Cryptography-Digest Digest #137
Cryptography-Digest Digest #137, Volume #14 Fri, 13 Apr 01 21:13:00 EDT
Contents:
Re: Comment on SafeBoot's RC5 algorithm (Lawrence Kirby)
Re: Graphical representation of a public key (or fingerprint)? ("Paul Pires")
Re: Can this be done? ("Joris Dobbelsteen")
Re: NSA-Endorsed Schools have a Mediocre Internet Presence (Doug Stell)
Re: Graphical representation of a public key (or fingerprint)? (James Day)
Re: NSA-Endorsed Schools have a Mediocre Internet Presence (Mok-Kong Shen)
Re: How good is steganography in the real world? (wtshaw)
Re: Black white .gifs? (wtshaw)
Re: XOR TextBox Freeware: Very Lousy. ("Douglas A. Gwyn")
Re: Black white .gifs? (wtshaw)
Re: _"Good" school in Cryptography ("was" I got accepted) (David A Molnar)
please comment (Yechuri)
Re: please comment ("Tom St Denis")
Re: Big Number (Mark Wooding)
Re: please comment (Darren New)
Re: please comment ("Tom St Denis")
From: [EMAIL PROTECTED] (Lawrence Kirby)
Subject: Re: Comment on SafeBoot's RC5 algorithm
Date: Fri, 13 Apr 2001 16:22:40 GMT
Reply-To: [EMAIL PROTECTED]
In article KoGz6.46630$[EMAIL PROTECTED]
[EMAIL PROTECTED] "Tom St Denis" writes:
"Lawrence Kirby" [EMAIL PROTECTED] wrote in message
news:[EMAIL PROTECTED]...
In article [EMAIL PROTECTED] [EMAIL PROTECTED] "Marc"
writes:
cipher-block-chaining based on the sectors. The raw alg works at about
400MB/s (yes, 400 megabytes of data per second) on a 1ghz athelon in
W32.
The interesting thing is that my P3-800 FSB133 does hardly even read
more than 110 MB/s from RAM.
My old 200Mhz Ppro with EDO memory can manage up to about 250MB/sec
reading from memory so there is something very wrong there. :-) 133Mhz
SDRAM can manage about 1GB/sec and you should be able to realise at
least 700-800MB/sec reading, sometimes more.
If you can read real data at 800mb/sec then you're a god. Contrived
bandwidth tests are of theoretical interest only.
It depends, the actual test consisted of code that performed 1 read per cache
line in order to test memory performance. Code that does something simple
with the data should be able to manage this sort of performance using the
PIII's prefetch instructions so it should be quite possible for some forms
of hand-optimised code.
My IDE hd is supposed to read 40MB sec too but I only really get about
10MB/sec max during a read/seek test.
If you are using a benchmark that isn't measuring just transfer rate
you aren't going to get a figure that indicates just the transfer rate.
:-)
--
=
Lawrence Kirby | [EMAIL PROTECTED]
Wilts, England | [EMAIL PROTECTED]
=
--
From: "Paul Pires" [EMAIL PROTECTED]
Subject: Re: Graphical representation of a public key (or fingerprint)?
Date: Fri, 13 Apr 2001 13:13:01 -0700
Trevor L. Jackson, III [EMAIL PROTECTED] wrote in message
news:[EMAIL PROTECTED]...
Paul Pires wrote:
Mok-Kong Shen [EMAIL PROTECTED] wrote in message
news:[EMAIL PROTECTED]...
John Myre wrote:
I like this, but I'm not sure one face is enough. It only takes 33
bits or so to count every human face there is, and clearly some faces
look pretty much alike. (Granted, the humans that exist don't span the
potential faces. But the order-of-magnitude problem still exists.)
I am interested in the fact that a human face could be
characterized by as few as some thirty bits. Could you
please give a reference? Thanks.
I believe he said "33 bits to count" This is far different
than "33 bits to represent" 2^33 ~ 8.6 billion. Do we have
8.6 billion souls on this rock?
Anyway, I think it was a stab at setting an upper bound on
the keyspace size that that humans could probably discriminate
within. I don't think it had to do with the complexity of faces.
There's a hidden reliability problem here. It comes in two forms. The first form
is the
repeatability of recognizing a pattern that is or is not valid. A simpler example
is recognizing
colors. Humans can discriminate about 100,000 distinct colors in that they can tell
them apart.
But, this does not mean one can relibably encode ~17 bits of information within a
single color
sample. Think what you ate/drank/said/did/heard last night "colors" your perception
of the world?
Then the colors you see today won't match the colors you saw yesterday.
The second form is the transitivity of the pattern recognition. One persons ability
to discriminate
faces or colors may have the same size as anothers, but the sets of recognizable
patterns may not be
congruent.
Another point to remember. Subtle recognition of color, hue, taste, smell and texture
do not
Cryptography-Digest Digest #137
Cryptography-Digest Digest #137, Volume #12 Thu, 29 Jun 00 16:13:01 EDT
Contents:
Re: Dynamical Cryptography algorithm (Mark Wooding)
Re: what does it mean: "to find collision in bytes" ("CrakMan")
Re: very large primes ("Tony T. Warnock")
Re: very large primes ([EMAIL PROTECTED])
Re: Does anyone have code for generating primitive polynomials? (Mike Rosing)
Re: Hey Tom, you wanted to break it ! ;-) (Mike Rosing)
Re: It's been pretty quiet for some time... ("Joseph Ashwood")
Re: Idea or 3DES ("Joseph Ashwood")
Re: very large primes ([EMAIL PROTECTED])
Re: AES: It's been pretty quiet for some time... (wtshaw)
Re: Idea or 3DES (jungle)
Re: On a notation issue of Feistel ciphers (Mok-Kong Shen)
Re: Variability of chaining modes of block ciphers (Mok-Kong Shen)
Re: Variability of chaining modes of block ciphers (Mok-Kong Shen)
Re: Remark on practical predictability of sequences (Mok-Kong Shen)
Re: Idea or 3DES (jungle)
Re: AES: It's been pretty quiet for some time... (Mok-Kong Shen)
From: [EMAIL PROTECTED] (Mark Wooding)
Subject: Re: Dynamical Cryptography algorithm
Date: 29 Jun 2000 17:12:01 GMT
Sylvain Martinez [EMAIL PROTECTED] wrote:
so. Hence my assertion that you didn't want to answer it. Is my
logic faulty?
No, but I didn't see it that way. I was first thinking of "DES" because
I realised it was wrong I said nothing.
[...]
doesn't use factorials); you use a logical AND to do some passphrase
expansion, although this will cause a huge bias towards zero bits in
the result.
I am actually not only doing that :O)
Indeed not. But
Counterintuitively enough, designing ciphers isn't the right way to
learn cipher design. What you need to do is study other people's
designs, and their analysis. Read the AES entries -- particularly
Twofish and Rijndael -- for hints on presentation and analysis. See
also Schneier's self-study cryptanalysis course.
I do not totaly agree with you. It is like learning guitar.
There are similarities and differences. As a self-taught guitarist and
cryptographer (although far from perfect at either), I'll try to
describe them:
For instance, when you pick up a guitar and play it badly, it sounds
awful. You can tell this by listening, and do something to fix it, such
as changing your fingering or picking, or giving more practice time to a
tricky technique.
The important point is that you must have the ability to listen
critically to the notes and chords you're playing, so that you know when
you're doing something wrong.
Cipher design is a bit similar. Critical listening is the analogue of
cryptanalysis, where you attack your design, and find its flaws.
There are (at least) two differences.
* We all get exposed to lots of music throughout our lives. While
music varies between cultures, almost everyone develops an ability
to listen and appreciate music of some kind or other. We don't tend
to be exposed to ciphers to the same degree, and we don't acquire
the ability to analyse ciphers in that almost automatic way in which
we can criticise music. To take this analogy too far, someone who's
designing ciphers without understanding cryptanalysis is like
someone deaf trying to play a guitar.
* It only takes one person finding one problem with your cipher to
break it. It's as if, when you're playing music, you have to make
*everyone* happy at the same time.
you can take lessons and becoming good at it, or you can learn your
self. This will allow you to understand better some concepts. You would
still need to take proper lessons but if you've done that, let say, for
7 years you will then learn quicker.
In other words it is not a complete waste of time :O)
I don't suggest that it's impossible to learn cipher design without
being taught by someone. But there are right ways to learn and wrong
ways. Schneier's self-study course is a good pointer in the right
direction. See http://www.counterpane.com/self-study.html.
-- [mdw]
--
From: "CrakMan" [EMAIL PROTECTED]
Subject: Re: what does it mean: "to find collision in bytes"
Date: Thu, 29 Jun 2000 10:33:30 -0700
Another way for bytes to collide is when two people in the same office
decide to pick up and move their computers at the same time. They walk down
the hallway not looking where they are going and crash into one another...
That's another way...
JK :-)
--
CRAK Software
http://www.crak.com
Password Recovery Software
QuickBooks, Quicken, Access...More
Spam bait (credit E. Needham):
root@localhost
postmaster@localhost
admin@localhost
abuse@localhost
webmaster@localhost
[EMAIL PROTECTED]
[EMAIL PROTECTED]
[EMAIL PROTECTED]
tomstd [EMAIL PROTECTED] wrote in message
news:[EMAIL PROTECTED]...
"MP&q
Cryptography-Digest Digest #137
Cryptography-Digest Digest #137, Volume #10 Sun, 29 Aug 99 21:13:03 EDT
Contents:
Re: Can I export software that uses encryption as copy protection? (JPeschel)
Re: What if RSA / factoring really breaks? (Mok-Kong Shen)
Re: Q: Cross-covariance of independent RN sequences in practice (Mok-Kong Shen)
Re: Key Establishment Protocols - free chapter from Handbook of Applied Cryptography
(Mok-Kong Shen)
Re: What if RSA / factoring really breaks? (DJohn37050)
Re: What if RSA / factoring really breaks? (Boudewijn W. Ch. Visser)
Re: What if RSA / factoring really breaks? (David A Molnar)
Re: What if RSA / factoring really breaks? ([EMAIL PROTECTED])
Re: What if RSA / factoring really breaks? ("David J Whalen-Robinson")
Re: RC4 question (fungus)
Re: What if RSA / factoring really breaks? (David A Molnar)
Re: What if RSA / factoring really breaks? ("David J Whalen-Robinson")
Re: What if RSA / factoring really breaks? (Helger Lipmaa)
Re: What if RSA / factoring really breaks? (David Wagner)
Re: What if RSA / factoring really breaks? (Paul Rubin)
Re: What if RSA / factoring really breaks?
Re: Can I export software that uses encryption as copy protection? (Eric Lee Green)
Re: What if RSA / factoring really breaks? ([EMAIL PROTECTED])
Re: What if RSA / factoring really breaks? (DJohn37050)
From: [EMAIL PROTECTED] (JPeschel)
Subject: Re: Can I export software that uses encryption as copy protection?
Date: 29 Aug 1999 20:55:31 GMT
[EMAIL PROTECTED] (SCOTT19U.ZIP_GUY) writes:
Joe if one can legally export decrytion could one then export a decryption
only version of my source code with working executable. Of course there
may be a few beer drinking German that could be smart enough to reverse
engineer and come up with a program that did encryption based on his code.
BUt the infinite powers of the beer drinking mind are beyond my control.
IF yes I can export it. What is to keep me from exporting a part of
scott19r
the decryption portion only of a different program. But haveing the weakness
the the decyryption part of the source code. could be lefted in five minutes
by a Brit and used to create a full working copy of scott19u. Note I never
intended to export encryption (usiing only a small subset of CLintonian logic
which protects one from prejury). Yes some random thougfhts from to much
beer that I am sure I will forget when this hangover leaves
Nope, Dave, I don't think you can export a decryption-only version of
your source code. You should be able to export a binary that does
decryption only, but I don't know why you would want to.
A tall glass of vodka on ice will get rid of most beer induced hagovers.
Joe
__
Joe Peschel
D.O.E. SysWorks
http://members.aol.com/jpeschel/index.htm
__
--
From: Mok-Kong Shen [EMAIL PROTECTED]
Subject: Re: What if RSA / factoring really breaks?
Date: Sun, 29 Aug 1999 23:08:53 +0200
DJohn37050 schrieb:
The known best method to attack a generic RSA key is the GNFS. GNFS can also
be used to solve discrete logs (the p value of DSA). One choice would be to go
to ECC. I presented a paper at PKS '99 on future resiliency. See
www.certicom.com in the PKS '99 section for my (rudimentary) thoughts on this.
Isn't it that Shamir has in a recent paper shown the feasibility
of building a special machine to crack RSA? I haven't seen the
paper. How is that related to the above?
M. K. Shen
--
From: Mok-Kong Shen [EMAIL PROTECTED]
Subject: Re: Q: Cross-covariance of independent RN sequences in practice
Date: Sun, 29 Aug 1999 22:55:01 +0200
[EMAIL PROTECTED] schrieb:
Since independent random sequences can be made at widely separated places,
while many things have lower bounds due to imperfection, this is not one
of the stronger examples.
You would be surprised at how many decibels of separation are possible
between the left channel of my stereo system, and the right channel of
somebody else's stereo system in Nebraska.
Perhaps I have not expressed myself clear enough. I meant what
magnitude of the value of computed cross-covariance can be safely
considered to be 0 in practice (even though that is non-zero) and
hence assume that there is indeed independence.
M. K. Shen
--
From: Mok-Kong Shen [EMAIL PROTECTED]
Subject: Re: Key Establishment Protocols - free chapter from Handbook of Applied
Cryptography
Date: Sun, 29 Aug 1999 23:23:42 +0200
Alfred John Menezes wrote:
of the book will not be affected. Any comments on this publishing
experiment will be greatly appreciated.
I believe the experiment is successful. Those who can afford the price
at all will certainly buy a copy, for the printout is inconvenient
to handle. Th
Cryptography-Digest Digest #137
Cryptography-Digest Digest #137, Volume #9 Thu, 25 Feb 99 11:13:03 EST
Contents:
Re: Snake Oil (from the Feb 99 Crypto-Gram) (Lutz Donnerhacke)
Re: Testing Algorithms (Alan Braggins)
Re: Snake Oil (from the Feb 99 Crypto-Gram) ([EMAIL PROTECTED])
Re: What do you all think about the new cipher devised by a 16 year old? ("Vonnegut")
Re: Take my hand, PLEASE ([EMAIL PROTECTED])
Re: Define Randomness (R. Knauer)
Re: Testing Algorithms (Patrick Juola)
Re: Randomness based consciousness?. (Was: Re: *** Where Does The Randomness Come
From ?!? *** ) (R. Knauer)
Re: True Randomness - DOES NOT EXIST!!! (Coen Visser)
Re: Define Randomness (R. Knauer)
DSS Keys ("Nicholas Cole")
Re: Define Randomness (R. Knauer)
Re: Define Randomness (R. Knauer)
Re: Testing Algorithms (Patrick Juola)
Re: True Randomness - DOES NOT EXIST!!! (R. Knauer)
Re: Define Randomness (R. Knauer)
Re: RC4 40 bit compared to RC4 128 bit. (fungus)
Re: Testing Algorithms (fungus)
From: [EMAIL PROTECTED] (Lutz Donnerhacke)
Subject: Re: Snake Oil (from the Feb 99 Crypto-Gram)
Date: 25 Feb 1999 12:15:36 GMT
* Peter Gutmann wrote:
[EMAIL PROTECTED] (Lutz Donnerhacke) writes:
3) 1024 bits- "Military" grade, slow, highest security
That's why PGP 2.6.3(i)n changed this to:
1024 bit - User grade
1535 bit - SubCA and RA grade
2048 bit - CA grade
... which those for whom it's most important (nontechnical types) will have
absolutely no understanding of.
Should not. ;-)
Although the term "military-grade security"
is meaningless, it seems to be one of the better ways to tell J.Random Luser
that this is the strongest level of security available in a program.
Which will be wrong.
--
From: Alan Braggins [EMAIL PROTECTED]
Subject: Re: Testing Algorithms
Date: 25 Feb 1999 10:17:49 +
"Trevor Jackson, III" [EMAIL PROTECTED] writes:
A superstring computer is certainly conceivable with modern theory, given
some room for TBDs in the specs. But a computer that violates the speed
of light is in the same class as divine inspiration. If you assume any
rules you want then you can get any output you want. By tomorrow.
Once you assume you can violate light speed, you can get the answer
not merely tomorrow, but yesterday[1]. Then you needn't bother
calculating it before sending it back in time to yourself. On the
other hand your opponent can then go back in time and decide to send a
different message in the first place, so you still haven't cracked it.
[1] unless FTL is possible in some reference frames but not others
--
From: [EMAIL PROTECTED]
Subject: Re: Snake Oil (from the Feb 99 Crypto-Gram)
Date: 25 Feb 1999 12:39:18 GMT
PGP 5.0 has ressurected the term, however ...
3) 1024 bits- "Military" grade, slow, highest security
--
=/=/=/=/=/=/=/=/=/=/=/=/=/=/=/=/=/=/=/=/=/=/=/=/=/=/=/=/=/=/=/=/
Mark Andreas [EMAIL PROTECTED] http://www.sky.net/~voyageur
PGP key 77EF76B1 available via key server, finger or webpage
=\=\=\=\=\=\=\=\=\=\=\=\=\=\=\=\=\=\=\=\=\=\=\=\=\=\=\=\=\=\=\=\
--
From: "Vonnegut" [EMAIL PROTECTED]
Subject: Re: What do you all think about the new cipher devised by a 16 year old?
Date: Thu, 25 Feb 1999 08:10:19 -0500
It seems pretty simple. It uses a
2X2 matrices. I wonder how on earth can something so simple been
overlooked?
Even if she did find a new way to implement the matrices, I do know that I
have seen a simple public key encryption algorithm which used matrices in a
Pre-Calculus books.
The book suggested using a method for encoding letters to numbers in the
plain text. They used A=1, B=2, ' '(space)=0, but ASCII or any other
method would be fine. Anyhow, the numbers are popped into a matrix and
multiplied by a square matrix M, your public key. Obviously, the private
key you would use is the inverse of M. This is quite a simple problem for a
2x2 matrix, though, so I doubt this new algorithm is the same thing.
However, the method just explained is somewhat secure for matrices of order
higher than 10 or 20. Not only does it take a reasonably long amount of
time to find the inverse of such a matrix, but your program could always
swap certain columns of the output or add some constant matrix.
I don't know if anyone found this information useful, as I am only beginning
in this field. ( I just happen to 16, myself ) Please forgive me if this
is all basic stuff you all have seen before.
By the way, thanks for reminding me about that matrix idea. I have a snow
day today, so I think I'll write a C++ implementation of it. Anyone who
wants it can email me at :
[EMAIL PROTECTED]
If you just want the compiled program or source code please specify,
otherwise, I'll send both.
Later,
-Vonnegut
--
F
