Cryptography-Digest Digest #983, Volume #12 Mon, 23 Oct 00 04:13:01 EDT
Contents:
Re: Visual Basic ("dlk")
Re: How to post absolutely anything on the Internet anonymously (Anthony Stephen
Szopa)
Re: Steganography books (Scott Craver)
Re: Problem with the CS-Cipher (Serge Vaudenay)
Re: Visual Basic (Guy Macon)
Re: new to data encryption please help (Dido Sevilla)
who first will break claim that DVD pattern of imprints can't be (jungle)
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From: "dlk" <[EMAIL PROTECTED]>
Subject: Re: Visual Basic
Date: Mon, 23 Oct 2000 05:54:56 GMT
Paul Schlyter wrote in message <8sua6k$s61$[EMAIL PROTECTED]>...
<snip>
>
>VB is compiled too; however VB as a language is indeed unsuitable
>for bit-twiddling.
Ain't that the truth! I've an "academic" interest in crypto, mainly I work
with process control equipment (PLC), there, bits (or a bit) state is
of primary interest. What I did was cobble up a simple win32 dll
in VC (inline asm for bt, btr, bts, shl, shr) and call them from VB
(VB used to develop the HMI).
Works ok for testing/working with "a handful", but having tried it
with more intensive "bit-twiddle" work (like SHA), one is better
off doing the whole "function" in C or ASM - like another poster
said, it's just not efficient in VB.
Dave Keever
{Email: dlkeever at hotmail.com}
------------------------------
From: Anthony Stephen Szopa <[EMAIL PROTECTED]>
Crossposted-To: talk.politics.crypto,alt.freespeech
Subject: Re: How to post absolutely anything on the Internet anonymously
Date: Sun, 22 Oct 2000 23:07:58 -0700
Tim Tyler wrote:
>
> In several places, Anthony Stephen Szopa <[EMAIL PROTECTED]> wrote:
>
> : [...] this system actually posts the data to numerous internet
> : servers where anyone can down load it while at the same time making
> : it highly unlikely that anyone, including the government, could
> : remove the information from all the servers.
>
> : While also providing to make it impossible for the server owner to
> : be held accountable since the server owner has no way of knowing
> : what is on their server since this file is encrypted.
>
> They could just make running Publis illegal. There will have to be some
> ofther compelling use for - it besides cocking a snook at the government -
> to prevent this strategy from being applied.
>
> : I am not sure, but using an anonymous service may not be required
> : but it does add another layer through which it will be very
> : difficult to trace the poster through. It was suggested that a
> : poster could use Publius while posting through a public host. This
> : would certainly anonymize the poster.
>
> 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.
------------------------------
From: [EMAIL PROTECTED] (Scott Craver)
Subject: Re: Steganography books
Date: 23 Oct 2000 06:17:16 GMT
wtshaw <[EMAIL PROTECTED]> wrote:
>
>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.
Hi,
There are a number of papers you chould check out in the 2nd/3rd
Information Hiding Workshop proceedings. Walter Bender and Daniel
Gruhl (sp?) kicked off the 2nd workshop with a paper on hiding data
in printed currency so as to be detectable by scanners. This
is marking rather than general stego (i.e., embedding 1 bit
rather than an n-bit message,) but they address some scanner/printer
issues. Also, check out Lisa Marvel's paper, where they embedded
about 5K in an image using spread-spectrum techniques. I do not
know how well this survives printing/rescanning.
In the 3rd workshop, there is a paper by Elke Franz and Andreas
Pfitzmann, which describes ways to make hidden marks resemble
scanner noise, which might be ideal for your intended application.
Also, the paper by Alessia De Rosa et al, "Optimum Decoding of
Non-additive Full Frame DFT Watermarks" in the same proceedings.
They do test their scheme by printing/xeroxing/scanning, and
their watermark does survive the detector. It's a wonderful
example of the kind of great results you can get by designing
a really good detector. That's also watermarking (1 bit) rather
than stego oriented towards sending a message.
-S
------------------------------
Date: Mon, 23 Oct 2000 08:54:20 +0200
From: Serge Vaudenay <[EMAIL PROTECTED]>
Subject: Re: Problem with the CS-Cipher
Tom St Denis wrote:
>
> I implemented the M-Function as described in CS-Cipher and I found that
> with a prob. of 65026/65536 that any two inputs (that differ by a fixed
> amount) will not be a multipermutation.
>
> Essentially I took a 16-bit input 'x' and a difference 'y' and got 'z =
> M(x) xor M(x xor y)' and counted the number of times either the low or
> high byte of 'z' is zero.
>
> Well actually I used a slightly different 'sbox' but I think the idea
> holds true.
>
> Am I mistaken or is their structure not a multipermutation?
>
> Tom
>
> Sent via Deja.com http://www.deja.com/
> Before you buy.
The multipermutation property says that you should never get a low of
high zero
byte for z whenever the low or high byte of y is zero: not for any y.
Serge
------------------------------
From: [EMAIL PROTECTED] (Guy Macon)
Subject: Re: Visual Basic
Date: 23 Oct 2000 07:10:41 GMT
Paul Schlyter wrote:
>
>Guy Macon wrote:
>
>> Paul Schlyter wrote:
>>
>>> VB is compiled too; however VB as a language is indeed unsuitable
>>> for bit-twiddling.
>>
>> PowerBASIC, on the other had, is ideal for bit-twiddling.
>> [ http://www.powerbasic.com ]. On the same subject, everyone
>> who twiddles bits should know about [ http://www.basicx.com ].
>
>Power Basic was once Borland's Turbo Basic. I see no reason why a
>Borland dialect of Basic should be so much more suitable for bit
>twiddling than a Microsoft dialect of Basic.
Then you lack knowledge. Microsoft started out somewhat GUI and
hand holding, and has gotten farter and farther from the hardware.
Power Basic started off more low level, and has gotten closer
and closer to the hardware.
> Can you, for instance,
>in Power Basic do a right shift and control whether it's to be an
>arithmetic right shift or a logical right shift? (without resorting
>to assembly language, that is). Yes, there's probalby some ugly
>way to do it, but can it be done cleanly, in one operation?
Certainly. There are keywords for bit shift and rotate, with modes
for arithmetic or logical, with and without carry, and everything
else your little heart could desire. This BASIC was made for low
level stuff like this.
>BTW Power Basic shares one weakness with Visual Basic: it's a single
>platform language, and it's hard to port such programs to other
>platforms.
Indeed. As is Visual C++ with MFC. I like 100% pure ANSI C and
Ansi C++ myself, but different languages shine in different
situations. C make a lousy Perl, for example.
The sad thing is that folks like you never got the word that there
are BASICs that are also good at things like bit twiddling.
------------------------------
From: Dido Sevilla <[EMAIL PROTECTED]>
Subject: Re: new to data encryption please help
Date: Mon, 23 Oct 2000 15:19:59 +0800
[EMAIL PROTECTED] wrote:
>
> hi
> i am a biology student with nothing whatsoever to do with encryption
> yet i have written some programs to do the same just for fun but now i
> want to learn the real methods of doing it. Can anyone please help me ?
> i would like to know any online references for beginners and if
> possible books .
Find a copy of Bruce Schneier's "Applied Cryptography". Try visiting
http://www.cacr.math.uwaterloo.ca/hac/ as well. And read the FAQ too.
There are lots of references there although admittedly it's somewhat
dated. The Counterpane website (http://www.counterpane.com/) is another
nice site with lots of useful information. They publish their research
online and it's nice to be able to study how the professionals do it.
--
Rafael R. Sevilla <[EMAIL PROTECTED]> +63 (2) 4342217
ICSM-F Development Team, UP Diliman +63 (917) 4458925
OpenPGP Key ID: 0x0E8CE481
------------------------------
From: jungle <[EMAIL PROTECTED]>
Subject: who first will break claim that DVD pattern of imprints can't be
Date: Mon, 23 Oct 2000 03:40:52 -0400
who first will break claim that DVD pattern of imprints can't be tampered with,
erased or falsified ?
Fingering the DVD Pirates
===
Benjamin Bachrach, Intelligent Automations' senior scientist, said the
DiscPrint system uses a laser sensor to build a 3-D map of the surface of the
disk, looking for the unique pattern of imprints.
"The stamping plate has some imperfections that are involuntarily transferred
to the CD itself," he said. "Just like a bullet fired from a gun."
Bachrach said that, unlike other coding technologies, the pattern of imprints
can't be tampered with, erased or falsified.
===
http://www.wired.com/news/print/0,1294,39351,00.html
------------------------------
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