Cryptography-Digest Digest #849, Volume #9 Thu, 8 Jul 99 11:13:03 EDT
Contents:
Re: Summary of 2 threads on legal ways of exporting strong crypto (Mok-Kong Shen)
Re: Is Stenography legal? (Mok-Kong Shen)
Re: Is Stenography legal? ([EMAIL PROTECTED])
Re: optimizations (for feedback PRNGs...) ([EMAIL PROTECTED])
Re: optimizations (for feedback PRNGs...) ([EMAIL PROTECTED])
Re: optimizations (for feedback PRNGs...) ([EMAIL PROTECTED])
Re: Standard Hash usage (Keith A Monahan)
Re: Is Stenography legal? (Mok-Kong Shen)
Re: Can Anyone Help Me Crack A Simple Code? (Coen Visser)
Re: Is Stenography legal? (Robert G. Durnal)
Re: Is Stenography legal? (Patrick Juola)
Re: Standard Hash usage ([EMAIL PROTECTED])
Re: Weakness of MLCG style encryption ([EMAIL PROTECTED])
Re: Is Stenography legal? ([EMAIL PROTECTED])
somewhat optimization works... (PRNG code) ([EMAIL PROTECTED])
Re: Properties of Chain Addition? (John Savard)
Re: Properties of Chain Addition? (John Savard)
Re: Is Stenography legal? (Mok-Kong Shen)
Re: Impossible to decrypt files encrypted with attached program - encrypt.exe [0/1]
(John Savard)
Netiquette Question (John Savard)
----------------------------------------------------------------------------
From: Mok-Kong Shen <[EMAIL PROTECTED]>
Crossposted-To: talk.politics.crypto
Subject: Re: Summary of 2 threads on legal ways of exporting strong crypto
Date: Thu, 08 Jul 1999 14:35:28 +0200
Douglas A. Gwyn wrote:
> It's not very hard to convert, say, C source code to a *correct*
> English procedural description. But, as perhaps with Scott19u,
> the *meaning* and *reason* behind the source code may not be
> evident, even to a human skilled in the programming language.
I am assuming the favourable case that the author himself converts.
That's not hard (difficult) but inconvenient. It is however very
hard to construct a software that can convert an ARBITRARY program
to a faithful (human utilizable) description and back. On the
other hand, I should perhaps constrain my original statement a bit:
By (suitablely) restricting the class of programs to be converted,
i.e. not ARBITRARY programs, the task appears to be feasible with
current technology.
>
> However, this seems to have little to do with the realities of
> crypto export control. The simple fact is, the US Executive
> keeps imposing rules of their own devising, and the people let
> them get away with it. So no matter what you do to try to
> export something the Administration doesn't want exported, it
> might be blocked by arbitrary fiat for which there is no
> effective appeal.
The bureaucrats of other countries are not behaving better within
the (often huge) realm of their power. Anyway the Bernstein case is
significant in this large context, I believe.
M. K. Shen
------------------------------
From: Mok-Kong Shen <[EMAIL PROTECTED]>
Subject: Re: Is Stenography legal?
Date: Thu, 08 Jul 1999 11:46:31 +0200
[EMAIL PROTECTED] wrote:
>
> Is stenography legal? I mean what if I took a 100 byte message and
> spread out the plaintext among 1024 bytes of random giblygook. It
> would be hard to decrypt (how so is challenging)....
>
> Is this against EAR?
Steganography is in my humble opinion a form of encryption and
belongs to cryptology, in fact it was one of the oldest methods
for achieving information security, even though there are certainly
persons who disagree on that.
Thus application of steganographc techniques is legal exactly where
encryption is legal.
M. K. Shen
------------------------------
From: [EMAIL PROTECTED]
Subject: Re: Is Stenography legal?
Date: Thu, 08 Jul 1999 13:10:07 GMT
In article <[EMAIL PROTECTED]>,
Mok-Kong Shen <[EMAIL PROTECTED]> wrote:
> Steganography is in my humble opinion a form of encryption and
> belongs to cryptology, in fact it was one of the oldest methods
> for achieving information security, even though there are certainly
> persons who disagree on that.
>
> Thus application of steganographc techniques is legal exactly where
> encryption is legal.
But stenagraphy is not listed as encryption. So is it against EAR? :)
In fact one might link RSA padding with stenagraphy ...
Tom
--
PGP key is at:
'http://mypage.goplay.com/tomstdenis/key.pgp'.
Free PRNG C++ lib:
'http://mypage.goplay.com/tomstdenis/prng.html'.
Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't.
------------------------------
From: [EMAIL PROTECTED]
Subject: Re: optimizations (for feedback PRNGs...)
Date: Thu, 08 Jul 1999 13:12:11 GMT
In article <[EMAIL PROTECTED]>,
[EMAIL PROTECTED] (S.T.L.) wrote:
> <<To the best of my knowledge the code has to work>>
>
> So, could one export PGP code missing a crucial "A=0" (in relevant C
speak, of
> course) somewhere?
Probably. If the source doesn't work it's not an encryption tool is
it? It's just bad code :)
Tom
--
PGP key is at:
'http://mypage.goplay.com/tomstdenis/key.pgp'.
Free PRNG C++ lib:
'http://mypage.goplay.com/tomstdenis/prng.html'.
Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't.
------------------------------
From: [EMAIL PROTECTED]
Subject: Re: optimizations (for feedback PRNGs...)
Date: Thu, 08 Jul 1999 13:16:42 GMT
In article <[EMAIL PROTECTED]>,
Terje Mathisen <[EMAIL PROTECTED]> wrote:
> mov ebx,[x] ; Get X index
> mov ecx,[y] ; Get Y index
>
> ; A one-cycle AGI stall here unless you can leave X and
> ; Y in registers all the time!
>
> mov eax,[ebx] ; Get state[x]
> mov edx,[ecx] ; and state[y]
>
> add eax,edx ; Add
> mov ecx,nextIndex[ecx*4]
>
> mov [ebx],eax
> mov ebx,nextIndex[ebx*4]
>
> mov [y],edx
> mov [x],ebx
>
> which is ten perfectly paired instructions, using a total of 6 cycles.
Can this be looped or unrolled (i.e to fill an arbitrary buffer)?
> A good compiler should be able to generate something very close to
that:
>
> sx = state[x];
> sy = state[y];
>
> sx += sy;
> y = nextIndex[y];
>
> state[x] = sx;
> x = nextIndex[x];
>
> return sx;
>
Why not just use
return state[nextindext[++x]] += state[nextindex[++y]];
For the 55, 24, 0 PRNG x and y would start at (17, 53) to keep the
state design. The compiler would have the benefit of keeping lots in
the accumulator. This code is also more compact...
Thanks for the feedback, seems some people are better at asm then me :)
Tom
--
PGP key is at:
'http://mypage.goplay.com/tomstdenis/key.pgp'.
Free PRNG C++ lib:
'http://mypage.goplay.com/tomstdenis/prng.html'.
Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't.
------------------------------
From: [EMAIL PROTECTED]
Subject: Re: optimizations (for feedback PRNGs...)
Date: Thu, 08 Jul 1999 13:22:09 GMT
In article <7m28bf$apg$[EMAIL PROTECTED]>,
[EMAIL PROTECTED] wrote:
> return state[nextindext[++x]] += state[nextindex[++y]];
Doh. That should read
return state[x = ni[++x]] += state[y = ni[++y]];
Unless you have a huge buffer :). I guess I hit send to quickly.
Tom
--
PGP key is at:
'http://mypage.goplay.com/tomstdenis/key.pgp'.
Free PRNG C++ lib:
'http://mypage.goplay.com/tomstdenis/prng.html'.
Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't.
------------------------------
From: [EMAIL PROTECTED] (Keith A Monahan)
Subject: Re: Standard Hash usage
Date: 8 Jul 1999 12:59:11 GMT
Tom,
[EMAIL PROTECTED] wrote:
: I will stick with my previous suggestion. do this
: H1 = SHA-1(M)
: H2 = SHA-1(M||H1)
: This is kinda a standard for making larger hashes. It is also
: documented in a paper about 'key stretching' by Bruce Schneier. (only
: hwe used a private key and salt...)
Well remember my objective - I'm attempting to write a brute force
cracker that will work with a particular program - so I'm stuck to using
whatever it is they used. More research should turn that up, I hope.
: I think Jim Golligy (sorry I forgot the spelling) has a good copy of
: SHA-1. Ask around in this group I know I saw a Good copy...
Hrrrmm.. Anyone? :)
: You could always read FIPS-180 and implement it yourself? MD5 (RFC
: 1321 I think...) has C source code included. I have a copy of MD5 (the
: RFC) if you want I could email it in private...
Yeah, I have both Schneier's book and another book that details SHA-1.
The implementation from reading the book looks fairly straightforward -- but
all the implementations I've seen are bloated. You know, pardon my French, but
fuck modularity. Why people find it necessary to spread 3k of code across
17 files is beyond me.
: Tom
Keith
------------------------------
From: Mok-Kong Shen <[EMAIL PROTECTED]>
Subject: Re: Is Stenography legal?
Date: Thu, 08 Jul 1999 15:34:01 +0200
[EMAIL PROTECTED] wrote:
>
> > Thus application of steganographc techniques is legal exactly where
> > encryption is legal.
>
> But stenagraphy is not listed as encryption. So is it against EAR? :)
> In fact one might link RSA padding with stenagraphy ...
I was arguing on grounds of principles. If a certain crypto law lists
certain specific algorithms as forbidden or restricted and there are
no steganographic techniques listed there, then it seems sensible to
assume that steganography is free. Even in the case steganography for
secrect message transmissions is forbidden, it is conceivable
that the techniques in general may be allowed for other usages,
e.g. in watermarking. Being ignorant of the text of EAR, I am unable
to say anything relating to that.
M. K. Shen
------------------------------
From: [EMAIL PROTECTED] (Coen Visser)
Subject: Re: Can Anyone Help Me Crack A Simple Code?
Date: 8 Jul 1999 13:51:07 GMT
S.T.L. <[EMAIL PROTECTED]> wrote:
> <<The human eye can distinguish around 100,000 colors of visible light.>>
> I've actually heard figures of a few million, but less than 16 million
> and more than 100,000. (It was in connection with someone saying how
> 24bit color monitors are already overkill, and 32bit color is insane.)
Good (computer) monitors can only produce about half the spectrum that
the human eye can see. But for practical purposes the human eye can
distinguish about 40000 colors and about 50 levels of grey *at the same time*.
32 bits color schemes are mostly used to define opaqueness of colors so you can
define overlays in a convenient way. So 16 million colors is not overkill
as long as you don't display them at the same time.
Regards,
Coen Visser
------------------------------
From: [EMAIL PROTECTED] (Robert G. Durnal)
Subject: Re: Is Stenography legal?
Date: 8 Jul 1999 14:08:10 GMT
In <7m163f$vsn$[EMAIL PROTECTED]>, [EMAIL PROTECTED] wrote:
: Is stenography legal? I mean what if I took a 100 byte message and
: spread out the plaintext among 1024 bytes of random giblygook. It
: would be hard to decrypt (how so is challenging)....
: Is this against EAR?
: Tom
First, I think you mean STEGANOGRAPHY, not STENOGRAPHY. But it is
legal, and not against EAR. In fact, EAR does NOT apply to sending of coded
messages, but only to the dissemination of encryption software itself. And
steganography is not encryption.
For a simple steganography program, look for the PGE20 program
at www.afn.org/~afn21533/pge20.zip. Its predecessor, PGE (not written by
myself) was not exportable because it contained a simple encryption routine
with 64-bit strength. But PGE20 omits the encryption and is perfectly legal
to export.
=========
My home page URL=http://members.tripod.com/~afn21533/ Robert G. Durnal
Hosting HIDE4PGP, HIDESEEK v5.0, PGE, TinyIdea (link) [EMAIL PROTECTED]
and BLOWFISH in both Windows and mini-DOS versions. [EMAIL PROTECTED]
EAR may apply, so look for instructions.
------------------------------
From: [EMAIL PROTECTED] (Patrick Juola)
Subject: Re: Is Stenography legal?
Date: 8 Jul 1999 10:05:35 -0400
In article <[EMAIL PROTECTED]>,
Mok-Kong Shen <[EMAIL PROTECTED]> wrote:
>[EMAIL PROTECTED] wrote:
>>
>
>> > Thus application of steganographc techniques is legal exactly where
>> > encryption is legal.
>>
>> But stenagraphy is not listed as encryption. So is it against EAR? :)
>> In fact one might link RSA padding with stenagraphy ...
>
>I was arguing on grounds of principles. If a certain crypto law lists
>certain specific algorithms as forbidden or restricted and there are
>no steganographic techniques listed there, then it seems sensible to
>assume that steganography is free.
I do not believe that it is the case that "a certain crypto law
lists certain specific algorithms as forbidden"; the regs require
individual approval for use/export.
-kitten
------------------------------
From: [EMAIL PROTECTED]
Subject: Re: Standard Hash usage
Date: Thu, 08 Jul 1999 13:59:42 GMT
In article <7m27av$gio$[EMAIL PROTECTED]>,
[EMAIL PROTECTED] (Keith A Monahan) wrote:
> Well remember my objective - I'm attempting to write a brute force
> cracker that will work with a particular program - so I'm stuck to
using
> whatever it is they used. More research should turn that up, I hope.
>
Ah objective. Ok.
> Yeah, I have both Schneier's book and another book that details SHA-1.
> The implementation from reading the book looks fairly
straightforward -- but
> all the implementations I've seen are bloated. You know, pardon my
French, but
> fuck modularity. Why people find it necessary to spread 3k of code
across
> 17 files is beyond me.
Cuz they never wrote programs for MCUs with 4K of code space and 256
bytes of ram...(in ASM is fun, in C is even trickier :) )
I know this is OT, but why is Windows with all it's DLL glory still
pack 84MB .EXE programs? (I.e these people should not get involved
with cryptography cuz they will kill it!)
Tom
--
PGP key is at:
'http://mypage.goplay.com/tomstdenis/key.pgp'.
Free PRNG C++ lib:
'http://mypage.goplay.com/tomstdenis/prng.html'.
Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't.
------------------------------
From: [EMAIL PROTECTED]
Crossposted-To: sci.math
Subject: Re: Weakness of MLCG style encryption
Date: Thu, 08 Jul 1999 13:19:12 GMT
In article <[EMAIL PROTECTED]>,
[EMAIL PROTECTED] (Terry Ritter) wrote:
> Hmmm....
>
> 1. Retter, C. 1984. Cryptanalysis of a MacLaren-Marsaglia System.
> Cryptologia. 8(2): 97-108.
>
> 2. Retter, C. 1985. A Key-Search Attack on MacLaren-Marsaglia
> Systems. Cryptologia. 9(2): 114-130.
>
> 3. Letters to the Editor. 1984. Cryptologia. 8(4): 374-378.
I take it that refers to Algorithm M? Do you have online copies of the
papers?
Tom
--
PGP key is at:
'http://mypage.goplay.com/tomstdenis/key.pgp'.
Free PRNG C++ lib:
'http://mypage.goplay.com/tomstdenis/prng.html'.
Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't.
------------------------------
From: [EMAIL PROTECTED]
Subject: Re: Is Stenography legal?
Date: Thu, 08 Jul 1999 14:09:43 GMT
In article <7m27e2$cun$[EMAIL PROTECTED]>,
[EMAIL PROTECTED] (Patrick Juola) wrote:
> In article <7m163f$vsn$[EMAIL PROTECTED]>, <[EMAIL PROTECTED]>
wrote:
> >Is stenography legal? I mean what if I took a 100 byte message and
> >spread out the plaintext among 1024 bytes of random giblygook. It
> >would be hard to decrypt (how so is challenging)....
>
> Isn't the work "steganography"? "Stenography" is something my
> secretary used to do back when we had personal secretaries and they
> took dictation.
Hmm slight diff... :)
> And the answer depends strongly on the random 100 byte message.
> Applying steganography will not of itself make an illegal transmission
> legal -- but nor will it make a legal transmission illegal.
You must be a lawyer... (no offense)
>
> >Is this against EAR?
>
> Only if you're hiding cryptographic munitions. If you're hiding a
> recipe for egg salad, there's no problem.
What if the egg salad was toxic?
Tom
--
PGP key is at:
'http://mypage.goplay.com/tomstdenis/key.pgp'.
Free PRNG C++ lib:
'http://mypage.goplay.com/tomstdenis/prng.html'.
Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't.
------------------------------
From: [EMAIL PROTECTED]
Subject: somewhat optimization works... (PRNG code)
Date: Thu, 08 Jul 1999 13:48:37 GMT
Could someone please take a peak at my C++ file (arng.cpp) that I have
posted on my website. I optimized the additive rngs to use a simpler
index (which was suggested by another sci.cryptster). Basically the
rngs work like this
return state[x = ni[++x]] += state[y = ni[++y]];
To keep the state design I subtracted one from all the initialization
values of x and y.
Could some please check to make sure that it still works the same
(basically proof read the code). They are minor changes (but it's
normally the minor stuff that becomes major.)
Thanks,
Tom
--
PGP key is at:
'http://mypage.goplay.com/tomstdenis/key.pgp'.
Free PRNG C++ lib:
'http://mypage.goplay.com/tomstdenis/prng.html'.
Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't.
------------------------------
From: [EMAIL PROTECTED] (John Savard)
Crossposted-To: sci.math
Subject: Re: Properties of Chain Addition?
Date: Thu, 08 Jul 1999 14:57:56 GMT
[EMAIL PROTECTED] (John Savard) wrote, in part:
>which prompts me to ask...
>is it known that polynomials of the form x^n + x + 1 are likely to
>give rise to shift registers with reasonably long periods even if not
>maximal ones?
Oops, that should have been x^n + x^(n-1) + 1, although it is
equivalent thanks to the reversal property. I fell into a typo in a
popular book about cryptography.
On my web site, at
http://members.xoom.com/quadibloc/co041101.htm
the page now has added, at the beginning, a bit more information on
the properties of shift registers, and the proper direction in which
to assign the terms of the characteristic polynomial to the cells of a
shift register is illustrated - with an explanation of why it has to
be that way.
John Savard ( teneerf<- )
http://members.xoom.com/quadibloc/crypto.htm
------------------------------
From: [EMAIL PROTECTED] (John Savard)
Crossposted-To: sci.math
Subject: Re: Properties of Chain Addition?
Date: Thu, 08 Jul 1999 15:02:48 GMT
[EMAIL PROTECTED] (John Savard) wrote, in part:
>The VIC cipher used by Russian spies involved a technique for
>generating pseudorandom numbers known as "chain addition".
An E-mail I recieved in response to this post noted one condition
where chain addition will result in a less-than-maximal period:
whenever the modulus of the shift register cells is not prime, if all
their contents share a common factor with this modulus (i.e., if its a
base 10 shift register, if all the starting numbers are even, or if
they're all either 0 or 5) then all subsequent digits generated will
also be divisible by that number, limiting the number of states.
John Savard ( teneerf<- )
http://members.xoom.com/quadibloc/crypto.htm
------------------------------
From: Mok-Kong Shen <[EMAIL PROTECTED]>
Subject: Re: Is Stenography legal?
Date: Thu, 08 Jul 1999 17:02:31 +0200
Patrick Juola wrote:
>
> I do not believe that it is the case that "a certain crypto law
> lists certain specific algorithms as forbidden"; the regs require
> individual approval for use/export.
In such a case the power of the bureaucrats is virtually infinite.
The approval could depend e.g. on the applicant's personal
characteristics.
M. K. Shen
------------------------------
From: [EMAIL PROTECTED] (John Savard)
Subject: Re: Impossible to decrypt files encrypted with attached program - encrypt.exe
[0/1]
Date: Thu, 08 Jul 1999 14:59:15 GMT
[EMAIL PROTECTED] (Bob) wrote, in part:
>Can anyone decrypt files encrypted with the attached program?
I saw this binary in alt.sources.crypto, and binaries don't belong
there any more than they do here.
Anyhow, few people are inclined to load just any executable someone
suggests they try from the Internet on their machines, for good
reason.
John Savard ( teneerf<- )
http://members.xoom.com/quadibloc/crypto.htm
------------------------------
From: [EMAIL PROTECTED] (John Savard)
Subject: Netiquette Question
Date: Thu, 08 Jul 1999 15:06:46 GMT
In general, if I recieve a message by E-mail containing information
related to a posting that I feel is relevant enough to deserve being
preserved in a thread,
I post the information,
but I respect the E-mail sender's privacy by not identifying who sent
the E-mail, while still acknowledging that the source of the
information was an E-mail, and not me.
Although I believe that is a reasonable procedure, unless it is
specifically noted in the E-mail that the information is confidential
for whatever reason, perhaps a more cautious procedure is expected?
John Savard ( teneerf<- )
http://members.xoom.com/quadibloc/crypto.htm
------------------------------
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