Cryptography-Digest Digest #756, Volume #12 Sat, 23 Sep 00 17:13:00 EDT
Contents:
Re: What make a cipher resistent to Differential Cryptanalysis? (Tom St Denis)
Re: Software patents are evil. (Jerry Coffin)
Re: Music Industry wants hacking information for cheap (zapzing)
Re: t (zapzing)
Re: t (zapzing)
Re: Music Industry wants hacking information for cheap (Sagie)
Re: Big CRC polynomials? (Paul Schlyter)
Re: What am I missing? (Sagie)
----------------------------------------------------------------------------
From: Tom St Denis <[EMAIL PROTECTED]>
Subject: Re: What make a cipher resistent to Differential Cryptanalysis?
Date: Sat, 23 Sep 2000 19:18:16 GMT
In article <[EMAIL PROTECTED]>,
Mok-Kong Shen <[EMAIL PROTECTED]> wrote:
>
>
> "David C. Barber" wrote:
> >
> > DES, for example is considered resistant to Differential
Cryptanalysis,
> > particularly in its selection of S-boxes. What about them, or any
cipher,
> > makes it DF resistant?
>
> I believe that one good way is to arrage to have the
> S-boxes of the cipher be all different and to have
> them either key-dependent or fixed but having their
> ordering dependent on the key. I like to know references
> to analysis results for such situations, if any.
That's not entirely correct. It's possible to have random key
dependent sboxes and still be vulnerable to attacks.
Tom
Sent via Deja.com http://www.deja.com/
Before you buy.
------------------------------
From: Jerry Coffin <[EMAIL PROTECTED]>
Subject: Re: Software patents are evil.
Date: Sat, 23 Sep 2000 13:36:56 -0600
In article <yqSy5.108$Lf5.1216@client>, [EMAIL PROTECTED]
says...
[ ... ]
> 17 years later. By that time, a new and superior algorithm will be
> patented, starting the circle over again. Oh joy.
I've already pointed out things like RSA, DH and LZW that are
obviously a LONG ways from completely obsolete.
> This is pretty funny. Name ONE time that this has EVER happened. They
> might buy a patent from you, but they won't help you enforce a patent they
> don't own.
>
> > There are a fair number of quite large companies
> > that do NOTHING but help their clients enforce patents. For one
> > example, the Mahr-Leonard Management Company has made a huge amount
> > on patent licensing. Contrary to some statements in this thread
> > though, the owners of the patents really DO make money on them -- it
> > doesn't all go to the attorneys or anywhere close to it.
>
> I would be interested in seeing some figures for small-time people or
> start-up companies to see how this really works out for "the little guy."
If you're honestly interested, go find them. I've given you the name
of one company to look at. Assuming you have an IQ above room
temperature, it'll be incredibly easy for you to find out that most
of what you've been saying is wrong. There's only so far I can go in
providing you the information, and a bit less far I'm willing to go.
I suppose I could plug the company name into Yahoo!, Google, Alta
Vista, etc., and find you a plethora of URLs, but I doubt it would
make any real difference: if you're not willing to do that tiny bit
on your own, then the hard part of actually reading and understanding
what they say is obviously far more than you'll bother with. I
already understand what's going on, but my re-reading things I
already know isn't going to suddenly make YOU understand more than
you do now.
> In my experience working as a subcontractor and as an employee, the firms I
> have worked for have never bothered to try and patent anything.
Okay. What of it?
> I will admit that there have been compelling arguments that I had not
> thought of to support patents. I still think they are evil, and here's why:
>
> "Back in the day" (I've been a programmer a long time) people used to invent
> algorithms and just publish them in the ACM. No patent, no secrecy, no
> nothing. "Lookie! A new algorithm! Here is the explanation. Have fun."
> Now, back in those days, algorithms exploded like a bomb blast going off.
>
> With the heavy advent of patents (and even copyrights for that matter) that
> has really simmered down.
This has nothing to do with patents at all. The simple fact is that
if (for example) you wanted to sort some things in a computer in
1948, you invented an algorithm to do it. You quickly noticed that
your 10 KHz CPU took a long time to sort much using your lousy first
attempt at a sorting algorithm. Therefore, you set out to invent
something better, and quickly did so.
For better or worse, the Quicksort has long-since been invented and
enough theory has been studied that we know a sort in the normal
sense of the word can't get a lot better than the Quicksort already
is, at least in the average case.
New algorithms DO still get invented; consider the Introsort, which
was invented quite recently. It improves on the Quicksort by
guaranteeing that the worst case is still O(N lg N). If this had
happened 30 years ago, it would have been MAJOR news, but nowadays
sorting is rarely enough of consequence that most programmers haven't
noticed it at all.
New algorithms now tend to be in more specialized niches where CPU
speed still isn't adequate to render algorithmic improvements
meaningless. Gamers routinely invent new graphics rendering
algorithms, but unless you happen to be a gamer, you probably don't
care. Hardware is improving so fast that I don't expect this to last
a lot longer either though.
Most people lack incentive to invent new algorithms, especially in
fundamental areas where most of us would notice them. Most of the
time, they can easily use a canned algorithm in their standard
library. Even if they had a wonderful new idea, it would take little
short of a miracle for it to be much more than slightly better than
existing ones for most of the really fundamental operations, so even
when it does happen, it means very little.
None if this, though, has ANYTHING to do with patents or even
copyrights. To give another example, you could say essentially the
same thing about automobiles, but with a different time frame. 100
years ago, everybody who built a horseless carriage invented a new
placement for the brake pedal, a different way for shifting to work,
and so on. Automobiles have progressed to the point that all of this
is now well standardized, and manufacturers desperate for anything to
separate themselves from the field call 1% adjustments revolutionary,
and do things like inventing tail fins, side scoops, etc., because
they haven't had a substantive new invention in 20 years or so...
--
Later,
Jerry.
The Universe is a figment of its own imagination.
------------------------------
From: zapzing <[EMAIL PROTECTED]>
Subject: Re: Music Industry wants hacking information for cheap
Date: Sat, 23 Sep 2000 19:44:15 GMT
In article <8qg03r$fak$[EMAIL PROTECTED]>,
[EMAIL PROTECTED] (Scott Craver) wrote:
> zapzing <[EMAIL PROTECTED]> wrote:
>
> > These so called technological methods of protecting a copyright are
the
> > purest of fiction. At some point it must be converted into sights
and o
> > sounds so that a Human can enjoy them. At that point, just record it
> > and copy it as much as you wish.
>
> False! That's the whole point of audio watermarking: it's
> not encryption. Even when the media is converted to "sights
> and sounds" (i.e., unscrambled/unencrypted) and played on your
> TV and stereo, the watermark is still hidden inside it.
> At that point, if you try to record the audio, right from your
> amp's line out into an SDMI-compliant recording device, the
> device will still refuse to record it. Unless you strip out
> the hidden signal, which for the time being requires a piece
> of software which would be illegal to own or distribute.
<sarcasm>
Oh that's cool. So If I want to shut down the
surveillance cameras at the bank all I would
have to do is play a DVD movie in front of it
and it would refuse to record right ?
How about I just put a protected
picture on my T-shirt, then nobody
could photograph me ! Cool!
<\sarcasm>
So do you really beieve that *all* of
the recording, copying, and playing equip.
will be SDMI compliant ??? What if I want to
put a private surveillance camera in my
own house ???
>
> >Unless if you think that they are going to put one of their
DVD-whatever-
> >things into every camcorder in the world. LOL.
>
> Presumably, anything that records _onto_ a DVD from a line in
> will have a watermark detector. I don't know what they will
> try to do for other kinds of digital media such as DV tapes.
> For a camcorder there shouldn't be a problem, unless the
> camcorder has a line input rather than just a lens input.
>
> If that sounds ridiculous, I can't disagree. But people who
> control various patents can enforce compliance among device
> manufacturers.
>
That the entertainment industry has a right to
protect it's patents, I agree. That they have a
right to protect them in this way, which would
be so intrusive into people's lives that it's
ridiculous, I disagree.
--
Void where prohibited by law.
Sent via Deja.com http://www.deja.com/
Before you buy.
------------------------------
From: zapzing <[EMAIL PROTECTED]>
Subject: Re: t
Date: Sat, 23 Sep 2000 19:45:55 GMT
In article <[EMAIL PROTECTED]>,
[EMAIL PROTECTED] wrote:
>
> Fortunately, the self destruct button is completely unlabeled and
looks just
> like every other button on the console. Uh huh. 8-O
>
Sounds like something NASA would design.
--
Void where prohibited by law.
Sent via Deja.com http://www.deja.com/
Before you buy.
------------------------------
From: zapzing <[EMAIL PROTECTED]>
Subject: Re: t
Date: Sat, 23 Sep 2000 19:55:41 GMT
In article <[EMAIL PROTECTED]>,
[EMAIL PROTECTED] wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
>
> zapzing wrote:
> > In article <8qcise$l6i$[EMAIL PROTECTED]>,
> > [EMAIL PROTECTED] (Thomas Pornin) wrote:
> > > There is also the classical "Stranded on Venus" problem: some
> > > scientists have a technical problem on the ground of planet Venus.
> > > To get back to the orbital station, a button must be pushed on the
> > > control panel of the station, but there is nobody left to push
that
> > > button... except some bypassing (and altogether cooperative)
aliens.
> > >
> > > The scientists manage to establish a radio communication with the
> > > aliens, and build up some sort of language (they are *good*
> > > scientists).
> > > But the main problem is that there are two buttons on the panel.
The
> > > left one is the one to be pushed. The other one is the
self-destruct
> > > command.
> > >
> > > How will the scientists and aliens agree on the notion of left and
> > > right ?
> >
> > OK, Helpful Aliens. Just take a look at the third planet
> > from this here star. It's got a Nitrogen, Oxygen atmosphere
> > with a bunch of other neat stuff. The "northern" hemisphere
> > is the one with most of the land masses on it. If you are
> > standing with your back to the sun, and looking at Earth
> > (the third planet) with your head pointing north, and your
> > feet pointing south (opposite of north) then a point on the
> > planet on the sunny side will be moving left to right (or
> > is it right to left?).
>
> Head? Back? Feet? The aliens don't have those.
Presumably the good Venusian scientist will be
able to communicate these thiings to the good
helpful alien scientists, since they were after
all able to describe what a sattellite, control
panel, and button is.
> A simpler approach is to draw a 2D schematic picture of the control
> panel and buttons from the point of view of someone looking at it,
> digitise that picture (neglecting rotations, there are two ways of
> serialising a 2D pixellated image, and if the control panel has no
> bilateral or rotational symmetry, the aliens can determine which one
> has been used), and transmit the digitised picture over the radio.
> That would probably even work even if you hadn't first established a
> language.
>
> If the control panel is bilaterally symmetrical, send a picture of
> something else that isn't symmetrical as a reference, e.g. the
> Earth, or an experiment demonstrating the left-hand rule in
> electromagnetism. (If the panel and the spaceship are rotationally
> symmetrical, it's not just the aliens who will have problems :-)
Yes that was pretty much my idea since the Earth is not
symmetrical. A "Macrocosmic" approach as opposed to a
microcosmic approach. Presumably the scientists would
use both to make sure. Or maybe not, I have to remember
these are NASA scientists. Stupid Geniuses.
> Nothing in this message is intended to be legally binding. If I revoke
a
> public key but refuse to specify why, it is because the private key
has been
> seized under the Regulation of Investigatory Powers Act; see
www.fipr.org/rip
>
Actually the steganographic communication
of a single bit is much easier than that.
You are relying on PKP, here.
--
Void where prohibited by law.
Sent via Deja.com http://www.deja.com/
Before you buy.
------------------------------
From: Sagie <[EMAIL PROTECTED]>
Subject: Re: Music Industry wants hacking information for cheap
Date: Sat, 23 Sep 2000 20:00:05 GMT
> > So I suppose your one of those guys that actually do acquire
DVDs from
> >your own region alone? ;)
>
> No, haven't yet tried a DVD (I get my entertainment from USENET)
> but just study watermarking systems.
I was trying to make a point using cynicism. The DVD-video
specifications restrict content according to regions. Every DVD
manufacturer is theoretically supposed to enforce the DVD player's
region and match it with the disc's region. In reality, this does not
always happen.
> > Seriously now, any type of content restriction that has been
presented,
> >to this date, is already defeated/ignored. I suppose you did not
know this,
>
> But this says nothing about future security systems.
But that was exactly my point! I say -- considering past experience,
any digital content restriction method is doomed to be futile.
> The fact is
> that, if someone who controls the patents to a media technology
want
> a security feature honored, it will be honored. This is the
case
> with DVD watermarking: when it's ready for deployment, makers
of
> DVD recorders will not be allowed to ignore them, if they want
> to be allowed to legally build DVD recorders.
As I said earlier in this post, DVD-video specs define a security
feature (regions). The fact is that it is not always honored.
> Defeating content restrictions is a different matter. The main
> problem of piracy prevention is that it must usually be a public
> scheme, so all the devices in the world can read your disk.
> This approach has been used and defeated ever since personal
> computers existed.
Defeating content restriction has nothing to do with computers. When
the scheme is publicly available, it is available to pirates as well.
> However, the industry is most concerned about "common case"
theft.
> If you prove that a hacking tool can bypass a security system,
> at least in pre-DMCA days, you'd often get the response that
anyone
> downloading a hacking tool is not a common case. That most
> consumers will just have black boxes made by Panasonic or Sony,
> and they won't use this hacking tool.
First of all, I don't know what DMCA is. Secondly, in the information
age there is no such thing as a common case. I suppose RIAA thought
that in the common case people would not download music as MP3s (well
they sure were wrong, weren't they?).
> > Besides, if manufacturers would actually go through this, you
can be
> >certain that SDMI-signal-defeaters would arise, and that your local
> >electronics repairman would happily re-arrange the internal
circuitry of any
> >SDMI compliant player you would give to him.
>
> This could be the case if (when?) that one part of the DMCA is
> ruled unconstitutional. Until then, your electronics repair-
> person is at risk when doing something like this.
Again, I have no idea what DMCA is. My electronics guy could not be at
risk for manipulating the internal circuitry of a device I own, at my
request (unless you are talking about some kind of a totalitarian
regime).
> Also, the more monolithic things get, the harder it is for
> people to bypass a security feature. If there's a chip
somewhere
> on the mainboard which outputs a 1 or 0 to refuse to copy an
audio
> clip, okay, that's easy. But what happens when you have a
single
> chip with decompression and watermark detection integrated
together?
Well yeah, but nowadays if there is one chip that does everything, it
is usually a DSP. If it is a DSP then it runs software -- that software
can be cracked. For example, I bought a DVD drive so that I could play
DVDs on my computer. The DVD drive had internal region protection,
which would have prohibited me from watching content from outside my
region. All I had to do was go on line and in no time I found a "fixed"
firmware (for that exact DVD drive model) that defeats the region
protection.
Sent via Deja.com http://www.deja.com/
Before you buy.
------------------------------
From: [EMAIL PROTECTED] (Paul Schlyter)
Subject: Re: Big CRC polynomials?
Date: 23 Sep 2000 21:11:11 +0200
In article <[EMAIL PROTECTED]>,
Runu Knips <[EMAIL PROTECTED]> wrote:
> Paul Schlyter wrote:
>> In article <8qgg1h$pmc$[EMAIL PROTECTED]>, <[EMAIL PROTECTED]> wrote:
>>> I'm seeking good 128- and 256-bit CRC polynomials. I've done a bit of
>>> searching about on the net and have only been able to locate commonly used
>>> polynomials of 32 and fewer bits. My intention is to use either a 128- or
>>> 256-bit polynomial for the purpose of uniquely identifying large numbers
>>> (millions) of binary files; consequently, a 32-bit CRC is probably a bit too
>>> small for this purpose.
>>>
>>> Can anybody point me in the direction of some big polynomials to use for this
>>> purpose? I could just randomly generate a polynomial for this purpose but if
>>> somebody has/knows a "good" polynomial of this size it would be most helpful.
>>> I unfortunately don't have the expertise nor the time necessary to develop
>>> sufficient expertise to write polynomial generation routines which will pick
>>> "good" polys.
>>
>> Why not use MD5 or SHA instead? They produce hashes of 128 resp 140 bits,
>
> (160 bit, not 140)
Yes, that's right.
>> they're very well tested, and they would be excellent for this purpose.
>> Free C source for MD5 and SHA are available from many places on the Net.
>
> Tiger from Eli Biham (http://www.cs.technion.ac.il/~biham/) should also
> be mentioned at this place. According to Biham, it is as fast as SHA-1
> on 32-Bit machines, and faster in all different environments, especially
> on 64 Bit ones.
>
> Tiger produces 196 bits of output. It is very young but I think for this
> case it doesn't matter, because even if someone would break it it will
> still fit the requirements for that purpose.
>
> However, IMHO a cryptographically hard hashsum is a little bit too much
> for this purpose.
In principle true, however implementations of these hashsums are readily
available, while a 128-bit or 256-bit CRC is not.
--
================================================================
Paul Schlyter, Swedish Amateur Astronomer's Society (SAAF)
Grev Turegatan 40, S-114 38 Stockholm, SWEDEN
e-mail: pausch at saaf dot se or paul.schlyter at ausys dot se
WWW: http://hotel04.ausys.se/pausch http://welcome.to/pausch
------------------------------
From: Sagie <[EMAIL PROTECTED]>
Subject: Re: What am I missing?
Date: Sat, 23 Sep 2000 20:46:38 GMT
> SDMI is a security initiative for digital music that
incorporates
> watermarking, along with other stuff. Watermarking is important
> for its security, because a main goal of the initiative is to
> identify stolen music long after it's been ripped, and perhaps
> converted to various formats.
Taken from the SDMI FAQ:
Q - Does the SDMI specification designate particular technologies?
A - SDMI is an architectural framework, and is not intended to specify
particular technological choices (such as compression or encryption
technologies). But there are some components of the system that may
require the designation of a particular technology. The Phase
1 "screen" technology is such a component.
*** end of quote ***
As stated in the FAQ, the SDMI specifications specifies an
architectural framework and a screening technology. Screening (in this
case) means applying and detecting watermarks. The architectural
framework creates a concept known as "SDMI domain", protected by the
screening technology. The screening prevents any illegal content to
enter the SDMI domain. Since SDMI specification do not replace the
actual medium of music transfer, the base of SDMI is, eventually, the
watermark. The "other stuff", as you put it, is mainly detecting the
watermark, detecting its contents, and enforcing content restriction
rules.
> Funny fact: SDMI does not just include inaudible "don't copy
me"
> signals, but also inaudible "don't copy me if I'm compressed,
> or have ever been compressed in the past" signals. This is an
> attempt to quash MP3 piracy in particular: you will be able
> to rip a CD track into an SDMI device you can take jogging,
> but not a downloaded MP3.
Funny fact: most music compressors nowadays are based on advanced
psycho-acoustic models. In plain english it means that compression is
achieved by removing inaudible information. The SDMI watermark is
supposedly inaudible, but it is also supposedly resistent to MP3
compression (which is based on a psycho-acoustic model). So this may
mean one (or more) of the following:
1. SDMI watermark is not truly an inaudible watermark. We are all going
to be fucked and receive screwed up music in exchange for our hardly-
earned money.
2. SDMI watermark is not truly resistent to MP3. They are trying to
scare us all and make us think that our jolly MP3 days are over, but
they're really not.
3. SDMI watermark might slip through MP3 compression, but it really has
no chance of resisting an advanced futuristic compression, whose nature
is unknown at the time of designing the current watermark technology
(i.e. *NOW*).
> Mr. Barber was right in his observation --- compliant devices
> can, if the recording industry plays its cards right, be the
> only devices manufactured that will play new formats or new
> compression codecs. They can become the "common case" players
> that the kiddies get around X-mas.
In the information age there is no such thing as a "common case". I
suppose RIAA thought that in the common case people would not download
music as MP3s (well they sure were wrong, weren't they?).
> The fact that you can always play the files on your computer,
> or on older MP3 players, might not amount to much if player
> technology really takes off and your old devices are left
> in the dust.
Yeah, but as I said before, I doubt if the SDMI watermark will resist
new technology compression. By the time SDMI-compliant players will
finally be widespread, the new compression will come out. By the time
SDMI will figure out the old watermark is no good, they'll have to
develop a new watermark and start a new campaign to embed the new
technology. Again this will take the time to catch up... and so the
story goes again...
> >Ryan -- using an audio editor (e.g. Cool Edit, Sound Forge), try
> >to "subtract" the original wave from the watermarked wave. This will
> >allow you to see the actual watermarking signal and analyse it.
>
> It will allow you to do the former but not the latter---that
> takes signal processing know-how. But then again, you gain
> that kind of know-how partially by experimenting with these
> things.
Oh yeah. You got to be a DSP wiz to click menus... NOT!
The guy can run a frequency analysis, check the stereo image, see the
magnitude level of the watermark signal, and that's only the beginning
of it (all within a couple of clicks here and there). If this is not
analysis then I don't know what is.
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Before you buy.
------------------------------
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