynamic properties, be my guest, it's not I like really care.
------------------------------
Date: Fri, 12 Nov 1999 09:55:11 -0500
From: "Trevor Jackson, III" <[EMAIL PROTECTED]>
Crossposted-To: sci.math,sci.misc,sci.physics
Subject: Re: Proposal: Inexpensive Method of "True Random Data" Generation
Coen Visser wrote:
> "Trevor Jackson, III" wrote:
>
> > Nope. You are vaccilating on the use of the term compression. previously you
>assumed
> > that you could compress any single string irrespective of the population from
>which it
> > was drawn. Now you are looking at the population statistics.
>
> That is a misunderstanding between us. I do not believe that one
> can compress any single string irrespective of the population
> from which it was drawn and never believed so. In fact I believe
> that most strings from the set of all finite strings are difficult
> to compress.
If you admit all finite strings there are no strings you can compress. Anything you
compress
will displace (inflate) the string originally represented by the compressed
representation.
I.e., you can only compress a subset of all finite strings at the expense of inflating
another
subset. Further, the sum of the new lengths of the strings in the two subsets will be
larger
than the sum of the old lengths.
Losing game.
>
>
> > My example was based on the your example os a single string being compressible.
>In fact
> > I have a TRNG that dumps data onto floppies. I have a ten megabit random string
>in my
> > shirt pocket. I've compressed ten megabits of randomness into "the string in
> > randseed.bin on the floppy in my shirt pocket", which is certainly a high
>compression
> > factor for lossless compression algorithms.
>
> > Note that the actual value of the string is irrelevant to this compression
>technique.
> > ANY string of ten millions bits can be encoded in a simlar way. Thus all strings
>are
> > compressible, and thus non-random, when your definition of compression is applied.
>
> I am not following you here due to the above mentioned misunderstanding.
>
> > > The connection between incompressibility of strings and randomness can
> > > be used *directly* to prove all kinds of mathematical properties. So I
> > > would say it is useful and meaningful. What can one do with "your"
> > > definition of (random) number generators?
>
> > Avoid mistakes.
>
> That sounds very useful. How would you use the definition and underlying
> theory to show that a RNG is not a TRNG?
Find some correlation in the behavior of the generator, predict its continued
appearance,
confirm the prediction by further testing, and conclude that, within the confidence of
the
test, the generator lacked randomness in at least the degree of correlation.
Note that inequality. I cannot ever prove that a generator has some floor of
randomness. I
can only prove that a generator has a ceiling on randomness.
------------------------------
From: Mok-Kong Shen <[EMAIL PROTECTED]>
Crossposted-To: comp.compression
Subject: Re: Build your own one-on-one compressor
Date: Fri, 12 Nov 1999 15:17:15 +0100
Tim Tyler wrote:
>
> In sci.crypt Mok-Kong Shen <[EMAIL PROTECTED]> wrote:
> : Tim Tyler wrote:
>
> :> Will the 65536 words in your dictionary contain all the words I used?
>
> : [...] My humble opinion about that issue is: (1)
> : One has to be a very learned man to write ordinary texts that
> : contains plenty of words outside a dictionary of that size.
>
> I don't know. This very message contains the number 65536. *That*
> won't be in the dictionary. Nor will 'phone numbers, email addresses,
> URLs, or many proper names...
For anything not in the dictionary, some escape mechanism must be
used. I am not offering optimal ways of doing that, since I am
not the person that is going to do the present design. Basically you
can switch to numberical mode, to verbatim copying mode, etc. etc.
and back. In the old days when 5-channel codes (in connection with
paper tapes) were used, one has two special codes to switch from one
interpretation mode to the other and back. The same principle can
be applied here. As I mentioned in another post, there are other
design problems with the dictionary scheme that also need to be solved
properly, namely the plurals of nouns, past participles of verbs
and captilization. It is a non-trivial task.
>
> : (2) If words outside the dictionary are rare, then the effect on
> : compression of these is negligible (one uses a verbatim copying
> : method for these words).
>
> I have a problem with this point.
>
> So far the only 1-1 scheme I have seen involves mapping every symbol to a
> corresponding 16-bit word.
>
> No scheme has been presented that uses this 16-bit scheme, and allows for
> verbatim copying of text without doubling its size, while retaining the 1-1
> property.
>
> My original system allows vertabim copying of text - but this involves
> restrictions being placed on the allowed dictionary entries.
Like the above, I am not offering an optimal solution. But one way
could be like this: send a code for verbatim begin then send
the bytes involved (padding to even number of bytes with a space,
if needed, thus two ASCII bytes have the same 'syntax' as any
code with 16 bits) then send a code for verbatim end. Of course,
it is assumed that one does not need that mechanism very often,
otherwise the compression could become an explosion.
M. K. Shen
------------------------------
From: Boaz Lopez <[EMAIL PROTECTED]>
Subject: Re: real random number generator idea -- any criticisms?
Date: Fri, 12 Nov 1999 07:00:22 -1000
[EMAIL PROTECTED] wrote:
>
> I have an idea for a random number generator on Windows NT/9x machines.
> The idea is an adaptation of a rng mentioned in Schneier's Applied
> Cryptography, Sec 17.14 in the subsection. "Using the Computer's Clock"
>
> Make an initial call to ::GetTickCount(). Keep calling the function
> repeatedly until the value changes, incrementing a counter each time.
> Take the LSB of the counter and use that as a bit of randomness. The
> resolution of the win32 function ::GetTickCount is about 10ms for NT,
> 55ms for 95.
This has been done before, Diehard was used to examine the bits.
The quality was not perfect, but the results were usually close
to the values that are desired from Diehard. But the results were
not distibuted evenly from 0 to 1, as a random input would produce.
The results clustered nearer to .9900 and 0.0100 for Diehard
than is desired.
------------------------------
Date: Fri, 12 Nov 1999 10:09:14 -0500
From: "Trevor Jackson, III" <[EMAIL PROTECTED]>
Crossposted-To: sci.math,sci.misc,sci.physics
Subject: Re: Proposal: Inexpensive Method of "True Random Data" Generation
Mike McCarty wrote:
> In article <[EMAIL PROTECTED]>, Coen Visser <[EMAIL PROTECTED]> wrote:
> )Mike McCarty wrote:
> )
> )> No individual string can be random. A string is or is not compressible,
> )
> )It is a definition: call a string random when it is incompressible.
>
> I was disputing your definition.
>
> [snip]
>
> )> You seem to be trying to decompose a single event, i.e. the generation
> )> of a string, into multiple events, i.e. the generation of each string
> )> element (or equivalently, generation of strings of length one element
> )> each), and then use the randomness or non-randomness of the latter
> )> events considered as a stochastic process as a means for determining
> )> the randomness of the single event of generation of the entire string.
> )
> )Ah, that was not what I meant. I was trying to make a point (badly)
> )about the inevitable occurence of regular patterns in random strings.
>
> If that's true, then we are talking about different subjects. I thought
> you were discussing randomness, and a putative definition in terms of
> compressibility.
>
> To reiterate: the compressibility or non-compressibility of any given
> string depends on the universe from which it is drawn. A given string
> has a "pattern" in it which leads it to be compressible (in the sense
> that the compressed string is actually shorter than the uncompressed
> version) only if one knows something about the universe from which it
> is drawn. It is not a property of an individual string.
>
> In order to further the exchange of information rather than talking at
> cross purposes, would you please supply putative definitions for:
>
> random variable
> random process
> stochastic process
> random number
> random string
Please don't. Overloading "random" with more definitions does _not_ lead to
insight. There are enough euphenisms available to address this issue using
precise terms without overlap or overloading.
------------------------------
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