Cryptography-Digest Digest #943, Volume #12 Tue, 17 Oct 00 09:13:01 EDT
Contents:
Re: useful literature? (NorasToy)
Re: Counting one bits is used how? (Rob Warnock)
Smartcard, Mathematical Proof? (Mykhailo Lyubich)
Re: Basic skills and equipment... (Tom St Denis)
Re: Basic skills and equipment... ("Sam Simpson")
Re: Counting one bits is used how? (Mok-Kong Shen)
Re: Simple Intro Encryption Info Wanted (John Savard)
Re: Crypto technology recommendations? (Wei Dai)
Re: Basic skills and equipment... (Bob Silverman)
Re: Rijndael implementations (Tim Tyler)
Re: Rijndael implementations (Tim Tyler)
Re: Basic skills and equipment... (Tom St Denis)
Re: Crypto technology recommendations? (Tom St Denis)
Re: Smartcard, Mathematical Proof? (Tom St Denis)
Re: A new paper claiming P=NP (Dima Pasechnik)
Re: Works the md5 hash also for large datafiles (4GB) ? (Daniel Leonard)
Re: Works the md5 hash also for large datafiles (4GB) ? (Tom St Denis)
Re: gender vs. sex [was Rijndael implementations] (Richard Heathfield)
----------------------------------------------------------------------------
Date: Tue, 17 Oct 2000 12:10:24 +0200
From: NorasToy <[EMAIL PROTECTED]>
Subject: Re: useful literature?
Florian Peterl wrote:
> has anybody any recommendation concerning literature in cryptography?
Well the standard lecture for cryptography is always 'Applied
Cryptography' by Bruce Schneier.
------------------------------
From: [EMAIL PROTECTED] (Rob Warnock)
Subject: Re: Counting one bits is used how?
Date: 17 Oct 2000 10:30:04 GMT
David Wagner <[EMAIL PROTECTED]> wrote:
+---------------
| 1. Calculating the dot-product x.y can be computed in three instructions
| as popcount(x^y)&1
+---------------
I think you probably meant "popcount(x&y)&1", since the "product" in
dot-product needs an AND, not an XOR.
+---------------
| Dot-products are used all over the place in GF(2) math: e.g., in LFSR's.
+---------------
Well, yes, dot-products are used sometimes in GF math, but LFSRs are more
likely to use N-way parity, that is, "popcount(x)&1", in the feedback terms.
+---------------
| 2. Calculating the Hamming distance between two GF(2)-vectors x,y can be
| done in two instructions as popcount(x^y) if x,y are represented as
| machine words.
+---------------
Yup.
-Rob
=====
Rob Warnock, 31-2-510 [EMAIL PROTECTED]
Network Engineering http://reality.sgi.com/rpw3/
Silicon Graphics, Inc. Phone: 650-933-1673
1600 Amphitheatre Pkwy. PP-ASEL-IA
Mountain View, CA 94043
------------------------------
From: Mykhailo Lyubich <[EMAIL PROTECTED]>
Subject: Smartcard, Mathematical Proof?
Date: Tue, 17 Oct 2000 12:37:24 +0200
Reply-To: [EMAIL PROTECTED]
Hi
does somebody know the mathematical proof for
whether a system with the smartcard is better
protected than an equivalent system without
the smartcard. I appreciate any comments and examples
with formal proof for such systems.
With best regards.
--
Mykhailo Lyubich
Dept.of Computer Science office phone +49-381-4983407
University of Rostock office fax +49-381-4983440
Albert Einstein Strasse 21
http://wwwtec.informatik.uni-rostock.de/~ljubich/
D-18051 Rostock, Germany mailto:[EMAIL PROTECTED]
------------------------------
From: Tom St Denis <[EMAIL PROTECTED]>
Subject: Re: Basic skills and equipment...
Date: Tue, 17 Oct 2000 10:27:21 GMT
In article <8sghe6$1iq$[EMAIL PROTECTED]>,
[EMAIL PROTECTED] (Scott Craver) wrote:
> Tom St Denis <[EMAIL PROTECTED]> wrote:
> >Bob Silverman <[EMAIL PROTECTED]> wrote:
> >>
> >> You are STILL EVADING the question that was ASKED. The poster
asked a
> >> very specific question. He didn't ask "how can I get an elementary
> >> intro to crypto?" He did ask "what math background is required?"
> >
> >Then you should have told the poster to use sci.math or alt.math
> >instead. His post is irrevelant and off topic.
>
> Asking what math background is relevant to crypto is
> off topic for sci.crypt??!!
>
> Of course, his question was perfectly on-topic, and without
> your retorts the rest of the thread would be on-topic too.
Ok obviously you guys are just waiting to flame me at every chance. I
think if you want to get into crypto-math you should know very basic
terms like "ciphertext" or "salt". Otherwise what's the point?
Of course this concept of actually knowing what you're talking about
eludes most of you here (and me sometimes).
> >> Further, learning the crypto is EASY with the right math
background.
> >> Learning it without the background is very HARD.
> >
> >No, it isn't. I know some people with strong math+computer science
> >background that don't have a clue about cryptography (despite
recently
> >forming a company to market crypto solutions).
>
> Your second sentence does not imply your first sentence.
> For a number of reasons.
>
> Seriously, learning crypto without a math background is
> hard. Without it, the best you can do is go on facts
> already published in Applied Cryptography (use these
> polynomials, here's source code for RSA, et cetera.)
>
> If by "learning crypto" you mean learning enough to talk
> about it or implement existing algorithms, fine. If
> by "learning crypto" you mean being able to design or
> analyze systems, sorry, but you need lots and lots of math.
Either way you still need to know crypto vocabulary. So I don't see
where Bob get's off telling me my "read the faq, some good intros,
etc..." is off-course.
Tom
Sent via Deja.com http://www.deja.com/
Before you buy.
------------------------------
From: "Sam Simpson" <[EMAIL PROTECTED]>
Subject: Re: Basic skills and equipment...
Date: Tue, 17 Oct 2000 12:23:15 +0100
Tom St Denis <[EMAIL PROTECTED]> wrote in message
news:8sh9i6$9j6$[EMAIL PROTECTED]...
<SNIP>
> Ok obviously you guys are just waiting to flame me at every chance.
I
> think if you want to get into crypto-math you should know very
basic
> terms like "ciphertext" or "salt". Otherwise what's the point?
<SNIP>
Tom, you're the most prolific poster in this forum and you sometimes
shoot from the hip - are you really surprised that some people will
disagree with you on occasion? I think you could quite correctly
call Bobs comments "a flame", but he has problems being civil to most
people here, so don't take personal offense.
Rgds,
--
Sam Simpson
http://www.scramdisk.clara.net/ for ScramDisk hard-drive encryption &
Delphi Crypto Components. PGP Keys available at the same site.
------------------------------
From: Mok-Kong Shen <[EMAIL PROTECTED]>
Subject: Re: Counting one bits is used how?
Date: Tue, 17 Oct 2000 13:49:36 +0200
Peter van der Linden wrote:
>
> How does counting the number of 1 bits in a word
> relate to crypto?
>
> Just curious about why this seemingly recondite instruction
> pops up in various instruction sets. How is it useful?
One potential application I suppose is that the LSB of the
count gives the parity which could be of some use in
randomness. In information retrieval the different bits may
signify e.g. the fulfillment of certain criteria and the
count may become a convenient measure.
M. K. Shen
============================
http://home.t-online.de/home/mok-kong.shen
------------------------------
From: [EMAIL PROTECTED] (John Savard)
Subject: Re: Simple Intro Encryption Info Wanted
Date: Tue, 17 Oct 2000 11:28:12 GMT
On Tue, 17 Oct 2000 03:29:56 -0000, Chris Frost <[EMAIL PROTECTED]>
wrote, in part:
>C2d73bAB11c9CA6
>
>42175484c2bB 1CF6b359C
>
>Without any other info. I'd guess they are indead human-targeted algorthiums
>(or at least they use only letters and numbers and not all of ascii or binary,
>etc).
Since the letters are all from A to F, it is possible - unless the
case of the letters is significant, and the form is a trick - that
those are hexadecimal digits, in which case the message is
'machine-targeted' but expressed in the human-readable hexadecimal
form.
So you would have
C2 D7 3B AB 11 C9 CA 64 21 75 48 4C 2B B1 CF 6B 35 9C
as bytes, if the breaking of the digits into groups is not
significant. (If it is, some of the groups have an odd number of
digits in them.)
Since (either way) there are groups larger than 80 hex, the message
isn't just in plain ASCII.
John Savard
http://home.ecn.ab.ca/~jsavard/crypto.htm
------------------------------
From: Wei Dai <[EMAIL PROTECTED]>
Subject: Re: Crypto technology recommendations?
Date: Tue, 17 Oct 2000 04:46:57 -0700
In article <8s9jkg$g20$[EMAIL PROTECTED]>, [EMAIL PROTECTED] says...
> Why? His C++ kit will not compile with DJGPP. Seems rather half-assed
> to me since it hasn't worked with DJGPP for other two years. As far as
> I know DJGPP is (like GCC) a "standard" compliant compiler. So it's
> his code that makes use of some compiler specific thingy...
Actually Crypto++ 3.2 compiles just fine with DJGPP 2.03. There is a
linker issue, which you can work around by using the makefile at
weidai.com/djgpp-Makefile. (It turns on DJGPP's support for weak
symbols.)
--
cryptopp.com - a free C++ class library of cryptographic schemes
------------------------------
From: Bob Silverman <[EMAIL PROTECTED]>
Subject: Re: Basic skills and equipment...
Date: Tue, 17 Oct 2000 11:43:56 GMT
In article <8sghrf$1mc$[EMAIL PROTECTED]>,
[EMAIL PROTECTED] (Scott Craver) wrote:
> Alexandros Andreou <[EMAIL PROTECTED]> wrote:
<snip>
Hi,
>
> What level of mathematics are you interested in? College
> level, graduate level? I wouldn't want to recommend
> Hungerford's _Algebra_ to a high school student (or even to
> an interested non-mathematician; it's a dry read.)
> Hey Bob? AYT? What would you recommend as a book on
> abstract algebra to a young'un?
Cerainly not Hungerford or Lang. I think well of Birkhoff/MacLane.
VanDerWaerden is a good book if you can find a translation.
A good book from a comp. sci. perspective is "Modern Applied Algebra"
by Birkhoff & Bartee.
(I got to take algebra from Birkhoff; it was one of the best courses
I ever had)
--
Bob Silverman
"You can lead a horse's ass to knowledge, but you can't make him think"
Sent via Deja.com http://www.deja.com/
Before you buy.
------------------------------
From: Tim Tyler <[EMAIL PROTECTED]>
Subject: Re: Rijndael implementations
Reply-To: [EMAIL PROTECTED]
Date: Tue, 17 Oct 2000 11:33:18 GMT
Benjamin Goldberg <[EMAIL PROTECTED]> wrote:
: Tim Tyler wrote:
:> Paul Schlyter <[EMAIL PROTECTED]> wrote:
:> :Java is also designed to to execute on only one single architecture,
:> :the Java virtual machine, while C was designed to execute on many
:> :different architectures.
:>
:> There's no difference between C and Java in this respect. Java was
:> designed (from the first white paper) to be compiled to whatever
:> processing hardware is available. The difference from C in this
:> respect is that C is often shipped in compiled form, while Java is
:> almost always compiled on the target machine at some stage before
:> being executed.
: Untrue, UNLESS you are considering just-in-time compiling to be
: compiling.
Well, naturally I am consideriung "just-in-time compiling" to be
compiling.
See the "compiling" there in the name? It is there with good reason.
--
__________ http://alife.co.uk/ http://mandala.co.uk/
|im |yler [EMAIL PROTECTED] http://hex.org.uk/ http://atoms.org.uk/
------------------------------
From: Tim Tyler <[EMAIL PROTECTED]>
Subject: Re: Rijndael implementations
Reply-To: [EMAIL PROTECTED]
Date: Tue, 17 Oct 2000 11:58:50 GMT
Daniel James <[EMAIL PROTECTED]> wrote:
: In article <[EMAIL PROTECTED]>, Tim Tyler wrote:
[what do you propose to call what /I/ still call a byte?]
:> It depends on the context - what you call a byte (assuming vaguely
:> orthodox historical usage) would often be called a "char" among
:> programmers. "Char" seems to be the single best replacement for byte
:> (in the sense of some bits representing a character).
: IMHO "char" is a very poor choice. How many bits are there in a char? 7
: (ASCII)? 8 (because it's handy to store a single char in a byte - I mean
: octet)? 16 (Unicode - one form anyway)? a variable number (UTF8) ? ... ?
I was "assuming vaguely orthodox historical usage". This is (I believe)
that described in "The New Hacker's Dictionary", whose definition of
"byte" begins:
``A unit of memory or data equal to the amount used to represent one
character; [...]''
In short the ambiguity you find distasteful is present in the main
definition of the term whose sense I was trying to capture.
: I'd say that "byte" should be taken to mean the smallest directly
: addressable storage unit of a computer's architecture [...]
That refers to *something* - but not what most sources I have seen call a
"byte". Almost always, the space required to represent a character is
mentioned in this context.
--
__________ http://alife.co.uk/ http://mandala.co.uk/
|im |yler [EMAIL PROTECTED] http://hex.org.uk/ http://atoms.org.uk/
------------------------------
From: Tom St Denis <[EMAIL PROTECTED]>
Subject: Re: Basic skills and equipment...
Date: Tue, 17 Oct 2000 12:13:46 GMT
In article <[EMAIL PROTECTED]>,
"Sam Simpson" <[EMAIL PROTECTED]> wrote:
> Tom St Denis <[EMAIL PROTECTED]> wrote in message
> news:8sh9i6$9j6$[EMAIL PROTECTED]...
>
> <SNIP>
>
> > Ok obviously you guys are just waiting to flame me at every chance.
> I
> > think if you want to get into crypto-math you should know very
> basic
> > terms like "ciphertext" or "salt". Otherwise what's the point?
>
> <SNIP>
>
> Tom, you're the most prolific poster in this forum and you sometimes
> shoot from the hip - are you really surprised that some people will
> disagree with you on occasion? I think you could quite correctly
> call Bobs comments "a flame", but he has problems being civil to most
> people here, so don't take personal offense.
True, I didn't take any offense. I just find it odd that he would
refute "read the faq" in sci.crypt.
Oh well, no biggie really. I am busy preparing my TC8 submission
(really cool cipher) for CHES'01 and I have high school to deal with.
So ... shall we let this topic die? hehehe
Tom
Sent via Deja.com http://www.deja.com/
Before you buy.
------------------------------
From: Tom St Denis <[EMAIL PROTECTED]>
Subject: Re: Crypto technology recommendations?
Date: Tue, 17 Oct 2000 12:12:01 GMT
In article <[EMAIL PROTECTED]>,
Wei Dai <[EMAIL PROTECTED]> wrote:
> In article <8s9jkg$g20$[EMAIL PROTECTED]>, [EMAIL PROTECTED] says...
> > Why? His C++ kit will not compile with DJGPP. Seems rather half-
assed
> > to me since it hasn't worked with DJGPP for other two years. As
far as
> > I know DJGPP is (like GCC) a "standard" compliant compiler. So it's
> > his code that makes use of some compiler specific thingy...
>
> Actually Crypto++ 3.2 compiles just fine with DJGPP 2.03. There is a
> linker issue, which you can work around by using the makefile at
> weidai.com/djgpp-Makefile. (It turns on DJGPP's support for weak
> symbols.)
Hmm, well I will give it a whirl this weekend.
Thanks for the update.
Tom
Sent via Deja.com http://www.deja.com/
Before you buy.
------------------------------
From: Tom St Denis <[EMAIL PROTECTED]>
Subject: Re: Smartcard, Mathematical Proof?
Date: Tue, 17 Oct 2000 12:14:56 GMT
In article <[EMAIL PROTECTED]>,
[EMAIL PROTECTED] wrote:
> Hi
>
> does somebody know the mathematical proof for
> whether a system with the smartcard is better
> protected than an equivalent system without
> the smartcard. I appreciate any comments and examples
> with formal proof for such systems.
>
> With best regards.
You mean as a login token or a "dongle"?
Dongles are stupid "snake oil" and login tokens are just physical
passwords. if it's used in the sense that having the card is the only
secret, then it can be quite secure. Otherwise....
Tom
Sent via Deja.com http://www.deja.com/
Before you buy.
------------------------------
From: Dima Pasechnik <[EMAIL PROTECTED]>
Crossposted-To: comp.theory,sci.math,sci.op-research
Subject: Re: A new paper claiming P=NP
Date: 17 Oct 2000 14:20:09 +0200
[EMAIL PROTECTED] writes:
> I have been following this thread for the last week.
> It seems like this paper has resisted the
> usenet kook police thus far, aside from minor
> errors which seem to have been explained.
> Does it have a real shot at proving
> P=NP?
>
> I was hoping its presence in comp.theory and
> sci.math would generate a lot more
> discussion about the actual content
> of the paper rather than side issues
> such as document formats,
> implications of P=NP, and the questioning
> of the relevance of asymptotics.
>
> I would appreciate it if someone
> who is qualified in this area could
> take a look at this paper
> and report their opinions to usenet.
>
Have you ever written a referee report on a paper submitted
to a journal? It can be a lot of work, and not very rewarding one.
As far as the preprint in question is concerned, it appears not
to meet the normal journal standards, as the consensus on
sci.op-research seems to be.
A (mild) reply from a good journal, should the preprint be submitted there,
would be -
"hardly readable, such and such things claimed are not proved.
a substantial rewrite is necessary..."
---
Dmitrii
http://ssor.twi.tudelft.nl/~dima/
------------------------------
From: Daniel Leonard <[EMAIL PROTECTED]>
Subject: Re: Works the md5 hash also for large datafiles (4GB) ?
Date: Tue, 17 Oct 2000 12:23:31 GMT
On Tue, 17 Oct 2000, Runu Knips wrote:
> [EMAIL PROTECTED] wrote:
> > I have to compare diskimages. To save diskspace I want to use
> > a hash (md5).
> >=20
> > Work md5 for such large files?
> > I know I would generate a 128bit signature, what I mean is, is
> > the probability that two different large files have the same
> > signature as low as for smaller files.
> >=20
> > In other words, is the algorthm of md5 only designed for "small"
> > files?
>=20
> AFAIK MD5, SHA-1, RIPE MD160 and Tiger/192 all work with 64 bit
> size counters. I guess SHA256 does, too.
But SHA384 and SHA512 works with 128 bits counters.
==========
Daniel L=E9onard
OGMP Informatics Division E-Mail: [EMAIL PROTECTED]
D=E9partement de Biochimie Tel : (514) 343-6111 ext 5149
Universit=E9 de Montr=E9al Fax : (514) 343-2210
Montr=E9al, Quebec Office: Pavillon Principal G-312
Canada H3C 3J7 WWW : http://megasun.bch.umontreal.ca/~leonard
------------------------------
From: Tom St Denis <[EMAIL PROTECTED]>
Subject: Re: Works the md5 hash also for large datafiles (4GB) ?
Date: Tue, 17 Oct 2000 12:16:38 GMT
In article <[EMAIL PROTECTED]>,
Runu Knips <[EMAIL PROTECTED]> wrote:
> [EMAIL PROTECTED] wrote:
> > I have to compare diskimages. To save diskspace I want to use
> > a hash (md5).
> >
> > Work md5 for such large files?
> > I know I would generate a 128bit signature, what I mean is, is
> > the probability that two different large files have the same
> > signature as low as for smaller files.
> >
> > In other words, is the algorthm of md5 only designed for "small"
> > files?
>
> AFAIK MD5, SHA-1, RIPE MD160 and Tiger/192 all work with 64 bit
> size counters. I guess SHA256 does, too.
SHA-512/384/256 all use the exact same MD-Strengthing as MD5 so yes,
they are 64-bit counters.
Tom
Sent via Deja.com http://www.deja.com/
Before you buy.
------------------------------
Date: Tue, 17 Oct 2000 14:00:04 +0100
From: Richard Heathfield <[EMAIL PROTECTED]>
Subject: Re: gender vs. sex [was Rijndael implementations]
wtshaw wrote:
>
> 40) *Quaver lazy, know God can't be a prude from His jinx.
Sadly, it took me an entire day (of elapsed time, I hasten to add) to
work this out. In an attempt to salvage some pride, I offer the
following newspaper headline:
Izvestia mixup after Rijndael cipher was broken by GCHQ.
--
Richard Heathfield
"Usenet is a strange place." - Dennis M Ritchie, 29 July 1999.
C FAQ: http://www.eskimo.com/~scs/C-faq/top.html
K&R Answers: http://users.powernet.co.uk/eton/kandr2/index.html
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