Cryptography-Digest Digest #944, Volume #13 Mon, 19 Mar 01 19:13:00 EST
Contents:
Re: Are prime numbers illegal ? ("Douglas A. Gwyn")
Fast and Easy crypt send (amateur)
CNN story on NSA ("Douglas A. Gwyn")
Re: Fast and Easy crypt send (amateur)
NSA in the news on CNN ("Mxsmanic")
Re: Are prime numbers illegal ? (Sundial Services)
Re: NSA in the news on CNN (Sundial Services)
Re: Fast and Easy crypt send (Mok-Kong Shen)
Re: Fast and Easy crypt send (Sundial Services)
Re: Idea (amateur)
Signing/Not signing posts ("Joseph Ashwood")
Re: Fast and Easy crypt send (amateur)
Re: Signing/Not signing posts (amateur)
Re: My cypher system (Mok-Kong Shen)
Re: Fast and Easy crypt send (amateur)
Re: SSL secured servers and TEMPEST (Paul Rubin)
Re: NSA in the news on CNN (jtnews)
Re: One-time Pad really unbreakable? (Tim Tyler)
Re: Signing/Not signing posts (Mok-Kong Shen)
Re: OT: TV Licensing - final answer - sorry for xpost (Paul Schlyter)
Re: [OT] Why Nazis are evil (Paul Schlyter)
Re: How to eliminate redondancy? ("Joseph Ashwood")
Re: Is SHA-1 Broken? (Steve Meyer)
----------------------------------------------------------------------------
From: "Douglas A. Gwyn" <[EMAIL PROTECTED]>
Subject: Re: Are prime numbers illegal ?
Date: Mon, 19 Mar 2001 21:23:58 GMT
John Savard wrote:
> If you can't copyright items that are on the real number line, if you
> can't copyright integers, how can you copyright anything, since
> everything can be coded as a number?
I think the distinction that should be made is whether or not the
number represents proprietary information *using a published or
well-known coding*. (One can always design an ad-hoc coding that
takes a given piece of information to a given integer, but what
would constitute proof of intent would be for a single encoding
to relate several suspect integers to intelligible proprietary
plaintexts. The odds of that happening by accident could be
computed, if necessary.)
------------------------------
From: amateur <[EMAIL PROTECTED]>
Subject: Fast and Easy crypt send
Date: Mon, 19 Mar 2001 17:16:36 -0400
What if I use single function to transmit my encrypted text E
Algo Fast and Easy
Symetric keys Bob and Alice have the same key just to receive E (not to
encrypt). I suppose that they have the key to decrypt and encrypt. I'm
talking about a secure sending.
E=f(k)= a-k
Sample
E=1532 as decimal integer
k= 5421 as decimal integer
a= 6953 as decimal integer
Bob using his key "k" send "a" to Alice
The attacker ("passive attack") has only "a"
Even if he intercept "a", it will be to hard to deduce "e".
I suppose that he did intercept it. He has to decrypt it.
How he can e= a-k if he obtain only "a"? he doesnot know nor E nor k.
In reality Bob has to use a hudge number k not as my sample.
Fast and Easy?
I'm waiting for comments.
------------------------------
From: "Douglas A. Gwyn" <[EMAIL PROTECTED]>
Subject: CNN story on NSA
Date: Mon, 19 Mar 2001 21:53:25 GMT
http://www.cnn.com/SPECIALS/2001/nsa/stories/codebreakers/index.html
------------------------------
From: amateur <[EMAIL PROTECTED]>
Subject: Re: Fast and Easy crypt send
Date: Mon, 19 Mar 2001 17:18:12 -0400
I forget. Bob may use more complex function too f(k).
------------------------------
From: "Mxsmanic" <[EMAIL PROTECTED]>
Crossposted-To: comp.security.pgp.discuss,alt.security.pgp
Subject: NSA in the news on CNN
Date: Mon, 19 Mar 2001 22:35:38 GMT
CNN has a special series on the NSA (how times change!) this week, which
may generate some interest in PGP, as I presume they'll eventually get
around to mentioning the program. They are supposed to talk about
encryption in days to come, but I don't know to what extent. The series
even shows pictures from inside the NSA! Those people at Fort Meade
must be getting desperate for funding, or something!
------------------------------
Date: Mon, 19 Mar 2001 15:39:40 -0700
From: Sundial Services <[EMAIL PROTECTED]>
Reply-To: [EMAIL PROTECTED]
Subject: Re: Are prime numbers illegal ?
It is, in a word, the kind of argument that will cause a judge to smile
in a dangerous sort of way. But the entire Digital Milennium Copyright
Act is rather like that, too. It's a politically-motivated piece of
legislation if ever there was one, and between the time that the
legislation was introduced in committee and the time it made it to the
Senate floor, times had surely changed.
Part of the problem, unfortunately, is the flagrancy with which groups
like Napster violated copyrights ... and persisted in doing so. It
forced the holders of copyrights to seek extensive changes to the law,
which eventually they received, for better or for worse.
>Douglas A. Gwyn wrote:
>
> John Savard wrote:
> > If you can't copyright items that are on the real number line, if you
> > can't copyright integers, how can you copyright anything, since
> > everything can be coded as a number?
>
> I think the distinction that should be made is whether or not the
> number represents proprietary information *using a published or
> well-known coding*. (One can always design an ad-hoc coding that
> takes a given piece of information to a given integer, but what
> would constitute proof of intent would be for a single encoding
> to relate several suspect integers to intelligible proprietary
> plaintexts. The odds of that happening by accident could be
> computed, if necessary.)
==================================================================
Sundial Services :: Scottsdale, AZ (USA) :: (480) 946-8259
mailto:[EMAIL PROTECTED] (PGP public key available.)
> Fast(!), automatic table-repair with two clicks of the mouse!
> ChimneySweep(R): "Click click, it's fixed!" {tm}
> http://www.sundialservices.com/products/chimneysweep
------------------------------
Date: Mon, 19 Mar 2001 15:41:03 -0700
From: Sundial Services <[EMAIL PROTECTED]>
Reply-To: [EMAIL PROTECTED]
Crossposted-To: comp.security.pgp.discuss,alt.security.pgp
Subject: Re: NSA in the news on CNN
Well, NSA -is- the group that brought you the National Cryptography
Museum ... which is an astounding place if you haven't been there yet.
{Actually, I can "neither confirm nor deny" if I've been there.} ;-)
>Mxsmanic wrote:
>
> CNN has a special series on the NSA (how times change!) this week, which
> may generate some interest in PGP, as I presume they'll eventually get
> around to mentioning the program. They are supposed to talk about
> encryption in days to come, but I don't know to what extent. The series
> even shows pictures from inside the NSA! Those people at Fort Meade
> must be getting desperate for funding, or something!
==================================================================
Sundial Services :: Scottsdale, AZ (USA) :: (480) 946-8259
mailto:[EMAIL PROTECTED] (PGP public key available.)
> Fast(!), automatic table-repair with two clicks of the mouse!
> ChimneySweep(R): "Click click, it's fixed!" {tm}
> http://www.sundialservices.com/products/chimneysweep
------------------------------
From: Mok-Kong Shen <[EMAIL PROTECTED]>
Subject: Re: Fast and Easy crypt send
Date: Mon, 19 Mar 2001 23:41:08 +0100
amateur wrote:
>
> I forget. Bob may use more complex function too f(k).
Note that a modern cipher like DES is such a function
and in fact a fairly complex function.
M. K. Shen
------------------------------
Date: Mon, 19 Mar 2001 15:58:33 -0700
From: Sundial Services <[EMAIL PROTECTED]>
Reply-To: [EMAIL PROTECTED]
Subject: Re: Fast and Easy crypt send
"Amateur's" scenario is overly simplistic. Any "single" secret message
is impregnable if the attacker knows nothing about it. But imagine a
more realistic scenario where thousands of messages a day must be
exchanged. The eavesdropper keeps a complete file of all of them,
unbeknownst (of course) to the parties. Furthermore, the eavesdropper
can guess the content of many of the messages.
The goal of the cryptosystem is to -assure- that the messages will be
plausibly protected from known attacks, and to -quantify- the difficulty
of breaking-in to them.
Notice that, with the published algorithms, absolutely nothing is secret
or obscure or withheld in any way .. except, the key.
>Mok-Kong Shen wrote:
>
> amateur wrote:
> >
> > I forget. Bob may use more complex function too f(k).
>
> Note that a modern cipher like DES is such a function
> and in fact a fairly complex function.
>
------------------------------
From: amateur <[EMAIL PROTECTED]>
Subject: Re: Idea
Date: Mon, 19 Mar 2001 17:59:01 -0400
I'm not using a secret algorithm.
What I'm using is not secret if ti is disclosed.
I choosen 2 categories. All users know that I used two categories.
sample :
suppose that my message before encryption is aooaaooaaaooaoaoa
If decrypt it you are going to understand that bit 0 is "a" or "o".
I Used only two letters. But I can use more letters. Sample : consonants
:prtc.... and vowels : aeiou ....
Ok.
It's a secret before encryption not after.
By using this way, I can code the bits 1 and 0 by those two categories.
And I can use random series of those two categories. So my input before
encryption will be random.
My key is random too.
So how could cryptanalysis decrypt it. No or few information in input
and no information about key.
John Joseph Trammell wrote:
>
> On Sun, 18 Mar 2001 14:00:29 -0400, amateur <[EMAIL PROTECTED]> wrote:
> > Give me a precise reference. I have the book of Menezes.
>
> Schneier, p. 2, definition of "restricted algorithm".
>
> Have you familiarized yourself with the sci.crypt.research FAQ?
>
> http://www.landfield.com/faqs/cryptography-faq/
------------------------------
From: "Joseph Ashwood" <[EMAIL PROTECTED]>
Subject: Signing/Not signing posts
Date: Mon, 19 Mar 2001 14:59:36 -0800
I am only opening a discussion on this because this seems to be an issue.
Should post's be signed?
It is my opinion that some posts should be signed, and some should not. If
something is said where it for some reason needs to be linkable to you, it
needs to be signed. For example if David Scott were to retract his
statements regarding Bruce Schneier it would require a signature of some
kind to be believed. However for the majority of posts it is unreasonable.
Consider what usefulness that signature will serve. Under most circumstances
it will serve none, and may even be detrimental. Based on this I urge people
to follow the advice to not sign posts. As always I am open to dissenting
opinions.
Joe
------------------------------
From: amateur <[EMAIL PROTECTED]>
Subject: Re: Fast and Easy crypt send
Date: Mon, 19 Mar 2001 18:01:35 -0400
If you dont have the key you have the real text which was sent.
So you have nothing!!
Sundial Services wrote:
>
> "Amateur's" scenario is overly simplistic. Any "single" secret message
> is impregnable if the attacker knows nothing about it. But imagine a
> more realistic scenario where thousands of messages a day must be
> exchanged. The eavesdropper keeps a complete file of all of them,
> unbeknownst (of course) to the parties. Furthermore, the eavesdropper
> can guess the content of many of the messages.
>
> The goal of the cryptosystem is to -assure- that the messages will be
> plausibly protected from known attacks, and to -quantify- the difficulty
> of breaking-in to them.
>
> Notice that, with the published algorithms, absolutely nothing is secret
> or obscure or withheld in any way .. except, the key.
>
> >Mok-Kong Shen wrote:
> >
> > amateur wrote:
> > >
> > > I forget. Bob may use more complex function too f(k).
> >
> > Note that a modern cipher like DES is such a function
> > and in fact a fairly complex function.
> >
------------------------------
From: amateur <[EMAIL PROTECTED]>
Subject: Re: Signing/Not signing posts
Date: Mon, 19 Mar 2001 18:06:51 -0400
??? I did not understand.
Is it real issue? signing or not?
Joseph Ashwood wrote:
>
> I am only opening a discussion on this because this seems to be an issue.
> Should post's be signed?
>
> It is my opinion that some posts should be signed, and some should not. If
> something is said where it for some reason needs to be linkable to you, it
> needs to be signed. For example if David Scott were to retract his
> statements regarding Bruce Schneier it would require a signature of some
> kind to be believed. However for the majority of posts it is unreasonable.
> Consider what usefulness that signature will serve. Under most circumstances
> it will serve none, and may even be detrimental. Based on this I urge people
> to follow the advice to not sign posts. As always I am open to dissenting
> opinions.
> Joe
------------------------------
From: Mok-Kong Shen <[EMAIL PROTECTED]>
Subject: Re: My cypher system
Date: Tue, 20 Mar 2001 00:10:25 +0100
bookburn wrote:
>
> I assume transmission between two computers, A-B, using the Internet.
> Clear text of message is composed, then a text from some common
> source is used by A for substitution, such as a page of a periodical
> available on the internet. Every space location on the page is
> numbered by computer, resulting in numbers for all the alphabet, blank
> spaces, and punctuation marks. The computer program then randomly
> selects numbers on the page that go with the letters in the message,
> resulting in a long list of single digits in binary code. This long
> list of numbers then is sent by e-mail to B, who uses the same
> computer program and common source text to translate the random
> numbers on the page back to alphabet. Spaces between words are just
> numbers indicating emplty spaces on the text page.
>
> That's basically it, just substituting numbers representing location
> on a page for the letters on that page, except that more program
> filters could be added to permute the numbers, null words could be
> woven into the product and be filtered out, etc. I assume that the
> weak point would be in identifying the text source of the
> substitution, but it seems like it would take a lot of mainframe
> computers and data bases including all the possible sources to do it.
This is akin to a book cipher, where one chooses a book,
supposedly unknown to the opponent, and sends randomly
selected locations (page, line, word number) of the words
in the book that are the same as those in the plaintext
as the ciphertext. You work on the character level instead
of on the word level and use other media than books.
The choice of the text source is indeed a crucial point.
Being, as said, a humble non-expert with rather poor
knowledge, I have to leave to the experts to eventually
comment on the security of your scheme.
M. K. Shen
------------------------------
From: amateur <[EMAIL PROTECTED]>
Subject: Re: Fast and Easy crypt send
Date: Mon, 19 Mar 2001 18:03:48 -0400
Simplictic does not mean insecure.
Sundial Services wrote:
>
> "Amateur's" scenario is overly simplistic. Any "single" secret message
> is impregnable if the attacker knows nothing about it. But imagine a
> more realistic scenario where thousands of messages a day must be
> exchanged. The eavesdropper keeps a complete file of all of them,
> unbeknownst (of course) to the parties. Furthermore, the eavesdropper
> can guess the content of many of the messages.
>
> The goal of the cryptosystem is to -assure- that the messages will be
> plausibly protected from known attacks, and to -quantify- the difficulty
> of breaking-in to them.
>
> Notice that, with the published algorithms, absolutely nothing is secret
> or obscure or withheld in any way .. except, the key.
>
> >Mok-Kong Shen wrote:
> >
> > amateur wrote:
> > >
> > > I forget. Bob may use more complex function too f(k).
> >
> > Note that a modern cipher like DES is such a function
> > and in fact a fairly complex function.
> >
------------------------------
From: Paul Rubin <[EMAIL PROTECTED]>
Subject: Re: SSL secured servers and TEMPEST
Date: 19 Mar 2001 15:15:40 -0800
Frank Gerlach <[EMAIL PROTECTED]> writes:
> > Otherwise, it's like saying you can't make a perfectly soundproof
> > room: acoustic energy will always travel through the walls and radiate
> > into the outside world, or if you surround the room completely by
> > vacuum, there still have to be some floor mountings. Does that mean
> > there's a way to eavesdrop on conversations happening in the Kremlin
> > right now, using microphones where you're sitting thousands of miles
> > away? If not, the theoretical issue is irrelevant.
>
> If they were repeating their conversations very synchronously millions of
> times, it might in fact be an interesting option to install microphones in
> the basement of your moscow embassy. Unfortunately, they will most probably
> neither repeat their conversations very often nor do that synchronously.
> Indeed, attacking a parrot is easier from a theoretical point of view than
> attacking a sane human...
The thing is, you can't install them in the embassy basement. At best
you can install them in a nearby city. Still think you can pick up
intelligible conversation?
------------------------------
From: jtnews <[EMAIL PROTECTED]>
Crossposted-To: comp.security.pgp.discuss,alt.security.pgp
Subject: Re: NSA in the news on CNN
Date: Mon, 19 Mar 2001 23:12:21 GMT
Can you email me the program time?
thanks!
Mxsmanic wrote:
>
> CNN has a special series on the NSA (how times change!) this week, which
> may generate some interest in PGP, as I presume they'll eventually get
> around to mentioning the program. They are supposed to talk about
> encryption in days to come, but I don't know to what extent. The series
> even shows pictures from inside the NSA! Those people at Fort Meade
> must be getting desperate for funding, or something!
------------------------------
From: Tim Tyler <[EMAIL PROTECTED]>
Subject: Re: One-time Pad really unbreakable?
Reply-To: [EMAIL PROTECTED]
Date: Mon, 19 Mar 2001 23:11:48 GMT
Douglas A. Gwyn <[EMAIL PROTECTED]> wrote:
: Tim Tyler wrote:
:> One is that this is a study - of Douglas A. Gwyn - under computer
:> simulation. An elaborate model of your intellect has been built, ...
: Sophomoric philosophy, and intellectually destructive.
I'm sorry you feel that way.
: For somebody who lectures scientists about the conduct of science,
: you don't appear to have made a serious study of the properties of
: knowledge, how it is obtained and validated, etc. If you had, the
: utter lack of evidence for the theory you put forth would rule it
: out of consideration.
There's no evidence /against/ it either - it is quite consistent with
all of your observations. It is quite simple - I would not like to be
told to wield Occam's rasor in this instance. When there's no evidence
either way, both options must remain possibilities - which was my point.
--
__________
|im |yler [EMAIL PROTECTED] Home page: http://alife.co.uk/tim/
------------------------------
From: Mok-Kong Shen <[EMAIL PROTECTED]>
Subject: Re: Signing/Not signing posts
Date: Tue, 20 Mar 2001 00:17:43 +0100
Joseph Ashwood wrote:
>
> I am only opening a discussion on this because this seems to be an issue.
> Should post's be signed?
>
> It is my opinion that some posts should be signed, and some should not. If
> something is said where it for some reason needs to be linkable to you, it
> needs to be signed. For example if David Scott were to retract his
> statements regarding Bruce Schneier it would require a signature of some
> kind to be believed. However for the majority of posts it is unreasonable.
> Consider what usefulness that signature will serve. Under most circumstances
> it will serve none, and may even be detrimental. Based on this I urge people
> to follow the advice to not sign posts. As always I am open to dissenting
> opinions.
I also can't see needs of signature for any posting. BTW, in
cases where a signature were necessary, one would probably
need the service of a trust centre as well.
M. K. Shen
------------------------------
From: [EMAIL PROTECTED] (Paul Schlyter)
Crossposted-To: alt.security.pgp,talk.politics.crypto
Subject: Re: OT: TV Licensing - final answer - sorry for xpost
Date: 19 Mar 2001 23:46:19 +0100
In article <99510k$l0n$[EMAIL PROTECTED]>,
Richard Herring <[EMAIL PROTECTED]> wrote:
> In article <[EMAIL PROTECTED]>, Dave Howe
>([EMAIL PROTECTED]) wrote:
>> In our last episode (<alt.security.pgp>[Sat, 17 Mar 2001 11:06:31
>> +0000]), David Hayward <[EMAIL PROTECTED]> said :
>
>>> The actual offence is "TV licence payment evasion" and is covered
>>> under the Wireless Telegraphy Act 1940 sect 1. I am fairly sure you
>>> would have to be "operating" a TV set without a licence for a
>>> prosecution to be worth while as I am led to understand that the
>>> guideline sentence is a discharge or fine for the offence. HTH
>
>> The current situation is odd though - a TV used only for a video
>> recorder to play pre-recorded movies does not require a licence, but
>> one used as a monitor for early computers that had a PAL output does -
>> Not entirely sure why.
>
> This sounds like urban mythology blurring a change of status with time.
> I think the final "does" in that sentence should be "did".
>
> In the days when people used TVs as computer monitors, there were no
> exceptions to the law for such special cases. Later it was amended
> to provide specific exemptions for using the TV as a video monitor.
Wasn't the determining factor whether the TV could receive RF
signals? I.e. if you had a monitor with baseband input only, no
license was needed, but if the monitor also included a tuner so you
could actually receive TV transmissions, then a license was needed.
Liwewise, a license would be needed for a VCR if the VCR had an
integral tuner (as most VCR's do).
--
================================================================
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: [EMAIL PROTECTED] (Paul Schlyter)
Subject: Re: [OT] Why Nazis are evil
Date: 19 Mar 2001 23:47:11 +0100
[EMAIL PROTECTED] (Benjamin Goldberg) wrote in
<[EMAIL PROTECTED]>:
>Paul Schlyter wrote:
>>
>> In article <[EMAIL PROTECTED]>,
>> Benjamin Goldberg <[EMAIL PROTECTED]> wrote:
>>
>>> The problem with bringing up Nazis, is that *they* didn't believe
>>> that what they did was unethical or immoral. In fact, if you were
>>> to accept one single premise -- that anyone who isn't a male aryan
>>> isn't a person -- you would consider everything they did to be
>>> perfectly reasonable. Further, and possibly more importantly wrt
>>> your argument, the way they acted towards those who they *did*
>>> consider persons, was as moral and as ethical as you or I would act
>>> towards each other. The only thing that made them evil was their
>>> perception and treatment of non-aryans as non-persons.
>>
>> So you're claiming that it's perfectly OK to torture a creature as
>> long as it's not a human?
>
> Torturing animals makes people less emotionally disinclined to hurt
> humans, therefor it's wrong to torture animals.
Only because of that, and not at all because of the suffering of the
animals?
> But ignoring the emotional changes it produces... if you had mice in
> your house, would you have any qualms about getting rid of them? Even
> if the only traps you had were the wood-wire-spring ones, which
> sometimes don't kill, but might result in a lingering death for the
> rodent?
What prevents you from buying better mouse traps? The mouse might
even escape that wood-wire-spring trap, and then you didn't get
rid of it....
I occasionally have mice in my country house (they sneak in when it's
cold outside), and I am trying to get rid of them. And I have mouse
traps which are better than those wood-wire-spring ones.
> Also, how do you feel about testing makeup on animals?
That's making animals suffer just because of the pleasure of humans,
so it's really equivalent to torture. I wonder how many girls would
buy makeup if they had to test it on the animals themselves....
--
================================================================
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: "Joseph Ashwood" <[EMAIL PROTECTED]>
Subject: Re: How to eliminate redondancy?
Date: Mon, 19 Mar 2001 15:28:59 -0800
SCOTT19U.ZIP_GUY" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]...
Actually I can prove that your compression is not 1-1 onto, based on one
simple assumption, it compresses. Given a set consisting of each possible
input up to a given length, the best you can manage is a permutation. The
average length will be the same after as before. My statements really did
not specify strictly compression, but allowed for the use of a padding
transform (or the proper type) and/or and AONT. It seems reasonable to state
that your rather winded explaination of "1-1 compression" could in fact be a
1-1 onto transform, however stating it as such would be much more
recognisable than
> But I also asked what compression you used before you encrypt something.
> take h2com.exe it map every member of 8-bit binary files to
> a one and only one member of the same set. The reverse maps
> every member back.
> For any file X then Uncompress( Compress ( X)) = X
> and also for any file Y then Compress( Uncompress (Y)) = Y
> does this not meet your defination.
Of course the first also requires that the reader have some minor amount of
Computer Science, Function Theory, etc knowledge. Personally I think this
was introduced 3rd semester Computer Science, bachelor's degreee.
> Does the compression you use
> meet this criteria.
Actually I don't tend to use compression out of a preference for other types
of transforms, and the realisation that quite often the length of the
encrypted information reveals much of the content.
Joe
------------------------------
From: [EMAIL PROTECTED] (Steve Meyer)
Subject: Re: Is SHA-1 Broken?
Reply-To: [EMAIL PROTECTED]
Date: 19 Mar 2001 23:54:30 GMT
On Mon, 19 Mar 2001 17:19:39 -0500, Jim Steuert <[EMAIL PROTECTED]> wrote:
>No, you didn't miss anything. I did. I jumped to conclusions.
>
<snip>
>
>Do you know of any research using BDD's to invert cipher or
>hash functions? I am off to learning more about BDDs.
There has been quite a large amount of experiene with BDDs in electronic
design. BDD have a serious problem is determining the value computed by
a combinatorial electronic circuit. Namely, size of BDD's can and
does grow exponentially with the number of inputs. In electronic
design, designers learn to design in such a way as to minimize this
exponential explosion. But converting a encryption algorithm into
a BDD may be an interesting test for quality of encryption algorithm.
/Steve
>
>Thanks for pointing out the flaw in my alarmist posting.
>
>
>David Wagner wrote:
>
>> Jim Steuert wrote:
>> >Is SHA-1 Broken? In a recent thesis by Richard Drews Dean, he supplies
>> >initial values for SHA-1's A,B,C,D,and E for which the input block "abc"
>> >(in ascii, padded and Merkle-Damgard strenghtened), is a fixed point.
>>
<snip>
--
Steve Meyer Phone: (415) 296-7017
Pragmatic C Software Corp. Fax: (415) 296-0946
220 Montgomery St., Suite 925 email: [EMAIL PROTECTED]
San Francisco, CA 94104
------------------------------
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