Cryptography-Digest Digest #921, Volume #13 Fri, 16 Mar 01 20:13:00 EST
Contents:
Cesar principle (br)
Re: Factoring RSA (br)
Re: IP ("Fred")
Re: Factoring RSA ("Tom St Denis")
Re: Q: IP ("Fred")
Re: primes for Blum Blum Shub generator ("Joseph Ashwood")
Re: How to eliminate redondancy? ("Joseph Ashwood")
Re: Random and RSA ("Joseph Ashwood")
Re: What do we mean when we say a cipher is broken? (Was Art of Cryptography) (John
Savard)
Re: Cesar principle ("Joseph Ashwood")
Re: Cesar principle (br)
Re: Cesar principle (br)
Re: Cesar principle (br)
Shannon & Repeating Emanations (Frank Gerlach)
Re: ideas of D.Chaum about digital cash and whether tax offices are (John
Christensen)
Correct Posting: Shannon & Repeating Emanations (Frank Gerlach)
Re: Potential of machine translation techniques? (Joe H. Acker)
----------------------------------------------------------------------------
From: br <[EMAIL PROTECTED]>
Subject: Cesar principle
Date: Fri, 16 Mar 2001 18:28:30 -0400
what if I use "Cesar Principle" as a way of encryption using hudge
numbers?
Let Message M converted to hexadecimal number
Sample M= 15241a51423f16243121f12412d51245122 etc...
I encrypt using hudge number k=51241c1241536d etc... where the number of
digits is more than 500 (i.e).
So E=M+k
To decipher I have just to calculate D=E-k
It's very easy.
How the attacker could guess k?
If the length of M is < 500 digits I add end inside my plain text and
append remaining cells with "empty" text (any english text). Empty means
in this case to neglect in the message reading.
------------------------------
From: br <[EMAIL PROTECTED]>
Subject: Re: Factoring RSA
Date: Fri, 16 Mar 2001 18:37:46 -0400
My idea is very simple : if you multiply every prime number P by X, P*X
will be equal to 999999999999999999 ( (10^k) - 1) for k near the value
n. You can prouve that in the neighbour of (10^n) - 1 (just few values
of k), you will find P or Q.
------------------------------
From: "Fred" <[EMAIL PROTECTED]>
Subject: Re: IP
Date: Thu, 15 Mar 2001 18:39:46 -0500
=====BEGIN PGP SIGNED MESSAGE=====
Hash: SHA1
Hello,
It's simple, if you ahve a normal phone connection, you probably
have a dynamic IP adress ( becose every times you connect to your
provider, this provider assign you a modem ( aleatory ) ). But, you
can ask to your provider to have a Dedicated modem for a certain fee
per month. In this case, you have a static IP with your normal phone
connection.
After, if you use other technologie like cable os ADSL, etc, this
depand of your provider. They work by modem cluster ( all there
modems a divided in "cluster by district" in there distribution
central ). For exemple, I have a cable modem. 3 years ago I had a
static IP, becose I had a dedicated cable modem in the cluster of
district. But with the expension of the service, now, they change the
IP ( modem ) every month.
All other technology like fiber optical lines, backbones lines,
are static IPs.
Salutations,
Fred
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------------------------------
From: "Tom St Denis" <[EMAIL PROTECTED]>
Subject: Re: Factoring RSA
Date: Fri, 16 Mar 2001 23:46:03 GMT
"br" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED]...
> My idea is very simple : if you multiply every prime number P by X, P*X
> will be equal to 999999999999999999 ( (10^k) - 1) for k near the value
> n. You can prouve that in the neighbour of (10^n) - 1 (just few values
> of k), you will find P or Q.
That's such BS. If you multiply every prime upto SQRT(PQ) you will get a
gizillion (yes I made that up) bit number. Your method relies on randomly
hitting a multiple of P or Q. So does the method I posted.
Tom
------------------------------
From: "Fred" <[EMAIL PROTECTED]>
Subject: Re: Q: IP
Date: Thu, 15 Mar 2001 18:46:52 -0500
=====BEGIN PGP SIGNED MESSAGE=====
Hash: SHA1
Hello,
Yea sure, but personal firewall are cheap cost low protection.
They protect attacks from wanabie hackers with there Trojan software
or other time of attack. Personnal firewall are not a problem for
experimented crackers. But, 95% of the time, professional firewall
are not too.
If you are a normal home user, and dont have anything of
important to protect, and just need a protection about wannabe, why
dont use personnal firewall? They do the job! Nobody need a
professional firewall, and full security system to protect there
normal files ( letters, not so important text, etc ).
Salutations,
Fred
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------------------------------
From: "Joseph Ashwood" <[EMAIL PROTECTED]>
Subject: Re: primes for Blum Blum Shub generator
Date: Fri, 16 Mar 2001 13:44:57 -0800
Oops. My typo. That should have been:
while(NOT(isPrime(R))
My mistake. I apologize. That'll teach me to type faster than I can read.
The function to look for in openssl is BN_generate_prime. The documentation
on it is at http://www.openssl.org/docs/crypto/BN_generate_prime.html
Joe
"Dobs" <[EMAIL PROTECTED]> wrote in message news:98tn8e$aqv$[EMAIL PROTECTED]...
> Thanks for help :))))
> U mean that I have to choose randomly big number choose it if it is odd
and
> then choose if it is prime. If not add 2 to this number and choose it one
> more time if it is prime, right? I do not know what is function israndom,
I
> think that U meant isprime( that I have to choose if it is prime) I can
not
> see any point to check if it is random?
>
> U wrote that I can use to prime number generator from openssl, I download
> this openssl file, but there are so many directories, files , I can not
find
> it and I think if I found it it would be integrated with others libraries
> like *.h, and I could not use it because I am not so good at programing to
> make it work in my program.Perhaps U know any different source where I can
> find easier prime number generator or algorithm to it
------------------------------
From: "Joseph Ashwood" <[EMAIL PROTECTED]>
Subject: Re: How to eliminate redondancy?
Date: Fri, 16 Mar 2001 15:08:40 -0800
No I prefer compression that meets the transform requirements to be called a
1-1 onto transform. This has a very well defined meaning in computer
science, it means simply that every item in the input set maps to one and
only one member of the output set, and every member of the output set maps
to one and only one member of the input set. Cryptographically I prefer all
transforms to be 1-1 onto. What you call "1-1" is neither a sub nor superset
of the set of 1-1 onto transforms, it is a seperate set.
Joe
"SCOTT19U.ZIP_GUY" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]...
> [EMAIL PROTECTED] (Joseph Ashwood) wrote in <#bd5eebrAHA.296@cpmsnbbsa09>:
>
> >There are 3 possibilities.
> >1 to many (expansion)
> >many to 1 (lossy compression)
> >and 1-1 (convolution, may be compression, expansion, or unchanged)
> >All of these are possible for removing redundancy, although 1-1 is the
> >most reasonable to use, with 1-1 onto being most preferable.
> > Joe
> >
>
> Interesting comment Joe. So you prefer compression that is 1-1.
> Let's be a little more specific. If you have to compression methods
> that compress a given file type to a the same size range.
> Which would you rather use.
> 1) that when a false key is used you usually get a file that could
> not have been compresses with the compressor you used.
> 2) One that no matter what key an attacker tries it leads to a file
> that could have been compresses. Thud forcing the attacker to use
> other information if any about the possible file he thinks may have
> been encrypted.
>
> Assuming maybe falsely that you would prefer number 2.
> which method do you actually use. I think most people rather
> foolishly think that if they remove the so called headers from
> the front of the file that they are using something close to
> number 2. While they most likely are not.
>
>
>
>
> David A. Scott
> --
> SCOTT19U.ZIP NOW AVAILABLE WORLD WIDE
> http://www.jim.com/jamesd/Kong/scott19u.zip
> Scott famous encryption website **now all allowed**
> http://members.xoom.com/ecil/index.htm
> Scott LATEST UPDATED source for scott*u.zip
> http://radiusnet.net/crypto/ then look for
> sub directory scott after pressing CRYPTO
> Scott famous Compression Page
> http://members.xoom.com/ecil/compress.htm
> **NOTE EMAIL address is for SPAMERS***
> I leave you with this final thought from President Bill Clinton:
------------------------------
From: "Joseph Ashwood" <[EMAIL PROTECTED]>
Subject: Re: Random and RSA
Date: Fri, 16 Mar 2001 15:49:20 -0800
> Factoring N is it so hard?
I'll let you answer that question yourself. Go to the page
http://www.rsasecurity.com/rsalabs/challenges/factoring/lists.html
and get the lists. If you can factor any of them, I will be suitably
impressed.
> If the use of pseudorandomness function is not secure,
Correction the use of a pseudorandomness function is not _provably_ secure.
> why RSA is seen
> as secure.
Try factoring the numbers on the challenge list and find out, you'll find
that it takes more memory or more compute power than can be afforded, and
none of those are even the size I use for crypto.
> When you multiply two prime big numbers, the operation is not
> random? P has a sequence of digits that is non ramdom, Q too.
> So I don't understand?
The important matter is not random/non-random, but difficulty in reversing
the process. Currently factoring takes a massive amount of effort so it
qualifies.
> If someone can break a pseudo-random function, why can't he break a
> deterministic function?
But the factors of the RSA modulus are at least pseudo-random, this makes it
very difficult to factor.
Joe
------------------------------
From: [EMAIL PROTECTED] (John Savard)
Subject: Re: What do we mean when we say a cipher is broken? (Was Art of Cryptography)
Date: Sat, 17 Mar 2001 00:03:53 GMT
On Fri, 16 Mar 2001 13:42:32 -0600, [EMAIL PROTECTED] (wtshaw) wrote,
in part:
>A more important question to me is what ciphers
>have a useful unicity distance, and how large are they.
Unicity distance is an information-theoretic quantity, and depends
solely on the size of the key.
John Savard
http://home.ecn.ab.ca/~jsavard/crypto.htm
------------------------------
From: "Joseph Ashwood" <[EMAIL PROTECTED]>
Subject: Re: Cesar principle
Date: Fri, 16 Mar 2001 16:12:44 -0800
It's actually very simple. Known-plaintext attack
Grab a known block, subtract your known plaintext, it spits out the key, use
it
Known text-type (e.g. English)
Grab 2 blocks A, B
C = A-B
C is not Decrypted(A)-Decrypted(B)
use the general lack of entropy to solve for A
A is now a Known-plaintext, use the first method.
Joe
"br" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED]...
> what if I use "Cesar Principle" as a way of encryption using hudge
> numbers?
> Let Message M converted to hexadecimal number
> Sample M= 15241a51423f16243121f12412d51245122 etc...
> I encrypt using hudge number k=51241c1241536d etc... where the number of
> digits is more than 500 (i.e).
> So E=M+k
> To decipher I have just to calculate D=E-k
>
> It's very easy.
>
> How the attacker could guess k?
>
> If the length of M is < 500 digits I add end inside my plain text and
> append remaining cells with "empty" text (any english text). Empty means
> in this case to neglect in the message reading.
------------------------------
From: br <[EMAIL PROTECTED]>
Subject: Re: Cesar principle
Date: Fri, 16 Mar 2001 19:29:31 -0400
You have to know the length of the block, it could be variable.
the key length could be variable etc...
Suppose that the text is crypted before applying cesar principle.
I may use Cesar principle to any message I want to transmit.
Joseph Ashwood wrote:
>
> It's actually very simple. Known-plaintext attack
> Grab a known block, subtract your known plaintext, it spits out the key, use
> it
>
> Known text-type (e.g. English)
> Grab 2 blocks A, B
> C = A-B
> C is not Decrypted(A)-Decrypted(B)
> use the general lack of entropy to solve for A
> A is now a Known-plaintext, use the first method.
>
> Joe
>
> "br" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED]...
> > what if I use "Cesar Principle" as a way of encryption using hudge
> > numbers?
> > Let Message M converted to hexadecimal number
> > Sample M= 15241a51423f16243121f12412d51245122 etc...
> > I encrypt using hudge number k=51241c1241536d etc... where the number of
> > digits is more than 500 (i.e).
> > So E=M+k
> > To decipher I have just to calculate D=E-k
> >
> > It's very easy.
> >
> > How the attacker could guess k?
> >
> > If the length of M is < 500 digits I add end inside my plain text and
> > append remaining cells with "empty" text (any english text). Empty means
> > in this case to neglect in the message reading.
------------------------------
From: br <[EMAIL PROTECTED]>
Subject: Re: Cesar principle
Date: Fri, 16 Mar 2001 19:33:12 -0400
Substracting 15342-14253 is not the same as substracting 153 - 142
Joseph Ashwood wrote:
>
> It's actually very simple. Known-plaintext attack
> Grab a known block, subtract your known plaintext, it spits out the key, use
> it
>
> Known text-type (e.g. English)
> Grab 2 blocks A, B
> C = A-B
> C is not Decrypted(A)-Decrypted(B)
> use the general lack of entropy to solve for A
> A is now a Known-plaintext, use the first method.
>
> Joe
>
> "br" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED]...
> > what if I use "Cesar Principle" as a way of encryption using hudge
> > numbers?
> > Let Message M converted to hexadecimal number
> > Sample M= 15241a51423f16243121f12412d51245122 etc...
> > I encrypt using hudge number k=51241c1241536d etc... where the number of
> > digits is more than 500 (i.e).
> > So E=M+k
> > To decipher I have just to calculate D=E-k
> >
> > It's very easy.
> >
> > How the attacker could guess k?
> >
> > If the length of M is < 500 digits I add end inside my plain text and
> > append remaining cells with "empty" text (any english text). Empty means
> > in this case to neglect in the message reading.
------------------------------
From: br <[EMAIL PROTECTED]>
Subject: Re: Cesar principle
Date: Fri, 16 Mar 2001 19:52:49 -0400
Now you are talking about using known-plain text attack.
Why in your previous contribution about two properties, you rejected the
use of dictionnaries by cryptanalists?
I'm working on sample using the two properties to show how difficult is
to decrypt cipher using this technic. I'm writing it.
And all AI algo are helpless toward this technic.
Cryptanalist have no way build a program. He has to read every ouptput
for every key. Without reading he can't attack it.
I recognize that I'm just an amateur cryptograph. But, I am confident on
my power to propose new ideas.
Thank you for your useful comments.
Joseph Ashwood wrote:
>
> It's actually very simple. Known-plaintext attack
> Grab a known block, subtract your known plaintext, it spits out the key, use
> it
>
> Known text-type (e.g. English)
> Grab 2 blocks A, B
> C = A-B
> C is not Decrypted(A)-Decrypted(B)
> use the general lack of entropy to solve for A
> A is now a Known-plaintext, use the first method.
>
> Joe
>
> "br" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED]...
> > what if I use "Cesar Principle" as a way of encryption using hudge
> > numbers?
> > Let Message M converted to hexadecimal number
> > Sample M= 15241a51423f16243121f12412d51245122 etc...
> > I encrypt using hudge number k=51241c1241536d etc... where the number of
> > digits is more than 500 (i.e).
> > So E=M+k
> > To decipher I have just to calculate D=E-k
> >
> > It's very easy.
> >
> > How the attacker could guess k?
> >
> > If the length of M is < 500 digits I add end inside my plain text and
> > append remaining cells with "empty" text (any english text). Empty means
> > in this case to neglect in the message reading.
------------------------------
From: Frank Gerlach <[EMAIL PROTECTED]>
Subject: Shannon & Repeating Emanations
Date: Sat, 17 Mar 2001 02:55:23 +0100
>
Maybe a quick-and-dirty information-theoretic calculation can give a clue
on the relationship of SNR and signal repetitions.
In the following, these Variables are used:
DS digital signal containing target signal
TS target signal
C Transmission rate in bit/s
B Bandwith in Hz
SNR Signal to Noise Ratio in 1/1
fc Clock Frequency of the signal in Hz
R repetitions of signal
fr target signal repetition rate in 1/s
l length of the target signal in bits
t recording time
Shannon:
C=B*log2(1+SNR)
Assuming the targeted signal TS is part of of a simple digital (binary)
signal DS, a rough estimation of the DS' bandwith is
Maybe a quick-and-dirty information-theoretic calculation can give a clue
on the relationship of SNR and signal repetitions.
In the following, these Variables are used:
DS digital signal containing target signal
TS target signal
C Transmission rate in bit/s
B Bandwith in Hz
SNR Signal to Noise Ratio in 1/1
fc Clock Frequency of the signal in Hz
R repetitions of signal
fr target signal repetition rate in 1/s
l length of the target signal in bits
t recording time
Shannon:
C=B*log2(1+SNR)
Assuming the targeted signal TS is part of of a simple digital (binary)
signal DS, a rough estimation of the DS' bandwith is
B=fc.
For an exact calculation,an integral of the fourier transformation of the
signal DS would have to be used. Still, B=fc appears to be a good
approximation.
The maximum transmission rate of DS is
C=fc*log2(1+SNR)
The percentage of TS data transmitted is
p=(fr*l)/fc
This means that the maximum TS transmission rate Cts is
Cts=C*p
B=fc.
For an exact calculation,an integral of the fourier transformation of the
signal DS would have to be used. Still, B=fc appears to be a good
approximation.
The maximum transmission rate of DS is
C=fc*log2(1+SNR)
The percentage of TS data transmitted is
p=(fr*l)/fc
This means that the maximum TS transmission rate Cts is
Cts=C*pCts=C*fr*l/fc
To successfully intercept the target signal, the minimum recording time is
t=l/Cts
t=l/(fc*log2(1+SNR)*fr*l/fc)
t=1/(fr*log2(1+SNR))
Two interesting points:
-the minimum monitoring time is directly related to the frequency of the
repetition of the target signal
-neither length of target signal nor the base frequency of the signal is
relevant !!
Some sample calculations:
Repetition rate 100/s
SNR(dB)=-10 ->.00002020150249261588 (h)
SNR(dB)=-40 ->.01925505103726054377 (h)
SNR(dB)=-70 ->19.25408931159198693411 (h)
SNR(dB)=-100 ->19254.08835140925966709589 (h)
SNR(dB)=-130 ->19254091.56377203118620638112 (h)
This means that cryptographic devices should be designed for -100dB SNR,
whilst -70 dB should be enough for displays. This assumes that no critical
data
is displayed for more than 8 hours at a time.
------------------------------
From: John Christensen <[EMAIL PROTECTED]>
Reply-To: [EMAIL PROTECTED]
Crossposted-To: talk.politics.crypto,alt.cypherpunks
Subject: Re: ideas of D.Chaum about digital cash and whether tax offices are
Date: Fri, 16 Mar 2001 21:06:24 -0500
George Weinberg wrote:
> On Thu, 15 Mar 2001 19:43:16 -0500, John Christensen
> <[EMAIL PROTECTED]> wrote:
>
> >Thanks for the info, but it's not really exactly what I'm looking for.
> >You see, I would like to have something similar to Deja, which
> >is now defunct. It allowed me, with an account, to sit down at a
> >terminal anywhere and post. So I could post from the library if
> >I wanted.
> >
> >Remailers, as I understand, would require that I download a
> >client program, and I of course can't do that at a remote location.
> >
>
> Technically you don't NEED the client program, it just makes
> using the remailers a lot easier. You could, for example,
> generate properly formatted messages at home and
> store them on a floppy. All you need at the library
> is a regular mail client (which you may or may not have).
>
> George
I have no access to the floppy drives there.
B'sides, sounds like a big pain in the neck to
write stuff at home then go to the library just to
post it.
I tried mailandnews, but they post
my real name on everything I write.
I didn't have a problem with deja knowing my real
name, but I didn't want it plastered all
around the Internet, either, so that anybody
who didn't like my opinion could come after me.
------------------------------
From: Frank Gerlach <[EMAIL PROTECTED]>
Subject: Correct Posting: Shannon & Repeating Emanations
Date: Sat, 17 Mar 2001 03:04:02 +0100
(linux and netscape... :-( )
Maybe a quick-and-dirty information-theoretic calculation can give a clue
on the relationship of SNR and signal repetitions.
In the following, these Variables are used:
DS digital signal containing target signal
TS target signal
C Transmission rate in bit/s
B Bandwith in Hz
SNR Signal to Noise Ratio in 1/1
fc Clock Frequency of the signal in Hz
R repetitions of signal
fr target signal repetition rate in 1/s
l length of the target signal in bits
t recording time
Shannon:
C=B*log2(1+SNR)
Assuming the targeted signal TS is part of of a simple digital (binary)
signal DS, a rough estimation of DS' bandwith is
B=fc.
For an exact calculation,an integral of the fourier transformation of the
signal DS would have to be used. Still, B=fc appears to be a good
approximation.
The maximum transmission rate of DS is
C=fc*log2(1+SNR)
The percentage of TS data transmitted is
p=(fr*l)/fc
This means that the maximum TS transmission rate Cts is
Cts=C*p
Cts=C*fr*l/fc
To successfully intercept the target signal, the minimum recording time is
t=l/Cts
t=l/(fc*log2(1+SNR)*fr*l/fc)
t=1/(fr*log2(1+SNR))
Two interesting points:
-the minimum monitoring time is directly related to the frequency of the
repetition of the target signal
-neither length of target signal nor the base frequency of the signal is
relevant !!
Some sample calculations:
Repetition rate 100/s
SNR(dB)=-10 ->.00002020150249261588 (h)
SNR(dB)=-40 ->.01925505103726054377 (h)
SNR(dB)=-70 ->19.25408931159198693411 (h)
SNR(dB)=-100 ->19254.08835140925966709589 (h)
SNR(dB)=-130 ->19254091.56377203118620638112 (h)
This means that cryptographic devices should be designed for -100dB SNR,
whilst -70 dB should be enough for displays. This assumes that no critical
data
is displayed for more than 8 hours at a time.
------------------------------
From: [EMAIL PROTECTED] (Joe H. Acker)
Subject: Re: Potential of machine translation techniques?
Date: Sat, 17 Mar 2001 02:03:12 +0100
Mok-Kong Shen <[EMAIL PROTECTED]> wrote:
> Mike Rosing wrote:
> >
> > Mok-Kong Shen wrote:
> > >
> > > I heard on the other hand that there are successful
> > > translation software between Japanese and English.
> >
> > Yeah, but it's not all that successful! I spent a week with a
> > guest from Japan who had a hand held translator and a Mac with
> > a translator. It took us 5 minutes per concept on a good day,
> > and trying whole sentences was very funny. Without the translator,
> > it would have been much, much more difficult so they are definitly
> > useful. But a long ways from being "successful".
>
> I have no experience but I have the conjecture that what
> you met with probably doesn't correspond to the (forefront
> of) state of the art. There is one software system,
> Verbomil, that claims to provide mobile phone users with
> simultaneous dialog interpretation services for restricted
> topics in three languages, German, English and Japanese.
> (Of course, the cost etc. of the system could under
> circumstances be an issue.) Note that this is speech
> translation which is much more involved than mere text
> translation. A pointer is:
It's actually called VERBMOBIL, a project by several German universities
and companies like IBM. It was intended to do automated
speaker-independent translation of German, English and Japanese in
realtime. Early demonstrations failed miserably, but of course, there
were many results as well. Most problems probably weren't due to
translation components but rather to understanding and disambiguation of
*speaker-independant* fluent speech. Some of the scientists involved in
the project were aware that the ambitious goals of the project wouldn't
be reached. As I've lost it somewhat out of sight, I can't tell how well
VERBMOBIL actually worked. A quick search on google should give you more
information.
Regards,
Erich
------------------------------
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