Cryptography-Digest Digest #474, Volume #11 Sun, 2 Apr 00 23:13:01 EDT
Contents:
Re: Magnetic Remenance on hard drives. (was: Re: Evidence Eliminator - (Guy Macon)
Re: Using Am-241 to generate random numbers (Gisle S�lensminde)
Beale 1 and 3 Not Ciphers at All? ("Steve Franklin")
Re: TEA? (Tom St Denis)
Re: Des security ? (Tom St Denis)
Re: I will make ANY software for ANYBODY (Paul Schlyter)
Re: Stolen Enigma (Paul Schlyter)
Re: Using Am-241 to generate random numbers (Guy Macon)
Re: Using Am-241 to generate random numbers (Guy Macon)
Re: Key exchange using Secret Key Encryption ([EMAIL PROTECTED])
Re: Disc encryption software question (Eli Akronym)
Re: Magnetic Remenance on hard drives. (was: Re: Evidence Eliminator - Who is trying
to silence our program? It's not working...) ("Lyalc")
----------------------------------------------------------------------------
From: [EMAIL PROTECTED] (Guy Macon)
Crossposted-To: alt.privacy,alt.security.pgp
Subject: Re: Magnetic Remenance on hard drives. (was: Re: Evidence Eliminator -
Date: 02 Apr 2000 19:27:58 EDT
In article <[EMAIL PROTECTED]>, [EMAIL PROTECTED] (Thor Arne Johansen) wrote:
>
>I would challenge anyone to produce evidence that overwritten data, can
>be recovered. There seem to be some sort of consensus that reading
>overwritten data can easily be recovered. Most of the descriptions on
>how to do this is quasi-science at the best, and mindless techno-ranting
>at the worst.
Absense of evidence is not evidence of absense.
There is good reason to believe that the evidence you seek is classified.
>Mr. Gutmans paper is the best description of secure deletion I've seen
>so far (even though I still think overwriting is a secure way to erase
>data from magnetic media). However the paper is not a writeup on
>successful recovery of overwritten data, it is merely describing some of
>the processes and techniques to consider.
>
>Why recovering overwritten data is almost impossible:
>NONLINEARITY, Spindle Jitter, Clock Jitter, PRML encoding, poor signal
>to noise, correlated noise.
These effects, when they happen during the original writing or the
attempted overwriting, make it *easier* to recover data. If the
overwriting bit is off center and only partially covers the original
bit, the job of recovery is made simpler.
These techniqes do not apply if you use the methods detailed by Peter
Gutmann in [ http://www.cs.auckland.ac.nz/~pgut001/secure_del.html ].
Magnetic force microscopy lacks nonlinearity, Spindle Jitter, Clock
Jitter, PRML encoding, poor signal to noise, and correlated noise.
>Now, this could also be judged as techno ranting :), but if you look
>into it, these things makes it incredibly hard (almost impossible), to
>recover overwritten data.
I have a lot of obsolete and partially related experience in this area
as an engineer who has worked with the original 30MB/30MB Winchester
mainframe disk drives, 9 track mainframe tape drives, timelapse video
recorders, phillips cassette data recorders, spacebourn data recorders
for the space shuttle, and most recently DVD-RAMs. None of this
experience is with modern disk drives, but I understand the basics,
and have recovered "erased" data from these various recoding devices
using fine iron powder and a good microscope. I have also failed to
recover the data many times. This opsolete technique wouldn't work
withy modern disk drives, of course - a quick calculation shows that
the features are too small for that. It is important to realize that
we had plenty of nonlinearity, Spindle Jitter, Clock Jitter, poor
signal to noise, and correlated noise, and that this did not prevent
recovery.
------------------------------
From: [EMAIL PROTECTED] (Gisle S�lensminde)
Subject: Re: Using Am-241 to generate random numbers
Date: 3 Apr 2000 01:54:48 +0200
In article <8c88uc$4gb$[EMAIL PROTECTED]>, Jed Rothwell wrote:
>Guy Macon wrote:
>
>> >Another rich source of random noise might be the human genome data.. . .
>>
>> This has the same flaw as usenet posts. An attacker might observe you and
>> your correspondent looking at the same section of the human genome and
>> downloading the same gene sequence. Unless you download the whole thing,
>> which is just as hard as downloading all usenet posts.
>
>Ah, I had in mind that you would purchase the entire genome set on high
>density DVDs. I believe it will be available in that medium. Probably
>expensive, I guess. I have no idea how many disks it would fill up. I
>suppose for that matter you could purchase 100 Hollywood movies on DVD and
>mix up the data streams, but I think the genome data looks more random to
>start with. Digitalized movies probably have a lot of structure. (The genome
>might also, for all I know.)
>
There is several problems with genomes in this respect. Large parts of a
genome has been duplicated during evolution, and are mutated copies other
part of the genome, so the genome has structure which one has to be aware
of, but it also contains lot of noise.
--
--
Gisle S�lensminde ( [EMAIL PROTECTED] )
ln -s /dev/null ~/.netscape/cookies
------------------------------
From: "Steve Franklin" <[EMAIL PROTECTED]>
Subject: Beale 1 and 3 Not Ciphers at All?
Date: Sun, 2 Apr 2000 19:53:58 -0400
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Has it occurred to anyone Beale 1 and 3 may be independent or combined maps
based on a two-dimensional grid, perhaps combined in some way with the DOI
substitution? I am particularly suspicious of the alphabetical strings.
These sound more graphical than textual to me. There ARE creeks central to
the geography of the area with gradual changes of elevation.
It also might be interesting to look at the A of the alphabetical sequence
as some kind of starting point: along the lines of X marks the spot?
--
Steve Franklin
"Many years ago, Warner tried to stop the Marx Brothers using the title
'Night in Casablanca', because it had made an earlier film called
'Casablanca'. At the time, Groucho wrote to Warner Brothers asking if they
thought they had the rights to 'Brothers', pointing out they had been
brothers before Warner had been invented, and that before them were the
Brothers Karamazov."
-- http://www.theregister.co.uk/
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<DIV><FONT color=3D#000000>Has it occurred to anyone Beale 1 and 3 may =
be=20
independent or combined maps based on a two-dimensional grid, perhaps =
combined=20
in some way with the DOI substitution? I am particularly suspicious of =
the=20
alphabetical strings. These sound more graphical than textual to me. =
There ARE=20
creeks central to the geography of the area with gradual changes of=20
elevation.</FONT></DIV>
<DIV> </DIV>
<DIV>It also might be interesting to look at the A of the alphabetical =
sequence=20
as some kind of starting point: along the lines of X marks the =
spot?</DIV>
<DIV><FONT color=3D#000000><BR>-- <BR>Steve Franklin</FONT></DIV>
<DIV> </DIV>
<DIV><FONT color=3D#000000>"Many years ago, Warner tried to stop the =
Marx Brothers=20
using the title 'Night in Casablanca', because it had made an earlier =
film=20
called 'Casablanca'. At the time, Groucho wrote to Warner Brothers =
asking if=20
they thought they had the rights to 'Brothers', pointing out they had =
been=20
brothers before Warner had been invented, and that before them were the =
Brothers=20
Karamazov." </FONT></DIV>
<DIV> </DIV>
<DIV><FONT color=3D#000000>-- <A=20
href=3D"http://www.theregister.co.uk/">http://www.theregister.co.uk/</A><=
/FONT></DIV>
<DIV> </DIV>
<DIV><FONT color=3D#000000>____</FONT></DIV></BODY></HTML>
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------------------------------
From: Tom St Denis <[EMAIL PROTECTED]>
Subject: Re: TEA?
Date: Mon, 03 Apr 2000 00:12:44 GMT
Simon Johnson wrote:
>
> Would a modified version of TEA, using a 16-bit block, and 32-bit key,be
> proportionally as strong as its 64-bit block, 128-bit key counterpart?
>
> Secondly, Is the addition mod 2^32 in TEA?
Well no, cuz a 32 bit key is 2^96 times easier to solve, so it's not
proportional based on size [well it's exponential]. And it would be
easy to attack such a variant.
And yes the addition is taken modulo 2^32.
Tom
------------------------------
From: Tom St Denis <[EMAIL PROTECTED]>
Subject: Re: Des security ?
Date: Mon, 03 Apr 2000 00:14:25 GMT
schack01 wrote:
>
> I most admit that im a newbie in crytology!
>
> Is there any weakness of des algoritm
> ( standard 56 bit key, 64 bit plain & cipher block )
>
> Ie all "ff" or all "00" plain data weakness ?
You are thinking of weak keys, there are about 20 or so weak keys out of
the lot [2^56]. There are complimentary keys as well.
> Is brute-force the only known solution to find a key ?
Not only known, but only practical solution. Linear and Differential
cryptanalysis do work against the cipher, but are far from practical.
> In brute-force, are there any way of reduce the 2^56 rounds ?
> Ive heard it can be broken down to 2^48 rounds , true ?
You are thinking of work factor, DES always has 16 rounds. The best I
think is around 2^41 with tons of plaintext/ciphertext.
Tom
------------------------------
From: [EMAIL PROTECTED] (Paul Schlyter)
Subject: Re: I will make ANY software for ANYBODY
Date: 3 Apr 2000 00:35:24 +0200
In article <[EMAIL PROTECTED]>,
ECN UltraTrader <[EMAIL PROTECTED]> Wrote:
> I manage a VAST group of programmers specializing in all fields of
> software development. If you have an idea for software that you would
> like to develop or are currently working on software but would like
> to save time & money, I can help. I offer the CHEAPEST software
> development rates in the United States. I can help you in developing
> ANY type of software with any provisions you may have
> (confidentiality, time limitations, etc). If you are interested,
> email me, and I will personally send you more information.
Thanks. I'd like the Windows-2000 operating system ported to the
ENIAC. I'd like it to be finished the day after tomorrow, and this
project should cost no more than $2. I request it to be delivered on
ENIAC-readable paper tape. No bugs will be tolerated.
I'm looking forward to cooperate with you. If you manage this
project, on time and within budget, I have some other, bigger,
projects in the pipeline -- or else I'll have to find someone
else to do them....
--
================================================================
Paul Schlyter, Swedish Amateur Astronomer's Society (SAAF)
Grev Turegatan 40, S-114 38 Stockholm, SWEDEN
e-mail: pausch at saaf dot se or paul.schlyter at ausys dot se
WWW: http://hotel04.ausys.se/pausch http://welcome.to/pausch
------------------------------
From: [EMAIL PROTECTED] (Paul Schlyter)
Subject: Re: Stolen Enigma
Date: 3 Apr 2000 00:35:47 +0200
In article <2eJF4.5455$[EMAIL PROTECTED]>,
Gary Watson <[EMAIL PROTECTED]> wrote:
> CNN is reporting that someone has stolen the Enigma machine from the
> Blechley Park exhibit in the UK. They say it's one of 3 in the world.
> Although it's a fairly obnoxious crime, you would think that they would
> padlock something so valuable before opening the place to the public.
Was it stolen on 1 april? :-)
--
================================================================
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] (Guy Macon)
Subject: Re: Using Am-241 to generate random numbers
Date: 02 Apr 2000 20:24:52 EDT
In article <[EMAIL PROTECTED]>, [EMAIL PROTECTED] (Jerry
Coffin) wrote:
>
>> I still don't see the advantages of using a telescope. Why not
>> use one of the many cheaper alternative keyspaces that both parties
>> can access?
>
>I honestly don't either -- when I entered this particular thread, it
>was only to comment that IF you decided to do this, it seemed to me
>that an optical telescope and a CCD camera would be a lot more
>practical than trying to build your own radio-telescope. I still
>think that much is true, but I'll openly admit that the whole basic
>notion seems highly impractical at best -- I certainly wouldn't plan
>on using it for any critical communication or anything like that.
Yes, but it's fun to think about. I believe that a small
radiotelescope would be cheaper than a a telescope. All
you need is a parabolic dish and a wideband reciever.
>In fairness to the question I originally addressed, a radio-telescope
>probably would have one advantage: a radio-telescope would be able to
>collect input even in weather that prevented using an optical
>telescope.
Good point! It also can run longer between servicing (telescopes get
dirty lenses or drty tranparent covers, antenna work when dirty).
Here's an idea...
In 1957, strange radio signals were found to come from the planet Jupiter,
greatly puzzling radio astronomers. The source turned out to be the
planet's immense radiation belt. The fact that some of the emissions
were found to be controlled by the position of the satellite Io is
probably related to the electrical currents linking Io to Jupiter.
These might be a good source for the signals we are discussing.
http://fiwfds01.tu-graz.ac.at/ijw/
Related links:
http://w1wqm.org/ggs/Education/wenpart2.html
http://radiojove.gsfc.nasa.gov/
http://www.supercomp.org/sc95/proceedings/568_CPOR/PENN_HL.HTM
http://www.faqs.org/faqs/astronomy/faq/part6/section-13.html
http://www.triax.com/vlfradio/wr3gde.htm
------------------------------
From: [EMAIL PROTECTED] (Guy Macon)
Subject: Re: Using Am-241 to generate random numbers
Date: 02 Apr 2000 20:35:46 EDT
In article <8c88uc$4gb$[EMAIL PROTECTED]>, [EMAIL PROTECTED]
(Jed Rothwell) wrote:
>
>Guy Macon wrote:
>
>> [1] A very large collection of keys that are freely accessable by anyone
>> (including any attacker) who wishes access. These could be stars,
>> pages from published books, usenet posts, etc.
>
>Actually, cosmic noise would *not* be available after the fact, an important
>point. It is not recorded anywhere, so if the attacker misses it, it is gone
>forever. Pages from books and usenet posts stick around and might be
>recovered later. If someone told the attacker the key a week after he
>intercepted the message, and the one-time pad was a usenet message, he could
>probably did it up. If the one-time pad was a star at a given location in
>the sky, even after he learned the coordinates it would be too late.
AHA! I see the light! This is indeed an important point. Nobody that
I know of records the whole set of signals that you can choose from
SETI@home records those that the arecibo radiotelescope is aimed at,
so you might wish to avoid those locations. If it weren't for the
idea of an attacker reading the data you recieve from the internet,
joining SETI@ home and using their data would be a good source of
data. (1,873,928 users have processed 100,153,045 work units so
far - and I am in the top 1%) [ http://setiathome.ssl.berkeley.edu/ ]
------------------------------
From: [EMAIL PROTECTED]
Subject: Re: Key exchange using Secret Key Encryption
Date: Mon, 03 Apr 2000 01:02:15 GMT
In article <VKTE4.59595$[EMAIL PROTECTED]>,
"Lyalc" <[EMAIL PROTECTED]> wrote:
> Provided an initial secret key can be passed securely enoug for the
purpose,
> a practically infinite number of unique secret keys can be used,
uniqe to
> each message.
> See Ansi X9 or ISO 8583.
> If that method is not operationaly reliable for the purpose, we have
an
> extension to those methods that does provide relaibility.
> Lyal
>
I know in ISO8583 messages the the PIN Block is encrypted by a session
key. But as you've pointed out the 0800 message for key exchange
requires you to have your KEK (Key for Key Exchange) established before
hand.
As I have mentioned in another posting, I was hoping there was a Messay-
Omura (or similar) protocol defined for Symmetric Key encryption.
Petang
Sent via Deja.com http://www.deja.com/
Before you buy.
------------------------------
From: [EMAIL PROTECTED] (Eli Akronym)
Subject: Re: Disc encryption software question
Date: Mon, 03 Apr 2000 01:29:46 GMT
"DIAMOND Mark R" <[EMAIL PROTECTED]> wrote:
>I hope this is not an inappropriate place for the following question.
>
>Does anyone know of a review of the software "PC Safe", a disc encryption
>package. I'm looking for something which will tell me how secure the
>encryption itself is, and whether its security depends only on not being
>able to have extended access to the hard disc (say by just pulling it out
>of the old machine and putting it as a non-boot drive into a new machine).
>I saw the software advertised in a professional (non-computing) magazine as
>a method of securing the confidentiality of patient records.
As far as I know, the only disk encryption programs available that have
open source code and verifiable integrity are Scramdisk and PGPDisk. All
other disk encryption programs should be considered worthless.
--
"Eli Akronym" is actually 9240 738165 <[EMAIL PROTECTED]>.
012 3456789 <- Use this key to decode my email address and name.
Play Five by Five Poker at http://www.5X5poker.com.
------------------------------
From: "Lyalc" <[EMAIL PROTECTED]>
Crossposted-To: alt.privacy,alt.security.pgp
Subject: Re: Magnetic Remenance on hard drives. (was: Re: Evidence Eliminator - Who is
trying to silence our program? It's not working...)
Date: Mon, 3 Apr 2000 12:26:24 +1000
All things are possible, usually just a matter of the available money to
dedicate to the task.
And on that basis, national security agencies usually have the need, and
capability.
Lyal
Thor Arne Johansen wrote in message <[EMAIL PROTECTED]>...
>Hello all,
>
>"Thomas J. Boschloo" wrote:
>>
>> EE Support wrote:
>> >
>> > We contend it does not. Overwriting all zeros practically trashes
>> > files on the disk.
>> >
>> > Can you prove us wrong? Is there any method to simply and reliably
>> > decode from any disk surface the primary 0/1 patterns from RLL, etc
>> > encoding, after a single zero overwrite? We think there is none.
>> > Please prove us wrong and we will beat it.
>>
>
>I agree 100%
>
>
>> Maybe the area close to the written track will still get magnetized by
>> the previous data, but you can't just set a treshold. You'll have to set
>> at least three treshold. One for going from 0->0 (very low magnetic
>> treshold), 0->1 (higher), 1->0 (still higher depending on time of last
>> wipe) and 1-1 (highest).
>
>High intersymbol inteference (ISI) will make this very hard. Disks use
>complex modulation/encoding schemes to handle this. (PRML/DFE).
>
>>
>> Hope this makes sense to the guys at sci.crypt and I am sure we'll hear
>> if I just had a brain fart.
>>
>> > (Disks
>> > >generally use some form of run-length limited encoding). To handle
all
>> > >possible disk encoding schemes types requires a particular sequence of
35
>> > >overwrite passes. You could reduce this if you knew the which disk
encoding
>> > >scheme was used (1,7)RLL, (2,7)RLL or MFM. If you want to know about
>> > >overwriting data or how easy it is to recover overwritten data I can
>> > >recommend the following paper.
>
>I would challenge anyone to produce evidence that overwritten data, can
>be recovered. There seem to be some sort of consensus that reading
>overwritten data can easily be recovered. Most of the descriptions on
>how to do this is quasi-science at the best, and mindless techno-ranting
>at the worst.
>
>Mr. Gutmans paper is the best description of secure deletion I've seen
>so far (even though I still think overwriting is a secure way to erase
>data from magnetic media). However the paper is not a writeup on
>successful recovery of overwritten data, it is merely describing some of
>the processes and techniques to consider.
>
>Why recovering overwritten data is almost impossible:
>NONLINEARITY, Spindle Jitter, Clock Jitter, PRML encoding, poor signal
>to noise, correlated noise.
>
>Now, this could also be judged as techno ranting :), but if you look
>into it, these things makes it incredibly hard (almost impossible), to
>recover overwritten data.
>
>
>> > >
>> > >http://www.cs.auckland.ac.nz/~pgut001/secure_del.html
>> > >
>> > >Don't buy or write a secure file deletion program until you've read
it.
>> > >
>
>Best regards,
>
>Thor Arne Johansen
------------------------------
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