Cryptography-Digest Digest #316, Volume #12 Sun, 30 Jul 00 16:13:00 EDT
Contents:
Re: Encrypt string to produce a unique number (SCOTT19U.ZIP_GUY)
Re: Encrypt string to produce a unique number (Sundial Services)
Re: Encrypt string to produce a unique number ("yankee")
Re: Encrypt string to produce a unique number ("yankee")
Re: Encrypt string to produce a unique number ("yankee")
Re: Encrypt string to produce a unique number (Mok-Kong Shen)
Re: =?iso-8859-1?Q?Math=E9matics?= (Mok-Kong Shen)
Re: On granularity of encryption operations (Mok-Kong Shen)
Re: Reference to a public key technique in NYTimes (Mok-Kong Shen)
Re: Enigma with Transpostion (German Mechanisation) (Mok-Kong Shen)
Re: The Purple Cipher (World War II) (JimD)
encrypting folders in Windoze ([EMAIL PROTECTED])
Re: Encrypt string to produce a unique number (Boris Kazak)
Re: Skipjack and KEA test vectors ("Douglas A. Gwyn")
Re: substring reversal ("Douglas A. Gwyn")
Re: Combining bit sequences ("Douglas A. Gwyn")
Re: Encrypt string to produce a unique number ("Douglas A. Gwyn")
----------------------------------------------------------------------------
From: [EMAIL PROTECTED] (SCOTT19U.ZIP_GUY)
Subject: Re: Encrypt string to produce a unique number
Date: 30 Jul 2000 17:16:17 GMT
[EMAIL PROTECTED] (yankee) wrote in
<8m1mpc$2hh$[EMAIL PROTECTED]>:
>Is there any algorithm to produce a unqiue number based on a string .
>The string is except to have a maximum length of 30(the string is
>alphanumeric only) After "encryption" . It should result in a number
>length of not more than unsigned long which is about 10 .
>
>
>
>
You can use my adaptive huffman compression with a condition file
that consists of the characters allowed in the sting. This will
compress a short string quite well and maybe what you are looking
for.
David A. Scott
--
SCOTT19U.ZIP NOW AVAILABLE WORLD WIDE
http://www.jim.com/jamesd/Kong/scott19u.zip
Scott famous encryption website NOT FOR WIMPS **no JavaScript allowed**
http://members.xoom.com/ecil/index.htm
Scott rejected paper for the ACM
http://members.xoom.com/ecil/dspaper.htm
Scott famous Compression Page WIMPS allowed ** JavaScript OK**
http://members.xoom.com/ecil/compress.htm
**NOTE EMAIL address is for SPAMERS***
I leave you with this final thought from President Bill Clinton:
"The road to tyranny, we must never forget, begins with the destruction
of the truth."
------------------------------
Date: Sun, 30 Jul 2000 10:57:43 -0700
From: Sundial Services <[EMAIL PROTECTED]>
Reply-To: [EMAIL PROTECTED]
Subject: Re: Encrypt string to produce a unique number
To clarify the various responses you will get to this:
{1} An "encryption" function is obliged to return exactly the same
output as was given in the original input, if provided with the correct
"key." Encryption functions generally do not alter the length of their
data.
{2} A "compression" function seeks to reduce the size of the input
string, but in a "loss-less way," that is to say the exact input can be
recovered verbatim from the compressed output.
{3} A "hashing" function produces a smaller output based on its input.
The input cannot be derived from the output. Different hashing
functions exist with different objectives and for different purposes.
For example, a function used in a hash-lookup table wants to get good,
even coverage of all the "hash buckets," distributing values fairly
evenly among them. A cryptographic hash-function is more concerned with
ensuring that even the slightest change to the input will produce a
different hash-output, and that the hashing operation cannot be even
approximately reversed.
There are an endless number of hash algorithms that could be used
depending on your actual needs. A simple one is to simply sum-up the
ASCII values. (But 'Dad' and 'Add' would then produce exactly the same
hash-output.) Another might use a combination of the old reliables:
exclusive-or, shift, and and-masks.
Now, if your requirements are crytographic in nature, you ought not
"roll your own" function. You should employ one that is already
published.
>yankee wrote:
>
> Is there any algorithm to produce a unqiue number based on a string . The
> string is except to have a maximum length of 30(the string is alphanumeric
> only) After "encryption" . It should result in a number length of not more
> than unsigned long which is about 10.
------------------------------
From: "yankee" <[EMAIL PROTECTED]>
Subject: Re: Encrypt string to produce a unique number
Date: Mon, 31 Jul 2000 01:55:19 +0800
So where can I find the adaptive huffman compression with a condition file ?
Thanks
SCOTT19U.ZIP_GUY <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]...
> [EMAIL PROTECTED] (yankee) wrote in
> <8m1mpc$2hh$[EMAIL PROTECTED]>:
>
> >Is there any algorithm to produce a unqiue number based on a string .
> >The string is except to have a maximum length of 30(the string is
> >alphanumeric only) After "encryption" . It should result in a number
> >length of not more than unsigned long which is about 10 .
> >
> >
> >
> >
>
> You can use my adaptive huffman compression with a condition file
> that consists of the characters allowed in the sting. This will
> compress a short string quite well and maybe what you are looking
> for.
>
>
> David A. Scott
> --
> SCOTT19U.ZIP NOW AVAILABLE WORLD WIDE
> http://www.jim.com/jamesd/Kong/scott19u.zip
> Scott famous encryption website NOT FOR WIMPS **no JavaScript allowed**
> http://members.xoom.com/ecil/index.htm
> Scott rejected paper for the ACM
> http://members.xoom.com/ecil/dspaper.htm
> Scott famous Compression Page WIMPS allowed ** JavaScript OK**
> http://members.xoom.com/ecil/compress.htm
> **NOTE EMAIL address is for SPAMERS***
> I leave you with this final thought from President Bill Clinton:
> "The road to tyranny, we must never forget, begins with the destruction
> of the truth."
------------------------------
From: "yankee" <[EMAIL PROTECTED]>
Subject: Re: Encrypt string to produce a unique number
Date: Mon, 31 Jul 2000 02:01:35 +0800
You mention about MD5 and SHA . How is the code looks like and how does it
really works.
Thanks
James Pate Williams, Jr. <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]...
> On Mon, 31 Jul 2000 00:54:32 +0800, "yankee" <[EMAIL PROTECTED]>
> wrote:
>
> >Is there any algorithm to produce a unqiue number based on a string . The
> >string is except to have a maximum length of 30(the string is
alphanumeric
> >only) After "encryption" . It should result in a number length of not
more
> >than unsigned long which is about 10 .
> >
> A cryptographic hash function will convert a string of bytes into a
> number of certain fixed length:
>
> MD5 128-bit output (4 unsigned or signed longs on a 16-bit or 32-bit
> system)
> SHA-1 160-bit output (5 unsigned or signed longs on a 16-bit or 32-bit
> system)
>
> ==Pate Williams==
> [EMAIL PROTECTED]
> http://www.mindspring.com/~pate
>
------------------------------
From: "yankee" <[EMAIL PROTECTED]>
Subject: Re: Encrypt string to produce a unique number
Date: Mon, 31 Jul 2000 02:08:08 +0800
Thanks , you have a give me good understanding about all this stuff.
What I need is more to "hashing function" .
Actually , I have thought of summing up the ASCII value of the whole string
, but as you have said, the value produce will not be unique. Actually , the
easier the algorithm ,it will be more easy for me to understand. Do you have
any ideas how I can go about it , to hash a string of length 30 to digits of
max length 10 .
Thank you very much.
Sundial Services <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]...
> To clarify the various responses you will get to this:
>
> {1} An "encryption" function is obliged to return exactly the same
> output as was given in the original input, if provided with the correct
> "key." Encryption functions generally do not alter the length of their
> data.
>
> {2} A "compression" function seeks to reduce the size of the input
> string, but in a "loss-less way," that is to say the exact input can be
> recovered verbatim from the compressed output.
>
> {3} A "hashing" function produces a smaller output based on its input.
> The input cannot be derived from the output. Different hashing
> functions exist with different objectives and for different purposes.
> For example, a function used in a hash-lookup table wants to get good,
> even coverage of all the "hash buckets," distributing values fairly
> evenly among them. A cryptographic hash-function is more concerned with
> ensuring that even the slightest change to the input will produce a
> different hash-output, and that the hashing operation cannot be even
> approximately reversed.
>
> There are an endless number of hash algorithms that could be used
> depending on your actual needs. A simple one is to simply sum-up the
> ASCII values. (But 'Dad' and 'Add' would then produce exactly the same
> hash-output.) Another might use a combination of the old reliables:
> exclusive-or, shift, and and-masks.
>
> Now, if your requirements are crytographic in nature, you ought not
> "roll your own" function. You should employ one that is already
> published.
>
> >yankee wrote:
> >
> > Is there any algorithm to produce a unqiue number based on a string .
The
> > string is except to have a maximum length of 30(the string is
alphanumeric
> > only) After "encryption" . It should result in a number length of not
more
> > than unsigned long which is about 10.
------------------------------
From: Mok-Kong Shen <[EMAIL PROTECTED]>
Subject: Re: Encrypt string to produce a unique number
Date: Sun, 30 Jul 2000 20:43:52 +0200
yankee wrote:
> Is there any algorithm to produce a unqiue number based on a string . The
> string is except to have a maximum length of 30(the string is alphanumeric
> only) After "encryption" . It should result in a number length of not more
> than unsigned long which is about 10 .
The problem is a simple mathematical one and not related to
crypto. You have to do a computation yourself. If you have n
symbols, you can map these to [0, n-1]. Let b = n-1. You can map
any string of m symbols to a number of the form
a_0 + a_1*b + a_2*b^2 + .... + a_(m-1)*b^(m-1)
where 0 <= a_i < b. If the maximum number b^m -1 can be
represented on your computer as unsigned int, then you can
operate the representation of the string (in plain or encrypted
form) as unsigned int.
M. K. Shen
------------------------------
From: Mok-Kong Shen <[EMAIL PROTECTED]>
Subject: Re: =?iso-8859-1?Q?Math=E9matics?=
Date: Sun, 30 Jul 2000 20:45:17 +0200
Ioshua wrote:
> Does someone know MAPLE V.4 PRO?
You should address the question to sci.math.symbolic.
M. K. Shen
------------------------------
From: Mok-Kong Shen <[EMAIL PROTECTED]>
Subject: Re: On granularity of encryption operations
Date: Sun, 30 Jul 2000 20:44:51 +0200
Addendum:
I strongly believe that operations on larger units can have
significant benefits because these can have effects beyond
the boundaries of the blocks which the block cipher operate
and hence not achievable by these. Block chaining is in
fact a large granularity operation already widely employed.
Substitutions on units larger than bytes would involve too
large substitution tables and hence be impractical. A limited
substitution effect can however be achieved over a width of
m words, i.e. m*n bits, through employing a Hill cipher with
a matrix of size m and a modulus 2^n where n is the number
of bits in a computer word.
M. K. Shen
------------------------------
From: Mok-Kong Shen <[EMAIL PROTECTED]>
Subject: Re: Reference to a public key technique in NYTimes
Date: Sun, 30 Jul 2000 20:45:29 +0200
Johnny Bravo wrote:
> Play music, record music as it gets sent to speakers. The software
> needed for this is already around, I've used it to record a broadcast
> channel playing through WinAmp.
>
> "Impractical" and "Impossible" merely becomes inconvenient as the
> music pirates now have to actually play the song before converting to
> MP3 format.
Copying can't absolutely be prevented. One can similarly make
pirated copies of any book. New pieces of music can have sort of
copyright protection, however, as far as I know.
M. K. Shen
------------------------------
From: Mok-Kong Shen <[EMAIL PROTECTED]>
Subject: Re: Enigma with Transpostion (German Mechanisation)
Date: Sun, 30 Jul 2000 20:45:47 +0200
John Savard wrote:
> Mok-Kong Shen<[EMAIL PROTECTED]> wrote, in part:
>
> >This establishes that substituion
> >can't be achieved in general through transpositions (not even at
> >finer granularity, i.e. at the bit level).
>
> I certainly agree that substitution and transposition are two
> different things.
>
> However, if one uses a 5-bit code to represent the characters of a
> 32-letter alphabet, permuting the bits which represent a single
> character, say by the arrangement 51324, certainly would produce a
> substitution of sorts on the characters.
Yes. But that can produce only a limited set of particular substitutions
of characters. Given a substitution which is outside of that set, one
has no way of doing the same. On the other hand, if one can only
do substitution of bytes (because e.g. doing substitution of larger
units would involve too large tables), then transposition of bytes is
certainly not what is doable with the (given limited) substitution and
hence supplements that substitution.
M. K. Shen
------------------------------
From: [EMAIL PROTECTED] (JimD)
Subject: Re: The Purple Cipher (World War II)
Reply-To: JimD
Date: Sun, 30 Jul 2000 17:46:08 GMT
On Sun, 30 Jul 2000 04:34:05 GMT, [EMAIL PROTECTED] (John
Savard) wrote:
>On Thu, 27 Jul 2000 18:51:18 GMT, [EMAIL PROTECTED] (JimD)
>wrote, in part:
>
>>The Purple was a different animal altogether. Unless I'm mistaken
>>it was enciphered code and not a cipher.
>
>You are mistaken; or are you? I think you are thinking of JN-25, which
>was a code, with additive tables. But PURPLE messages did also include
>some codewords from a small code of common phrases; but their primary
>encryption was by a machine that behaved somewhat like a rotor
>machine.
...which was construced primarily from telephone switchgear (preselectors),
at least in the American version.
You're probably right. It's been some time since I re-read Kahn.
Nonetheless its breaking was a magnificent feat; often overshadowed
by the glamour of Enigma.
--
__________________________
Jim Dunnett.
g4rga at thersgb.net
------------------------------
From: [EMAIL PROTECTED]
Subject: encrypting folders in Windoze
Date: Sun, 30 Jul 2000 19:04:54 GMT
Can anyone share how they encrypt folders in Windoze? Winzip? I
basically just want to be able to lock folders and their contents
from snooping eyes.
Thanks, and my apologies if this is too basic.
------------------------------
From: Boris Kazak <[EMAIL PROTECTED]>
Reply-To: [EMAIL PROTECTED]
Subject: Re: Encrypt string to produce a unique number
Date: Sun, 30 Jul 2000 19:29:06 GMT
yankee wrote:
>
> Is there any algorithm to produce a unqiue number based on a string . The
> string is except to have a maximum length of 30(the string is alphanumeric
> only) After "encryption" . It should result in a number length of not more
> than unsigned long which is about 10 .
========================
Can you hold 3 watermelons on a palm of your right hand?
The obvious answer is "no", there are 2 watermelons too many,
they will fall to the ground.
An alphanumeric string of length 30 has about 62^30 possible
variants (52 letters + 10 digits). This amounts to ~ 10^50.
You are willing to compress it into a 10^10 (unsigned long).
Do you realize that you need a number at least 5 times longer?
Best wishes BNK
------------------------------
From: "Douglas A. Gwyn" <[EMAIL PROTECTED]>
Subject: Re: Skipjack and KEA test vectors
Date: Sun, 30 Jul 2000 15:35:41 -0400
Mark Wooding wrote:
> Usually at this point I'd be suspicious of my implementation. So I
> pulled Doug Gwyn's version which was posted to this very newsgroup not
> so very long ago, ...
Make sure you're using the second posting; the first was from an
intermediate stage of code development that I thought I had
deleted and it performed the computation incorrectly. If you
want a corrected version send me e-mail at [EMAIL PROTECTED]
------------------------------
From: "Douglas A. Gwyn" <[EMAIL PROTECTED]>
Subject: Re: substring reversal
Date: Sun, 30 Jul 2000 15:39:02 -0400
Mok-Kong Shen wrote:
> Boris Kazak wrote:
> > I would like to see a serious attempt at cracking a 480 character
> > long message processed first with 11-character Vigenere
> > substitution and then permuted through a 10x12 grille.
> I don't think that somebody will take up your challenge and
> do the work.
Indeed, unless there was something to gain by the exercise,
it would be too much work to be fun, but it is crackable in
a practical context (e.g. several messages with known
plaintexts of different lengths).
------------------------------
From: "Douglas A. Gwyn" <[EMAIL PROTECTED]>
Subject: Re: Combining bit sequences
Date: Sun, 30 Jul 2000 15:42:38 -0400
Mok-Kong Shen wrote:
> I should appreciate learning further ideas of bit sequence
> combinations that are not too complicated for implementations.
There are all sorts of ways of "combining" variables in expressions.
What other properties are required? For example, do you want to be
able to invert a transformation from one set of variable to another
using a fixed algorithm no matter what the values? Without further
constraints your question is essentially, what mathematics is
possible.
------------------------------
From: "Douglas A. Gwyn" <[EMAIL PROTECTED]>
Subject: Re: Encrypt string to produce a unique number
Date: Sun, 30 Jul 2000 16:00:03 -0400
yankee wrote:
> Is there any algorithm to produce a unqiue number based on a string.
> The string is except to have a maximum length of 30 (the string is
> alphanumeric only). After "encryption", it should result in a
> number length of not more than unsigned long which is about 10.
In Standard C, unsigned long must have at least 32 bits; you seem
to be measuring in terms of decimal digits, which is imprecise.
There are more than (26+26+10)^30 possible strings meeting the
constraints (that's just the number of strings of length exactly
30). High-school math can be used to determine that 179 bits are
required to uniquely represent every possible value in that range;
of course by the time you add in representations for lengths 0..29
the total is much larger (exercise: what is it?). Since this is
greater than 32, the answer to your question is "No".
The hashing schemes other responders have mentioned must produce
the *same* 32-bit result for numerous sets of *different* inputs.
Depending on your application, that might not be a *big* problem,
but in actual operation you need to allow for the possibility that
two different input strings will hash to the same value.
------------------------------
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