Cryptography-Digest Digest #987, Volume #12 Mon, 23 Oct 00 14:13:01 EDT
Contents:
Re: Help ,Does anybody know ??? (Mok-Kong Shen)
Re: Rijndael implementations (Richard Heathfield)
Re: How to post absolutely anything on the Internet anonymously (zapzing)
Re: Looking for C Source Code to stream compression algo (Cronos)
Re: Steganography books (zapzing)
Re: Huffman stream cipher. (Richard Heathfield)
SDMI announcement (Scott Craver)
Re: ---- As I study Rinjdael... ("Falissard")
Re: On block encryption processing with intermediate permutations (James Felling)
Re: How about the ERIKO-CHAN cipher? (James Felling)
Re: My comments on AES (James Felling)
Re: Hypercube/FFT encryption (Mok-Kong Shen)
Re: What is meant by non-Linear... (Mok-Kong Shen)
Finding Sample implementation for DES and IDEA (Steven Wu)
Re: SDMI announcement (jungle)
Re: On block encryption processing with intermediate permutations (Bryan Olson)
Re: How to post absolutely anything on the Internet anonymously (jungle)
Re: On block encryption processing with intermediate permutations (Mok-Kong Shen)
Re: Finding Sample implementation for DES and IDEA (Mok-Kong Shen)
----------------------------------------------------------------------------
From: Mok-Kong Shen <[EMAIL PROTECTED]>
Subject: Re: Help ,Does anybody know ???
Date: Mon, 23 Oct 2000 18:29:10 +0200
"SCOTT19U.ZIP_GUY" wrote:
>
> [EMAIL PROTECTED] wrote in <8t14p9$mj4$[EMAIL PROTECTED]>:
>
> >In article <[EMAIL PROTECTED]>,
> > [EMAIL PROTECTED] (SCOTT19U.ZIP_GUY) wrote:
> >> It is not that hard to code your self. But it
> >> is not considered a strong method of encryption. It
> >> has lots of weaknesses.
> >
> >RSA is not considered strong encryption? That's news to me. RSA is as
> >far as anyone knows a strong encryption method because of the difficulty
> >of factoring large numbers. If you chose large enough primes to generate
> >your private key, it is comparable in strength to many good block
> >ciphers (if not even better). The reason it is not often used for file
> >encryption is that it is slow when working with large amounts of data.
> >Hence, it's a great method for exchanging keys (which are small compared
> >to most files).
> >
>
> Even the FAQ shows RSA is weak compared to most other encryption
> methods. It is used for secrect key exchange since they are not many
> other ways to do public key. But even you have the ability to read
> the FAQ which shows that you need far longer keys then normal
> encryption to get what the current open literature grus consider
> safe.
> It is weak since it is a zero information type of encryption where
> one kows for sure that if a test key works then you have exactly the
> file that was encrypted even if is random. There have been articles
> saying how one could use choosen plaintext attacks agains pure RSA
> encryption. Even MR BS or Wagner both of whom hate my guts would tell
> you that it is a bad idea. Since you don't trust my word and you
> seem to lazy to look into it. Why don't you ask THEM!
I have not asked 'THEM' but I don't understand what you
wrote. (1) Different encryption algorithms may need by nature
different amounts of secret material and have different
processing efficiency (speed). So difference in key length
says yet nothing. It is the economy of achieving the
same security that matters. From this it comes that
different algorithms are suitable for different purposes.
(2) What is the significance of 'if a test key works'?
Do you mean that by 'chance' one picks the right key?
If yes, then that chance is smaller when the key is longer,
isn't it?
> >The most obvious way to encrypt a file using RSA (and the way PGPDisk
> >does it), is to encrypt the symmetric key used for a block cipher such
> >as CAST with RSA, and then encrypt the file using the (faster) block
> >cipher.
>
> Obviously you were to lazy to check thread the original poster wanted
> to use pure RSA for the whole thing.
This is a point between you and [EMAIL PROTECTED] and
hence I have no comment.
M. K. Shen
------------------------------
Date: Mon, 23 Oct 2000 17:15:48 +0100
From: Richard Heathfield <[EMAIL PROTECTED]>
Subject: Re: Rijndael implementations
Tim Tyler wrote:
>
> Daniel James <[EMAIL PROTECTED]> wrote:
> : In article <[EMAIL PROTECTED]>, Tim Tyler wrote:
>
> :> I do think a fixed size 32-bit unit is a desirable thing to have a
> :> term for. Perhaps there's an existing technical term for 32-bit units.
>
> : "int" would be a poor choice [...] I quite like "mouthful" for 4 bytes []
>
> Wonderful. You could even spell it "moythful" to get more into the spirit
> of deriving information units from natural words ;-)
I think you'll find that for a 32-bit quantity, 'dynner' is already in
the literature. ;-)
[Ref: Jargon File]
<snip>
--
Richard Heathfield
"Usenet is a strange place." - Dennis M Ritchie, 29 July 1999.
C FAQ: http://www.eskimo.com/~scs/C-faq/top.html
66 K&R Answers: http://users.powernet.co.uk/eton/kandr2/index.html (31
to go)
------------------------------
From: zapzing <[EMAIL PROTECTED]>
Crossposted-To: talk.politics.crypto,alt.freespeech
Subject: Re: How to post absolutely anything on the Internet anonymously
Date: Mon, 23 Oct 2000 16:11:28 GMT
In article <[EMAIL PROTECTED]>,
Anthony Stephen Szopa <[EMAIL PROTECTED]> wrote:
> > Anonymity and privacy seem destined to go the way of the Dodo. When
the
> > government's nano-scale spy robots are everywhere, escaping from
their
> > view long enough to do anything in private will be very, very
difficult.
> > --
> > __________ Lotus Artificial Life http://alife.co.uk/
[EMAIL PROTECTED]
> > |im |yler The Mandala Centre http://mandala.co.uk/ Surf against
sewage.
>
> Then you accept the total destruction of the US Constitution and our
> way of life?
>
> I just don't think you can have unbridled use of nano technology and
> seriously harbor any hopes of preserving our political system.
>
I do not seriously harbor any hopes of preserving
"our" political constitution. What is it about
the present political system that you like, BTW?
--
Void where prohibited by law.
Sent via Deja.com http://www.deja.com/
Before you buy.
------------------------------
From: Cronos <[EMAIL PROTECTED]>
Subject: Re: Looking for C Source Code to stream compression algo
Date: Mon, 23 Oct 2000 17:27:08 +0100
Thanks, I was in a rush and mistakenly posted to wrong group
<whoops,sorry>.
On Mon, 23 Oct 2000 02:10:36 GMT, Benjamin Goldberg
<[EMAIL PROTECTED]> wrote:
>Cronos wrote to sci.crypt:
>>
>> Hi,
>>
>> I am looking for the source code to a public domain stream compression
>> algorithm, better than RLE. I've had a look around at some
>> implementations of LZ algorithms, but they mostly seem to work on
>> blocks and I havent found any really clean source code. I just
>> basically want two functions for a win32 program:
>> BOOL ReadFileCompressed(HANDLE sfile,byte Rbyte)
>> BOOL WriteFileCompressed(HANDLE sfile,byte *Wbyte)
>> and maybe a Flush function to clear any buffer.
>> or some source code which could be converted to this kind of format
>> quite simply. Can someone point me in the right direction please ?
>
>Although I don't have source code to offer you (you can find some easily
>with a search), You might wish to consider Huffman encoding, and
>arithmetic encoding algorithms. If you want things much better than
>those, I would suggest using a pre-built library. The code *in* the
>library might not look like 'clean source code', but the interface
>should be clean enough to use.
>
>Also, don't you mean
>BOOL ReadFileCompressed(HANDLE sfile,byte *Rbyte)
>BOOL WriteFileCompressed(HANDLE sfile,byte Wbyte)
>instead of
>> BOOL ReadFileCompressed(HANDLE sfile,byte Rbyte)
>> BOOL WriteFileCompressed(HANDLE sfile,byte *Wbyte)
>?
>
>PS, for any future followups, please remove the "sci.crypt" from the
>groups to send to, and only go to comp.compression, and the person
>you're replying to.
------------------------------
From: zapzing <[EMAIL PROTECTED]>
Subject: Re: Steganography books
Date: Mon, 23 Oct 2000 16:20:30 GMT
In article <[EMAIL PROTECTED]>,
[EMAIL PROTECTED] (wtshaw) wrote:
> In article <[EMAIL PROTECTED]>,
> [EMAIL PROTECTED] (CryptoBooks) wrote:
> ...
> >
> > The following book was the primary reference for the remarkable, and
> > well-received talk by photon (David Smith) at the ACA convention in
Providence
> > two months ago. The techniques of steganography were cleverly
demonstrated by
> > hiding, and retrieving a picture of the conference host inside
another digital
> > image.
> >
> Although the image was recoverable from the electronic image file, it
was
> not from the printed image. One question I am now working on is to
what
> extent images can store *recoverable* hidden data in a printed form,
> variations not noticable to the handler of the print, but obvious to a
> scanner. The problem is not as simple as it appears since chemical
inks
> retransmit several spectral lines, and inks vary, and scanners
vary...lots
> to learn here, and image processing can be another source of
variables.
> --
> 52) *Part of job is making whimsical, zippy, and vexing key sequences.
>
Actuall since inked or uninked paper is a
solid, the term "spectral lines" doesn't
really even apply, since solids generally
do not have spectral lines, but rather
retransmit over a continuous region of the
spectrum.
--
Void where prohibited by law.
Sent via Deja.com http://www.deja.com/
Before you buy.
------------------------------
Date: Mon, 23 Oct 2000 17:28:13 +0100
From: Richard Heathfield <[EMAIL PROTECTED]>
Subject: Re: Huffman stream cipher.
"SCOTT19U.ZIP_GUY" wrote:
>
> >Here is the output I got:
> >
> >D:\alldata\dev\crypto\scott19u>gcc -W -Wall -ansi -pedantic scott19u.c
> >In file included from scott19u.c:8:
>
> I see your mistake. you should have used
> gcc -O3 scott19u.c -o scott19u.exe
> then it will work.
You mean, "turn off all the warnings so that the compiler won't tell me
how crap the code is, and turn off all the portability flags so that the
compiler won't tell me that this code is as portable as Mount Everest"?
Okay, let's try that:
D:\alldata\dev\crypto\scott19u>gcc -O3 scott19u.c -o scott19u.exe
scott19u.c: In function `main':
scott19u.c:58: warning: return type of `main' is not `int'
So, even when I turn off all the warnings and all the portability flags,
I /still/ don't get a clean compile.
That, sir, is lame.
> Yes the "long long" type is not standard
> blessed C
Well, not in the 1990 Standard, anyway. (A newer standard supports long
long, but is so new that there are no known compilers supporting it yet,
so long long will not be portable for a year or so, at a guess.)
> but it is stadard DGJPP GNU C to get use of
> 64 bit chunks of data.
I had no idea that there was an ISO DJGPP Standard. You have a
reference?
> GNU seems to have many advanced features
> that allows one to do things normal C lacks.
Yes - most compilers do. They're called 'extensions', and the reason
they're extensions rather than core C is that they're not portable.
> I most also say that this did not compile on my original
> 486 intel PC I had to ship it encryped to my son to get it
> to compile. But on my new machine a K6-III no problem. So if
> you have low memory it will run out of space during compile.
Why's that? Let's see: Ah yes, it's probably that 1.2 Megabyte buffer.
Seems like an odd size for a buffer, but I expect you'll explain that
when you document the algorithm. And you'll have to, if you want to be
taken seriously - because the source code is, quite simply, illegible.
--
Richard Heathfield
"Usenet is a strange place." - Dennis M Ritchie, 29 July 1999.
C FAQ: http://www.eskimo.com/~scs/C-faq/top.html
66 K&R Answers: http://users.powernet.co.uk/eton/kandr2/index.html (31
to go)
------------------------------
From: [EMAIL PROTECTED] (Scott Craver)
Subject: SDMI announcement
Date: 23 Oct 2000 16:34:21 GMT
Hello,
If you read Salon or Slashdot, you may have already read
of this. Our research group, comprising of crypto-folk
from Princeton U, Rice U and Xerox have issued a press
release and faq (http://www.cs.princeton.edu/sip/sdmi/)
detailing comprehensive success in the 1st round of the
SDMI challenge.
Basically, we got positive results from the oracles
for all four watermarking technologies. These oracles
would yield a positive result if music submitted to
it was modified enough that a watermark could not be
detected, and if quality was good enough relative to
64Kbps MP3 compression. We don't know how they measured
quality. But we passed all four oracles, and repeated
our results as much as we could before the challenge
deadline was over.
A full technical writeup is coming soon, as we plan
on sharing all our findings with the cryptographic and
steganographic community. This is part of the reason
we are not participating in the second phase: we
are not interested in the prize money, and at this
point the challenge is more like a contest, providing
no real value to us from a scientific perspective.
Further participation may also restrict our ability
to publish our results---to be eligible for the prize,
it appears one must sign a form transferring intellectual
property rights to the analysis.
Finally, if you are also a research team who has
received positive results from SDMI oracles, we'd love
to hear about it. We are making a list of links to
others who have received positive results in the first
round. Keep in mind that if you're going after the
money, you might become ineligible if you publicize
these details.
-Scott
[Here's the official statement, as found at the URL:]
===============================================================
Statement Regarding the SDMI Challenge
The Secure Digital Music Initiative (SDMI) is developing a
comprehensive system to prevent music piracy. Central to this
system is watermarking, in which an inaudible message is hidden
in music to provide copyright information to devices like MP3
players and recorders. Devices may then refuse to make copies of
pieces of music, depending on the meaning of the watermark
contained therein.
In September 2000, SDMI issued a public challenge to help them
choose among four proposed watermarking technologies. During the
three-week challenge, researchers could download samples of
watermarked music, and were invited to attempt to remove the
secret copyright watermarks.
During the challenge period, our team of researchers, from
Princeton University, Rice University, and Xerox, successfully
defeated all four of the watermarking challenges, by rendering
the watermarks undetectable without significantly degrading the
audio quality of the samples. Our success on these challenges
was confirmed by SDMI's email server.
We are currently preparing a technical report describing our
findings regarding the four watermarking challenges, and the two
other miscellaneous challenges, in more detail. The
technical report will be available some time in November.
This statement, a Frequently Asked Questions document, the full
technical report (when it is ready), and other related information
can be found on the Web at http://www.cs.princeton.edu/sip/sdmi.
For more information, please contact Edward Felten at
(609) 258-5906 or felten0x40cs0x2Eprinceton0x2Eedu.
[Editor's note: replace 0x40 with '@' and 0x2E with '.']
================================================================
Scott Craver, Patrick McGregor, Min Wu, Bede Liu
Dept. of Electrical Engineering, Princeton University
Adam Stubblefield, Ben Swartzlander, Dan S. Wallach
Dept. of Computer Science, Rice University
Drew Dean
Computer Science Laboratory, Xerox Palo Alto Research Center
Edward W. Felten
Dept. of Computer Science, Princeton University
------------------------------
From: "Falissard" <[EMAIL PROTECTED]>
Subject: Re: ---- As I study Rinjdael...
Date: Mon, 23 Oct 2000 18:47:16 +0200
Reply-To: "Falissard" <[EMAIL PROTECTED]>
No, it uses the CFB mode.
See for example :
http://www.gnupg.org/rfc2440-12.html
"SCOTT19U.ZIP_GUY" wrote
> But I think PGP uses the OFB mode so I think one
------------------------------
From: James Felling <[EMAIL PROTECTED]>
Subject: Re: On block encryption processing with intermediate permutations
Date: Mon, 23 Oct 2000 12:00:46 -0500
Perhaps I can help. I think I understand Mr. Olson's method, and I also
think I may see the root of your objection.
Proposed. Submit a block of form (u,v) to the code. out will come block
(x,y) at the end.
Attn Mok:
If the PRNG's output is not keyed somehow to block number/message
length then by repeatedly doing this single encryption. what will
happen is that the set of all possible single block encryptions of (u,v)
will be eventually generated. Similary by submitting a double block one
may access a set of blocks that will allow you to identify special pairs
of blocks from the 1 block stream. Your system falls in this case.
Attn Brian:
There will be only 1 possible output of a 1block encryption if the PRNG
is keyed to block number/message length. ( i.e. all n block messages are
permuted the same way( under the same keying).)
However, in this case one may have a chance (on casual examination) of
seperating the permutation off of the code via some form of differential
attack.
------------------------------
From: James Felling <[EMAIL PROTECTED]>
Subject: Re: How about the ERIKO-CHAN cipher?
Date: Mon, 23 Oct 2000 12:07:37 -0500
"Douglas A. Gwyn" wrote:
> James Felling wrote:
> > Yes. I think that they could.
>
> The biggest flaw is that each message requires a new key.
Agreed.
------------------------------
From: James Felling <[EMAIL PROTECTED]>
Subject: Re: My comments on AES
Date: Mon, 23 Oct 2000 12:14:58 -0500
I believe that given any of the Candidates being declared the AES. There
will exist an accademic attack versus that cypher before 2006. It is
simply a matter of enough effort being applied against it. I do not
believe that any cypher can hold against that kind of attention without
some minor flaw being found. I have a feeling that this is what Bruce is
thinking as well.
Tim Tyler wrote:
> Stephen M. Gardner <[EMAIL PROTECTED]> wrote:
> : Runu Knips wrote:
> :> Bruce Schneier wrote:
>
> :> > http://www.counterpane.com/crypto-gram-0010.html#8
> :>
> :> Seems to me that Schneier also believes Rijndael is breakable.
>
> : Let's read what he actually said: [snip]
>
> : Now what makes you think that he said it was breakable.
>
> How about the bit where he wrote (from the URL above):
>
> ``I believe that within the next five years someone will discover an
> academic attack against Rijndael.''
>
> ...?
> --
> __________ http://alife.co.uk/ http://mandala.co.uk/
> |im |yler [EMAIL PROTECTED] http://hex.org.uk/ http://atoms.org.uk/
------------------------------
From: Mok-Kong Shen <[EMAIL PROTECTED]>
Subject: Re: Hypercube/FFT encryption
Date: Mon, 23 Oct 2000 19:33:03 +0200
Benjamin Goldberg wrote:
>
[snip]
> PS to Ritter, in one of your docs, you say that with 1 plaintext /
> ciphertext pair, you can probably uniquely identify a DES key... I
> believe the actual number required is 3 pt/ct pairs.
I am interested to know the reasoning behind that (either
1 or 3).
Thanks.
M. K. Shen
------------------------------
From: Mok-Kong Shen <[EMAIL PROTECTED]>
Subject: Re: What is meant by non-Linear...
Date: Mon, 23 Oct 2000 19:38:36 +0200
"Stephen M. Gardner" wrote:
>
> Mok-Kong Shen wrote:
>
> > "Stephen M. Gardner" wrote:
> > >
> >
> > > A better definition might be a transformation T is linear if T(x+y) = T(x) +
> > > T(y) and T(ax) = aT(x). The equation y = 2x over GF(3) satisfies this
> > > criterion but doesn't lie on a line in a Cartesian coordinate system.
> >
> > I understand this to mean that linearity is with respect
> > to the ring. Now it follows that 'linearity' without
> > qualification is fuzzy and hence 'non-linearity' without
> > qualification is also (perhaps more) fuzzy. Or do I miss
> > something?
>
> Well, actually, definitions of a linear space require a field not a ring. If
> the 'multiplication' isn't abelian and doesn't support an inverse then it's not a
> very fun space to play in. ;-)
But if multiplication is commutative and there is inverse
excepting for 0, then the space is more 'rich' in some
sense, isn't it?
M. K. Shen
------------------------------
From: Steven Wu <[EMAIL PROTECTED]>
Subject: Finding Sample implementation for DES and IDEA
Date: Mon, 23 Oct 2000 17:32:52 GMT
Hi everyone,
I am a student and currently interesting in block ciphers. Could
anyone tell me where to find source code for these two standards ?
Thanks in advance.
-Steven
[EMAIL PROTECTED]
Sent via Deja.com http://www.deja.com/
Before you buy.
------------------------------
From: jungle <[EMAIL PROTECTED]>
Subject: Re: SDMI announcement
Date: Mon, 23 Oct 2000 13:54:41 -0400
bravo to all you people ...
excellent attitude ...
Scott Craver wrote:
>
> Hello,
>
> If you read Salon or Slashdot, you may have already read
> of this. Our research group, comprising of crypto-folk
> from Princeton U, Rice U and Xerox have issued a press
> release and faq (http://www.cs.princeton.edu/sip/sdmi/)
> detailing comprehensive success in the 1st round of the
> SDMI challenge.
>
> Basically, we got positive results from the oracles
> for all four watermarking technologies. These oracles
> would yield a positive result if music submitted to
> it was modified enough that a watermark could not be
> detected, and if quality was good enough relative to
> 64Kbps MP3 compression. We don't know how they measured
> quality. But we passed all four oracles, and repeated
> our results as much as we could before the challenge
> deadline was over.
>
> A full technical writeup is coming soon, as we plan
> on sharing all our findings with the cryptographic and
> steganographic community. This is part of the reason
> we are not participating in the second phase: we
> are not interested in the prize money, and at this
> point the challenge is more like a contest, providing
> no real value to us from a scientific perspective.
> Further participation may also restrict our ability
> to publish our results---to be eligible for the prize,
> it appears one must sign a form transferring intellectual
> property rights to the analysis.
>
> Finally, if you are also a research team who has
> received positive results from SDMI oracles, we'd love
> to hear about it. We are making a list of links to
> others who have received positive results in the first
> round. Keep in mind that if you're going after the
> money, you might become ineligible if you publicize
> these details.
>
> -Scott
>
> [Here's the official statement, as found at the URL:]
>
> ---------------------------------------------------------------
> Statement Regarding the SDMI Challenge
>
> The Secure Digital Music Initiative (SDMI) is developing a
> comprehensive system to prevent music piracy. Central to this
> system is watermarking, in which an inaudible message is hidden
> in music to provide copyright information to devices like MP3
> players and recorders. Devices may then refuse to make copies of
> pieces of music, depending on the meaning of the watermark
> contained therein.
>
> In September 2000, SDMI issued a public challenge to help them
> choose among four proposed watermarking technologies. During the
> three-week challenge, researchers could download samples of
> watermarked music, and were invited to attempt to remove the
> secret copyright watermarks.
>
> During the challenge period, our team of researchers, from
> Princeton University, Rice University, and Xerox, successfully
> defeated all four of the watermarking challenges, by rendering
> the watermarks undetectable without significantly degrading the
> audio quality of the samples. Our success on these challenges
> was confirmed by SDMI's email server.
>
> We are currently preparing a technical report describing our
> findings regarding the four watermarking challenges, and the two
> other miscellaneous challenges, in more detail. The
> technical report will be available some time in November.
>
> This statement, a Frequently Asked Questions document, the full
> technical report (when it is ready), and other related information
> can be found on the Web at http://www.cs.princeton.edu/sip/sdmi.
>
> For more information, please contact Edward Felten at
> (609) 258-5906 or felten0x40cs0x2Eprinceton0x2Eedu.
>
> [Editor's note: replace 0x40 with '@' and 0x2E with '.']
>
> ----------------------------------------------------------------
>
> Scott Craver, Patrick McGregor, Min Wu, Bede Liu
> Dept. of Electrical Engineering, Princeton University
>
> Adam Stubblefield, Ben Swartzlander, Dan S. Wallach
> Dept. of Computer Science, Rice University
>
> Drew Dean
> Computer Science Laboratory, Xerox Palo Alto Research Center
>
> Edward W. Felten
> Dept. of Computer Science, Princeton University
------------------------------
From: Bryan Olson <[EMAIL PROTECTED]>
Subject: Re: On block encryption processing with intermediate permutations
Date: Mon, 23 Oct 2000 17:47:44 GMT
Mok-Kong Shen wrote:
> I have to understand you stuff step by step.
> So let me ask questions of the very first part (and later
> on in another post about the remaining part). What do you
> mean by having the 'first five permutations preserve block
> equality'? I mean (1) What is preservation of block equality
It means that assuming the blocks are equal before the
permutation, then they are equal after the permutation.
I see I switched notation mid-sentence in one explanation, so
here's the fixed version: Suppose the two blocks going into
a permutation are the same; say the words are (x, y, x, y).
Eight of the 24 permutations keep the two blocks the same,
four of them producing (x, y, x, y), and four producing
(y, x, y, x).
> and (2) How can the opponent achieve that since he has no
> control at all of the PRNG.
He encrypts repeatedly so it happens at random. The attack
explains how he can tell when it did happen.
--Bryan
Sent via Deja.com http://www.deja.com/
Before you buy.
------------------------------
From: jungle <[EMAIL PROTECTED]>
Subject: Re: How to post absolutely anything on the Internet anonymously
Date: Mon, 23 Oct 2000 14:00:38 -0400
Andre van Straaten wrote:
>
> In sci.crypt Anthony Stephen Szopa <[EMAIL PROTECTED]> wrote:
> > How to post absolutely anything on the Internet anonymously
>
> > http://www.sciam.com/2000/1000issue/1000techbus2.html
===
> But if someone is tapping your modem or cable line, or your ISP, too,
> they can see everything you send,
"can see", yes but not know what it is, yes ...
someone [ sorry not you ... ] can post ANON even the above has been said
------------------------------
From: Mok-Kong Shen <[EMAIL PROTECTED]>
Subject: Re: On block encryption processing with intermediate permutations
Date: Mon, 23 Oct 2000 20:14:40 +0200
James Felling schrieb:
>
> Perhaps I can help. I think I understand Mr. Olson's method, and I also
> think I may see the root of your objection.
>
> Proposed. Submit a block of form (u,v) to the code. out will come block
> (x,y) at the end.
>
> Attn Mok:
> If the PRNG's output is not keyed somehow to block number/message
> length then by repeatedly doing this single encryption. what will
> happen is that the set of all possible single block encryptions of (u,v)
> will be eventually generated. Similary by submitting a double block one
> may access a set of blocks that will allow you to identify special pairs
> of blocks from the 1 block stream. Your system falls in this case.
Yes, all possible blocks will eventually be generated with
a fairly good chance, if one encrypts a very long message
with each block the same (u,v). So one can get a set of
possible blocks on the ciphertext side. With 8 cycles this
set is likely to be not too small and hence the message
length. One point I don't yet understand is how to pick
a 'particular' subset from that set that promises to well
deliver information about the key and moreover what is the
chance of picking that. Could you help me a bit on that?
Thanks in advance.
M. K. Shen
------------------------------
From: Mok-Kong Shen <[EMAIL PROTECTED]>
Subject: Re: Finding Sample implementation for DES and IDEA
Date: Mon, 23 Oct 2000 20:17:30 +0200
Steven Wu wrote:
>
> I am a student and currently interesting in block ciphers. Could
> anyone tell me where to find source code for these two standards ?
It is best always to try first to consult standard textbooks.
Schneier's book has the codes.
M. K. Shen
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