Cryptography-Digest Digest #252, Volume #9 Fri, 19 Mar 99 08:13:04 EST
Contents:
SCOTT ADAPTIVE COMPRESSION SUITABLE FOR ENCRYPTION (karl malbrain)
Re: ATM project ("hapticz")
Re: pRNG that is "predictable to the left"? ("Steve Myers")
Re: Site Change (John Savard)
Re: To break 40-bit DES ("Keith Brodie")
free CryptoGraphy library Sites ([EMAIL PROTECTED])
Re: ATM project (David A Molnar)
Tuxedo and Bowtie (wtshaw)
Re: ? Random et BigInteger (Gallicus)
? String ---> short[] ---->bit[] in Java ? (Gallicus)
Pb of cryptanalyse (Zorl is Back)
Re: To break 40-bit DES (Cedomir Igaly)
Re: To break 40-bit DES ([EMAIL PROTECTED])
----------------------------------------------------------------------------
From: karl malbrain <[EMAIL PROTECTED]>
Subject: SCOTT ADAPTIVE COMPRESSION SUITABLE FOR ENCRYPTION
Date: Fri, 19 Mar 1999 02:39:10 GMT
In article <7cnnk7$sro$[EMAIL PROTECTED]>,
[EMAIL PROTECTED] wrote:
> I made some random test cases and added a new case to remove
> a bug on the old version. My main criteria is that any file
> can be uncompressed by my code and then when recompressed
> you get same file (...) the all Zero token has always 8 or
> more zeros.
In the CONTINUING effort to teach GRAMMAR, under ENGLISH rules, the <<re>>
prefix is used to indicate REVERSE/ITERATION. The idea behind compression is
that REDUNDANCY -- read VULGARITY -- is removed under a <<repeat-count>>
argument to the EXPANDER.
BTW, <<token>> is used to indicate a NOMINATIVE value by replacement. Karl M
============= Posted via Deja News, The Discussion Network ============
http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own
------------------------------
From: "hapticz" <[EMAIL PROTECTED]>
Subject: Re: ATM project
Date: Thu, 18 Mar 1999 22:55:16 -0500
ZG8geW91IGtub3cgd2hhdCBhICJvbmUgd2F5IiBoYXNoIGlzPw0KDQotLSANCmJlc3QgcmVnYXJk
cw0KaGFwdGljekBlbWFpbC5tc24uY29tDQoNCg0K
------------------------------
From: [EMAIL PROTECTED] ("Steve Myers")
Subject: Re: pRNG that is "predictable to the left"?
Date: 19 Mar 99 04:42:13 GMT
Christoph Haenle wrote in message <7cir3f$[EMAIL PROTECTED]>...
>Hi,
>
>I'm looking for a pseudorandom number generator that _is_ predictable
>to the left, but unpredictable to the right. Intuitively, if the
>random number generator produces values x_1, x_2, etc. I want someone
>who knows x_n to be able to recover all previous values, but not the
>next ones. Also, given x_n, any x_i, i<n should be _easily_ computable
>(that is, no backwards-iteration through x_{n-1}, x{n-2}, should be
>needed).
It is an easy theorem to prove that a generator is unpredictable to the left
iff the generator is unpredictable to the right iff the generator is
pseudo-random. Therefore, you have a generator which is predictable in both
directions, you're just no aware of the predictibility in one direction. As
a direct corollary your construction must fail, and so must all further
attempts.
Steve
------------------------------
From: [EMAIL PROTECTED] (John Savard)
Subject: Re: Site Change
Date: Wed, 17 Mar 1999 23:03:30 GMT
[EMAIL PROTECTED] (Paul Rubin) wrote, in part:
>Btw, you can see your page without the Xoom frame by hitting:
Yes, I know that, but encouraging that sort of thing would be considered a
violation of the TOS...
John Savard (teneerf is spelled backwards)
http://members.xoom.com/quadibloc/index.html
------------------------------
From: "Keith Brodie" <[EMAIL PROTECTED]>
Subject: Re: To break 40-bit DES
Date: Fri, 19 Mar 1999 03:41:53 GMT
There is no 40 bit DES - It is defined to have a 56 bit key.
--
Keith Brodie KF6QEK
[EMAIL PROTECTED]
Gustavo wrote in message <7criij$79j$[EMAIL PROTECTED]>...
>Hi all,
>It is well known that any algorithm with
>key's variability of 40 bits can be easily
>broken.
>Does anyone know how long
>does the fastest software attack to
>40-bit DES take to find the correct key
>(for instance on a Pentium 300)?
>Thank you.
>Gustavo
>
>
------------------------------
From: [EMAIL PROTECTED]
Subject: free CryptoGraphy library Sites
Date: Fri, 19 Mar 1999 05:52:20 GMT
hi
I'm looking for free but a reliable cryptography library with DES/RC4 and
MD5/SHA1 implementations( that's all I require ) for commercial purposes
outside USA.I've seen CryptLib , Crypto++ and RSA-Euro already. CAn Anyone
suggest me others
Thanx in advance !!
Manish Mahajan
============= Posted via Deja News, The Discussion Network ============
http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own
------------------------------
From: David A Molnar <[EMAIL PROTECTED]>
Subject: Re: ATM project
Date: 19 Mar 1999 05:32:37 GMT
hapticz <[EMAIL PROTECTED]> wrote:
> do you know what a "one way" hash is?
>
You might try http://theory.lcs.mit.edu/~miccianc/papers/pow.ps
"Perfectly One Way Probabilistic Hash Functions"
for a discussion of what one way hashes are, and what "one way"
means -- it means that given the output of the hash function,
it's hard to find something which produced that output...but
it gets more complicated than that.
-David Molnar
------------------------------
From: [EMAIL PROTECTED] (wtshaw)
Subject: Tuxedo and Bowtie
Date: Thu, 18 Mar 1999 23:41:35 -0600
Yep...two more ciphers in a series, both taking base 100 to base 33. In
reviewing the detailed maps of Texas, I find that Tuxedo is located near
100W and 33N. Actually, it is little more than a mere junction, sorry
about that. For some, they are batting 100 if they mix a tux with the
33rd degree.
Considering the numbers, Tuxedo fits a bit of the large size, but is still
within the 10% parameter for 10^3=1000 and 33^2=1089. In Tuxedo
6/12/18/24, those quantitites of digits are rearranged according a
variable length key. Each three digits are converted to two ciphertext
characters from a set of 33.
Bowtie 20 converts each three digits from base 100 plaintext input to 10
bits, 20 bits for 3 plaintext characters, which can be shuffled according
to a key. As above, the result is converted to ciphertext characters from
a set of 33.
To make things a little more interesting for both algorithms, a ciphertext
set of 36 characters is used, allowing three characters to be inserted as
optional nulls, the last three in the substitution key. Output would then
look like it was base 36.
Default keys for these ciphers are as follows:
Subs(Tux): abcdefghi jklmnopqr stuvwxyz0 123456789
Trans(Tux): abcdef ghijkl mnopqr stuvwx
Subs(BT): abcdefghijklmnopqrstuvwxyz0123456789
Trans(BT): abcdefghijklmnopqrst
I suppose that 17 of these ciphers starting with base 100 demonstrate the
tremendous variety of what can be done. There are more that could be
done, but the idea was to do the simplest.
As a result of dealing with many of these ciphers, I have begun to
organize them according to general structure, not dependent on the actual
bases. As I encounter different ones, I simply add another numbered
type. Several ciphers may have the same outline. This is all not just an
idle effort, as subtile ideas are starting to gel.
Where to go from here? One frequent poster has suggested that it would be
interesting to see what bases could be easily translated to base 64, for
ciphertext in one of the common sets. I see no reason not to do a few of
them. Of course, the mathematics for figuring them is available to
everyone.
Actually, we have one already, Granville 14/28/42/64, with plaintext in
100, and ciphertext in 64. One quick listing would be 100-10-64, where
the 10 shows the size information units, digits in this case, that are
transposed.
For different sized plaintexts, new input interfacing is required, several
of which I have already done for various ciphers. The next cipher up, if
everything goes as planned, is going to use base 27 for input and base 100
for output. The listing of 27-12-64 should hint as its nature. (Some of
the conversions appear useful, but not for small sized transposition
keys. I'll mention them in the future.)
In fact, base 12 information units are useful for several conversions to
base 64. I have not previous thought what I might call such base 12
creatures, perhaps doits?
This allows noits for those in base 11. So, the list is bits, trits,
penits, hexits, hepits, digits, noits, and doits for base 2, 3, 5, 6, 7,
10, 11, and 12 information units.
One dodit would equal (log 12/log 2) bits. Notice that each has a distinct
value, which can be roughly converted to the others, but none is a simple
fraction or multiple of another in size.
--
It's a game within a game within a game.--Gen. Odom
------------------------------
From: [EMAIL PROTECTED] (Gallicus)
Crossposted-To: fr.comp.lang.java
Subject: Re: ? Random et BigInteger
Date: Thu, 18 Mar 1999 00:01:05 GMT
Je suis arriv� ici :
private BigInteger aleatoire(BigInteger a, int numBits) {
/* a re�oit la limite inf�rieure, et numBits la limite sup�rieure -1 sous
la forme de 2 ^ numBits, puis j'installe une instance de BigInteger(int
numBits, Random rnd) */
Random rnd;
BigInteger alea;
rnd = new Random();
do {
alea = new BigInteger(numBits,rnd);
}
while (a == a.max(alea));
return alea;
}
Cela ressemble vaguement � une solution mais tr�s imparfaite. O� sont les
erreurs ?
Merci d'avance.
Gallicus.
------------------------------
From: [EMAIL PROTECTED] (Gallicus)
Subject: ? String ---> short[] ---->bit[] in Java ?
Date: Fri, 19 Mar 1999 09:04:40 GMT
in Java 1.2
I have a String = "BONJOUR"...
I take the first character's ascii value...
"B" val = 66...
then I do : val - 32 = 34...
34 in base 2 = 100010...
I put each of these six bits in bit[].
I take the next character, "O" val = 79.....
val - 32 = 47 ... etc....
What is the best way to obtain bit[] for all the string's characters ?
TIA.
Gallicus.
------------------------------
From: Zorl is Back <[EMAIL PROTECTED]>
Subject: Pb of cryptanalyse
Date: Fri, 19 Mar 1999 11:16:29 +0100
I want to break a code but i'm not capable. Anybody can help me and
explain to me how the crypt is made.
I know that :
The crypt is symetric
for a word, you obtain always the same result
The crypt works on the only 31 first characters
examples:
coucou zHkBQMJrF3itaGw0Gadmu9v28iyJkp5NC9FwHVuh
bonjour qX6zvKp64f#qBF69XGB6SalXrDZBEswX4RH0DoKM
toto12 HJ1AUD2rLxfKsvp2IP8s99#0L#s0Q8tgtYOQZiim
abcdefghij goMPLKoTY2bSRsQLwSQdnA54ll19bI#d0iUkEJVY
12reponse OMPbY4WsHFZMIKDTolj5q$bQ5qO3ts6B$ggHzsQ$
1234567890 W095N4wPo2EIaZs$glFNWIWWjXbGDJjpPyY3jkyM
COUCOU OOYSAG14XtNNiAugWJLkkNjPaUHghMNxP3od1Igz
BONJOUR Sj0ge28Mm02s98nbUfIwCC5gHSZ8u4r0NHQT15dj
I would like to know the method
Please help me
Tks
------------------------------
From: Cedomir Igaly <[EMAIL PROTECTED]>
Subject: Re: To break 40-bit DES
Date: Fri, 19 Mar 1999 12:29:17 +0000
[EMAIL PROTECTED] wrote:
> They may be thinking of RC5-w/r/5 or RC6-w/r/5. BTW, you can use DES with a
> 40-bit key, if you expand it with zeros. (but why?)
One reason for that might be if you want to export it from USA :-)) Like, for
example, exported versions of SSL.
Regards,
C.I.
------------------------------
From: [EMAIL PROTECTED]
Subject: Re: To break 40-bit DES
Date: Fri, 19 Mar 1999 11:56:16 GMT
> There is no 40 bit DES - It is defined to have a 56 bit key.
>
> --
> Keith Brodie KF6QEK
> [EMAIL PROTECTED]
> Gustavo wrote in message <7criij$79j$[EMAIL PROTECTED]>...
> >Hi all,
> >It is well known that any algorithm with
> >key's variability of 40 bits can be easily
> >broken.
> >Does anyone know how long
> >does the fastest software attack to
> >40-bit DES take to find the correct key
> >(for instance on a Pentium 300)?
> >Thank you.
> >Gustavo
They may be thinking of RC5-w/r/5 or RC6-w/r/5. BTW, you can use DES with a
40-bit key, if you expand it with zeros. (but why?)
Tom
============= Posted via Deja News, The Discussion Network ============
http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own
------------------------------
** FOR YOUR REFERENCE **
The service address, to which questions about the list itself and requests
to be added to or deleted from it should be directed, is:
Internet: [EMAIL PROTECTED]
You can send mail to the entire list (and sci.crypt) via:
Internet: [EMAIL PROTECTED]
End of Cryptography-Digest Digest
******************************
