Cryptography-Digest Digest #762, Volume #13 Wed, 28 Feb 01 07:13:01 EST
Contents:
Re: Sad news, Dr. Claude Shannon died over the weekend. ("Douglas A. Gwyn")
Re: Hash strength question (Benjamin Goldberg)
Re: Hash strength question ("Scott Fluhrer")
Re: encryption and information theory (Mok-Kong Shen)
Re: Sad news, Dr. Claude Shannon died over the weekend. (Dennis Ritchie)
Re: OverWrite freeware completely removes unwanted files from harddrive (Anthony
Stephen Szopa)
=> FBI easily cracks encryption ...? ("Open FleshWound")
Re: Sad news, Dr. Claude Shannon died over the weekend. (Volker Hetzer)
Re: OverWrite freeware completely removes unwanted files from (network_noadle)
Patches for CFS 1.3.3 (Matthias Bruestle)
philosophical question? (Peter Osborne)
Encryption on Palm ("dexMilano")
Re: Sad news, Dr. Claude Shannon died over the weekend. ("dexMilano")
Re: philosophical question? ("Dirk Van de moortel")
Re: => FBI easily cracks encryption ...? (Nemo psj)
----------------------------------------------------------------------------
From: "Douglas A. Gwyn" <[EMAIL PROTECTED]>
Subject: Re: Sad news, Dr. Claude Shannon died over the weekend.
Date: Wed, 28 Feb 2001 07:03:23 GMT
"John A. Malley" wrote:
> His work is profound and eye-opening.
Not to detract from Shannon's work and its undoubted impact, but for
fairness it should be noted that the impetus of many of his ideas
(logarithmic measures of information, for example) derived from work
of Turing et al.
------------------------------
From: Benjamin Goldberg <[EMAIL PROTECTED]>
Subject: Re: Hash strength question
Date: Wed, 28 Feb 2001 07:32:13 GMT
Bryan Olson wrote:
>
> Benjamin Goldberg wrote:
> >
> > Thanks! And while you're clearly right about the XOR method being
> > trivially insecure, since
> >
> > H("acegik") XOR H("bdfhjl") == H("bdfhjl") XOR H("acegik").
> >
> > What about if each hash chip is seeded with it's index:
> >
> > H(1||"acegik") XOR H(2||"bdfhjl")
> >
> > I think it is very unlikely that:
> >
> > H(1||"acegik") XOR H(2||"bdfhjl")
> > == H(1||"bdfhjl") XOR H(2||"acegik")
>
> It may be unlikely for current hash functions, and
> you could probably prove something about random functions,
> but collision resistance of the construct does not follow
> from collision resistance of H.
Hmm. If H can be modeled as a Random Function, and I make the following
definitions:
J(x) = H(1 || x)
K(x) = H(2 || x)
Then surely J and K can surely also be modeled as Random Functions.
Further, although both are related to H, they should be unrelated to
each other.
Perhaps to make you more comfortable, I should define them as:
J(x) = H("0" || x)
K(x) = H("00" || x)
This is identical to the definition above in a theoretical universe, but
may be significantly different in a practical one.
--
The difference between theory and practice is that in theory, theory and
practice are identical, but in practice, they are not.
------------------------------
From: "Scott Fluhrer" <[EMAIL PROTECTED]>
Subject: Re: Hash strength question
Date: Tue, 27 Feb 2001 23:41:28 -0800
Benjamin Goldberg <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]...
> Bryan Olson wrote:
> >
> > Benjamin Goldberg wrote:
> > >
> > > Thanks! And while you're clearly right about the XOR method being
> > > trivially insecure, since
> > >
> > > H("acegik") XOR H("bdfhjl") == H("bdfhjl") XOR H("acegik").
> > >
> > > What about if each hash chip is seeded with it's index:
> > >
> > > H(1||"acegik") XOR H(2||"bdfhjl")
> > >
> > > I think it is very unlikely that:
> > >
> > > H(1||"acegik") XOR H(2||"bdfhjl")
> > > == H(1||"bdfhjl") XOR H(2||"acegik")
> >
> > It may be unlikely for current hash functions, and
> > you could probably prove something about random functions,
> > but collision resistance of the construct does not follow
> > from collision resistance of H.
>
> Hmm. If H can be modeled as a Random Function, and I make the following
> definitions:
> J(x) = H(1 || x)
> K(x) = H(2 || x)
> Then surely J and K can surely also be modeled as Random Functions.
> Further, although both are related to H, they should be unrelated to
> each other.
However, if you ask my opinion (and I believe you did), you should stick to
the:
Hash( x ) = H( H( x_odd ) || H( x_even ) )
definition you proposed earlier, specifically because the proof that it is a
secure hash function (given earlier) relies on the assumption that H is a
secure hash function, and not the rather stronger assumption that H is a
random oracle.
>
> Perhaps to make you more comfortable, I should define them as:
> J(x) = H("0" || x)
> K(x) = H("00" || x)
> This is identical to the definition above in a theoretical universe, but
> may be significantly different in a practical one.
No, it is not identical, even in the theoretical universe. With this
definition, "0" and "011" hash to the same thing (all zeros):
Hash("0") = H("0" || "0" ) xor H( "00" || "" ) = 0
Hash("011") = H("0" || "01" ) xor H( "00" || "1" ) = 0
You do have to be careful with these things...
--
poncho
------------------------------
From: Mok-Kong Shen <[EMAIL PROTECTED]>
Subject: Re: encryption and information theory
Date: Wed, 28 Feb 2001 09:01:45 +0100
John Savard wrote:
>
[snip]
>
> More precisely: if the message contains N bits of information, and
> occupies M bits of bandwidth, and the K is K bits long, the entropy of
> the encrypted message is N+K bits, *or* M bits, whichever is less.
>
> In the case of RSA encryption, given that you know the public key, no
> increase of entropy takes place.
In the sense of crypto, entropy is related to the difficulty
for the opponent to decrypt, I suppose. How does one explain
that a key enhances entropy in the symmetric case but not in
the asymmetric case, as you stated above? Thanks.
M. K. Shen
------------------------------
From: Dennis Ritchie <[EMAIL PROTECTED]>
Subject: Re: Sad news, Dr. Claude Shannon died over the weekend.
Date: Wed, 28 Feb 2001 08:38:56 +0000
"Douglas A. Gwyn" wrote:
...
> Not to detract from Shannon's work and its undoubted impact, but for
> fairness it should be noted that the impetus of many of his ideas
> (logarithmic measures of information, for example) derived from work
> of Turing et al.
Et al., certainly, but how Turing? For the information theory
aspect, the main references in his paper are to Nyquist and to
Hartley.
Dennis
------------------------------
From: Anthony Stephen Szopa <[EMAIL PROTECTED]>
Crossposted-To: alt.hacker
Subject: Re: OverWrite freeware completely removes unwanted files from harddrive
Date: Wed, 28 Feb 2001 00:57:41 -0800
"Trevor L. Jackson, III" wrote:
>
> Anthony Stephen Szopa wrote:
>
> > "Trevor L. Jackson, III" wrote:
> > >
> > > Anthony Stephen Szopa wrote:
> > >
> > > > Michael Brown wrote:
> > > > >
> > > > > <SNIP>
> > > > > > >
> > > > > > > I checked the web pages, but I can't find any description for how the
> > > > > > >>>>>(SNIP SNIP)
> > >>>
> > >>>
> > > the OS might never write to the disk at all.
> >
> > I told you what the coded instructions are.
> >
> > You and others suggest that just maybe these coded instructions are
> > somehow not being carried out.
> >
> > You are suggesting that maybe sometimes they are and sometimes they
> > are not.
>
> No, I am telling you in no uncertain terms that the compiler's run-time library,
> the operating system, it's device drivers, the disk controller, and the disk drive
> are free to optimize their performance by eliminating redundant writes. If you
> read your compiler's documentation you will find that it eliminates "redundant
> stores" so that when you write "X = Y;" the compiler may decide that there is no
> need to bother. Redundant file writes can be optimized out of existence for
> exactly the same reason: executing the action is a waste of time.
>
> >
> >
> > Urban Legend or FUD.
>
> Facts appear to bother you. Perhaps you should seek professional counseling about
> that.
>
> >
> >
> > Either way, refer us to some research papers that clearly
> > address / demonstrate this.
>
> Hardly necessary. Simply read the documentation for DOS. The section on SMARTDRV
> covers write-behind caching (note that this program is not a disk cache, but a
> track buffer). Simply look up the term write behind caching and apply the
> resulting understanding to the question at hand.
>
> If you doubt the documentation you are free to test your own hardware. Simply
> write a tiny program that hammers on a single sector many times. If you find the
> program completes in less time than it takes your disk to rotate that number of
> times you will have proven that it did not write the targeted sector the indicated
> number of times.
>
> Note that the fact that you are so naive as to believe that the programs you write
> do what you want them to do rather than what you told them to do means that you are
> not yet ready to write software for any user other than yourself. You have much to
> learn. One of the things you lack is the understanding that the code that opens a
> file, writes to it, and closes it is not a series of commands, but a series of
> requests.
>
> Note further that sci.crypt is not an appropriate forum for further discussion of
> this topic.
>
> >
> >
> > This is no trivial matter.
>
> Of course it is.
Well I guess this comes down to what is redundant.
I say write binary 222 to location x then write binary 222 to
location x + 1, then write binary 222 to location x + 2, etc.
I cannot see how this can be redundant to a computer.
Each location is different.
But then you may have a tired ass computer.
Are you telling us that this example is an example of redundancy?
------------------------------
From: "Open FleshWound" <[EMAIL PROTECTED]>
Crossposted-To: alt.security.pgp,talk.politics.crypto
Subject: => FBI easily cracks encryption ...?
Date: Wed, 28 Feb 2001 02:12:35 -0700
FBI: Hanssen suspected he was under surveillance
february 27, 2001
Web posted at: 9:36 PM EST (0236 GMT)
>From staff and wire reports
WASHINGTON -- Accused spy Robert Hanssen suspected he was under government
surveillance, telling his
Russian contacts "something has aroused the sleeping tiger," the FBI said in an
affidavit released
Tuesday.
The comment came from a letter that FBI officials said was encrypted on a computer
diskette found in
a package -- taped and wrapped in a black plastic trash bag -- that Hanssen dropped
underneath a
foot bridge in a park in Northern Virginia, immediately before his arrest.
The FBI decrypted the letter and described it in an affidavit filed in support of its
search
warrant.
Hanssen, a 25-year veteran in the FBI and a counterintelligence expert, was arrested
February 18 and
charged with spying for the Soviet Union and later Russia over a period of 15 years,
dating back to
the waning days of the Cold War.
FBI Director Louis Freeh said Hanssen, 56, was paid $1.4 million in cash and diamonds
for passing
top-secret information to Russians.
He was arrested after FBI agents watched him allegedly drop off a package of
classified information
at a park near his northern Virginia home, which was to be picked up by his Russian
handlers.
The package and letter retrieved by authorities were meant for his Russian handlers,
FBI officials
said.
"Dear Friends," the letter reads, according to the affidavit. "I thank you for your
assistance these
many years. It seems, however, that my greatest utility to you has come to an end, and
it is time to
seclude myself from active service.
"Since communicating last, and one wonders if because of it, I have been promoted to a
higher
do-nothing senior executive job outside of regular access to information within the
counterintelligence program. It is as if I am being isolated. Furthermore, I believe I
have detected
repeated bursting radio signal emanations from my vehicle ... Something has aroused
the sleeping
tiger. Perhaps you know better than I."
Hanssen also said he strongly suspected the Russians "should have concerns for the
integrity of your
compartment concerning knowledge of my efforts on your behalf."
------------------------------
From: Volker Hetzer <[EMAIL PROTECTED]>
Subject: Re: Sad news, Dr. Claude Shannon died over the weekend.
Date: Wed, 28 Feb 2001 11:06:08 +0100
"John A. Malley" wrote:
>
> I heard on NPR today that Claude Shannon died this past weekend at the
> age of 84.
Wow, I didn't know that he was still around. Most other people
that founded a whole new science died centuries or even millenia ago.
I think I'll have a quiet beer on him this evening.
Greetings.
Volker
------------------------------
Crossposted-To: alt.hacker
From: network_noadle <[EMAIL PROTECTED]>
Subject: Re: OverWrite freeware completely removes unwanted files from
Date: Wed, 28 Feb 2001 09:58:21 +0000
On Wed, 28 Feb 2001, Anthony Stephen Szopa wrote:
<snipped for brevity>
> >
> > >
> > >
> > > This is no trivial matter.
> >
> > Of course it is.
>
>
> Well I guess this comes down to what is redundant.
>
> I say write binary 222 to location x then write binary 222 to
> location x + 1, then write binary 222 to location x + 2, etc.
>
> I cannot see how this can be redundant to a computer.
>
> Each location is different.
>
> But then you may have a tired ass computer.
>
> Are you telling us that this example is an example of redundancy?
>
At an earlier stage in this thread you stated that you overwrite
repeatedly. Unless you are forcing the OS to flush the write cache after
each write, it will be queued for later processing. Anywhere from seconds
to minutes may elapse between the scheduling of a write to the actual
performance, depending on the system loading at the time.
If you write to x, x+1, x+2 &c and then immediately begin again, writing a
new pattern to x, x+1, x+2 &c *WITHOUT FLUSHING THE WRITE CACHE FIRST*,
then the OS will optimise the first write instructions out of existence.
What would be the point of performing them when you immediately replace
them with something else? Repeat until end of program. The upshot is that
only the last pattern will get written. In a /really/ smart OS it will see
the delete instruction that follows the overwrite and optimise away the
last write instruction as well. Why bother to write to a file that has
just been deleted?
This is about overiding the OS' built in tendency to optimise hardware
access for performance. If you cannot understand this then I agree with
another poster: you are not ready to write software for release to the
public. If you don't like that evaluation, tough. It's a fact. Lack of
understanding of the subject matter doesn't excuse you from
responsibility, it just explains why you got it wrong.
REDO FROM START. Best advice you'll get from round here.
network_noadle
--
Bill: We are Microsoft.
Resistance is futile.
You will be migrated.
Me: Bill, meet Tux. Tux, eat Bill.
------------------------------
From: [EMAIL PROTECTED] (Matthias Bruestle)
Subject: Patches for CFS 1.3.3
Date: Wed, 28 Feb 2001 10:16:51 GMT
Mahlzeit
I've started with cfs-1.3.3bf added a SPEC file and did a few
modifications myself. I would like to integrate also the patches
from other people and make then this public.
So send me your patches!
Thanks
endergone Zwiebeltuete
--
PGP: SIG:C379A331 ENC:F47FA83D I LOVE MY PDP-11/34A, M70 and MicroVAXII!
--
"Many that live deserve death. And some die that deserve life. Can you give
that to them? Then be not too eager to deal out death in the name of justice,
fearing for your own safety. Even the wise cannot see all ends."
-- Gandalf, considering the ethical implications of aborting Gollum
------------------------------
From: Peter Osborne <[EMAIL PROTECTED]>
Crossposted-To: sci.crypt.random-numbers,de.sci.informatik.misc,sci.math
Subject: philosophical question?
Date: Wed, 28 Feb 2001 11:36:49 +0100
Hi there!
RANDOMNESS / RANDOM NUMBERS
Maybe that point is not that simple at all, maybe it concerns too
many topics like statistics, math, cryptanalysis and even religion...
As I dealed with cryptography and HRNG circuits, I often ask myself:
Is randomness a kind of information ?
Is it the highest density of information (that we are not able to
understand)?
Is it merely the opposite of information?
Can there be a fundamental difference between pseudo-randomness and
real randomness (e.g. generated by radioactive decay or thermal
noise), especially under these aspects mentioned above?
So, what do you think?
Peter
------------------------------
From: "dexMilano" <[EMAIL PROTECTED]>
Subject: Encryption on Palm
Date: Wed, 28 Feb 2001 11:38:29 +0100
Is there anyone developed an encrytpion library on Palm OS?
Is there some library available somewhere?
I did some job and I want to have a comparison with some "guru".
thx
dex
------------------------------
From: "dexMilano" <[EMAIL PROTECTED]>
Subject: Re: Sad news, Dr. Claude Shannon died over the weekend.
Date: Wed, 28 Feb 2001 12:00:32 +0100
Is there anyone who knows where to find a PDF version on the "Communications
Theory of Secrecy Systems"?
The one linked in not easily readable.
thx
dex
"John A. Malley" <[EMAIL PROTECTED]> ha scritto nel messaggio
news:[EMAIL PROTECTED]...
> I heard on NPR today that Claude Shannon died this past weekend at the
> age of 84.
>
> Claude E. Shannon was a pioneer in communications theory, computer
> science, cryptology, information theory and artificial intelligence.
> To me he is an Engineering Hero. His bio is on-line at AT&T Research
>
> http://www.research.att.com/~njas/doc/shannonbio.html
>
> Dr. Shannon's paper, "The Mathematical Theory of Communication", is
> perhaps one of the most important papers ever published in the 20th
> Century. And his follow-on paper, "Communications Theory of Secrecy
> Systems" ,is a must-read for all of us in this USENET group.
>
> Both papers are graciously provided on line, the "The Mathematical
> Theory of Communication" at
>
> http://cm.bell-labs.com/cm/ms/what/shannonday/paper.html
>
> and "Communications Theory of Secrecy Systems" at
>
> http://www3.edgenet.net/dcowley/docs.html
>
> His work is profound and eye-opening.
>
>
> John A. Malley
> [EMAIL PROTECTED]
------------------------------
From: "Dirk Van de moortel" <[EMAIL PROTECTED]>
Crossposted-To: sci.crypt.random-numbers,de.sci.informatik.misc,sci.math
Subject: Re: philosophical question?
Date: Wed, 28 Feb 2001 11:27:01 GMT
"Peter Osborne" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED]...
> Hi there!
>
> RANDOMNESS / RANDOM NUMBERS
>
> Maybe that point is not that simple at all, maybe it concerns too
> many topics like statistics, math, cryptanalysis and even religion...
>
> As I dealed with cryptography and HRNG circuits, I often ask myself:
>
> Is randomness a kind of information ?
> Is it the highest density of information (that we are not able to
> understand)?
> Is it merely the opposite of information?
>
> Can there be a fundamental difference between pseudo-randomness and
> real randomness (e.g. generated by radioactive decay or thermal
> noise), especially under these aspects mentioned above?
Not so philosophical: I think, if I remember well, that information can be
defined as something that provides an answer to a Yes-No question.
I don't think randomness can do this.
A bit more philosophical quote from Frank Zappa:
Information is not Knowledge
Knowledge is not Wisdom
Wisdom is not Truth
Truth is not Beauty
Beauty is not Love
Love is not Music
Music is the Best.
There's no link to randomness here, so it's off-topic, but I like it ;-)
Dirk Vdm
------------------------------
From: [EMAIL PROTECTED] (Nemo psj)
Date: 28 Feb 2001 11:43:55 GMT
Subject: Re: => FBI easily cracks encryption ...?
Makes you want to use undisclosed algorithms made with home grown stream
ciphers doesnt it.. Because you know if it has a password box or a source code
for it somewhere its security is basicly ZERO.
------------------------------
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