Cryptography-Digest Digest #409, Volume #12 Fri, 11 Aug 00 05:13:00 EDT
Contents:
Re: Random Number Generator ([EMAIL PROTECTED])
Re: 1-time pad is not secure... (Guy Macon)
Re: I need lots of help ("kihdip")
Re: 1-time pad is not secure... (Guy Macon)
Re: Destruction of CDs (Guy Macon)
Re: Destruction of CDs (Guy Macon)
Copyright isue - SERPENT ("kihdip")
Re: Destruction of CDs (Guy Macon)
Cryptography FAQ (01/10: Overview) ([EMAIL PROTECTED])
Cryptography FAQ (02/10: Net Etiquette) ([EMAIL PROTECTED])
----------------------------------------------------------------------------
From: [EMAIL PROTECTED]
Subject: Re: Random Number Generator
Date: Fri, 11 Aug 2000 07:57:36 GMT
In article <[EMAIL PROTECTED]>,
Jerry Coffin <[EMAIL PROTECTED]> wrote:
> In article <8mtu40$9ck$[EMAIL PROTECTED]>, [EMAIL PROTECTED]
> says...
> > Alex Random Number Generator
> >
> > The objective of this algorithm is to map finite
> > key/seed to an infinite sequence of random bytes.
>
> This, of course, is impossible.
Do you think that there is no mapping of finite sets of natural
numbers into set of infinite sets of natural numbers?
Please evaluate this algorithm and you will believe.
>
> > - 16 byte Key/Seed
> > - 57% Avalanche Effect
> > - 760Kbyte/sec performance
> > - 64 Kbyte generated random string shows Null ZIP
> > compression
>
> A 16-byte key is large enough that although the sequence must
> eventually repeat, it shouldn't happen soon enough to care about.
> We've already gone over (in almost ridiculous detail) how stupid it
> is to make statements about performance without qualifying the
> statement as to the situation in which that particular level of
> performance was obtained. Avalanche normally applies to ciphers, not
> PRNGs, so it's hard to even guess at what you mean by "57% avalanche
> effect", though unless you're measuring something _really_ unusual,
> 57% is probably a pretty BAD number to get: for most obvious things
> you'd measure, you'd want outputs as close to either 50 or 100% as
> possible, and only numbers within .001 or so of those would be good
> enough to keep from rejecting the generator outright.
>
Thank you. Please let to do some more investigations.
> > - The probability to find in random sequence 0/1
> > value bits is exactly 50%
>
> This shows a lack of bias, but that's a long ways from being a
> comprehensive test of a PRNG.
>
Please check it yourelf.
> You PRNG fails some of the FIPS 140-2 tests fairly regularly. It
> fails quite a few of the DieHard tests very consistently. Your PRNG
> is clearly NOT suitable for cryptographic use.
It is only your assumption. Let us proof it.
Regards.
Alex.
>
> --
> Later,
> Jerry.
>
> The Universe is a figment of its own imagination.
>
Sent via Deja.com http://www.deja.com/
Before you buy.
------------------------------
From: [EMAIL PROTECTED] (Guy Macon)
Subject: Re: 1-time pad is not secure...
Date: 11 Aug 2000 08:11:54 GMT
fvw wrote:
>
>
><8mu3ne$[EMAIL PROTECTED]> ([EMAIL PROTECTED]):
>>OTP, for example, is provably insecure against the "point a gun
>>at the sender and politely ask him for the key" class of attacks.
>
>Actually, it's secure against that too. You can give them whatever
>plaintext you like by modifying your key. That's part of the reason
>why they're so loved.
Ooh! That's a great idea! One would have to plan ahead, of course.
------------------------------
From: "kihdip" <[EMAIL PROTECTED]>
Subject: Re: I need lots of help
Date: Fri, 11 Aug 2000 10:12:43 +0200
Try this link:
http://www.cacr.math.uwaterloo.ca/hac/
Here you'll find the book 'Handbook of Applied Cryptography' to download.
This book handles the basics in cryptography.
I will suggest chapters 1, 4, 6, 7 and 8.
Kim
[EMAIL PROTECTED] wrote in message
<[EMAIL PROTECTED]>...
Hi!
I'm new to
------------------------------
From: [EMAIL PROTECTED] (Guy Macon)
Subject: Re: 1-time pad is not secure...
Date: 11 Aug 2000 08:16:06 GMT
Douglas A. Gwyn wrote:
>
>
>Guy Macon wrote:
>> ...Close... ...so very close... Actually, OTP is secure against
>> being decoded by cryptanalysis if the numbers are unpredictable,
>> which is a weaker claim than random. For example, chaotic
>> systems are often unpredictable without being at all random.
>
>No, you have overstated it. Individual outputs of a chaotic
>process might very well be "unpredictable" in some sense, but
>there could still be strong statistical correlations among
>them that could be exploited by a cryptanalyst. (For example,
>every 10th value might be close to the value 10 iterations
>previous.) "Patternless" might have been a better description.
Point well taken. Thanks!
------------------------------
From: [EMAIL PROTECTED] (Guy Macon)
Subject: Re: Destruction of CDs
Date: 11 Aug 2000 08:23:03 GMT
Thomas Kellar wrote:
>
>
>There was a thread on this topic a couple of weeks ago.
>I received an advertisement for a device that shreds
>CDs. If anyone is interested the company name/address is
>
>Schleicher & Co. of America, Inc.
>5715 Clyde Rhyne Dr.
>Sanford, NC 27330-9909
>
>ph: 1 800 775 7570 email: [EMAIL PROTECTED]
>
>They claim their "501 CD shredder" can eliminate 800 to
>1200 CDs or credit cards per hour.
>
>A disinterested party. (Actually uninterested, I would burn them
>myself.)
I have one in my lab. It doesn't chop them fione enough for
crypto.
------------------------------
From: [EMAIL PROTECTED] (Guy Macon)
Subject: Re: Destruction of CDs
Date: 11 Aug 2000 08:25:15 GMT
Joseph Ashwood wrote:
>
>
>From a theoretic standpoint a magnet could have a detrimental effect on a
>cd,
My replication line only deposits aluminum or Gold. Which of these
do you think the magnet will attract?
------------------------------
From: "kihdip" <[EMAIL PROTECTED]>
Subject: Copyright isue - SERPENT
Date: Fri, 11 Aug 2000 10:27:08 +0200
A candidate for AES has to be free for everybody to use, but is it correct
that SERPENT has some limitations in implementations because of a copyright
??
If so, how much of the SERPENT implementation does this copyright involve ??
Kim
------------------------------
From: [EMAIL PROTECTED] (Guy Macon)
Subject: Re: Destruction of CDs
Date: 11 Aug 2000 08:28:11 GMT
Mok-Kong Shen wrote:
>
>Mickey McInnis wrote:
>>
>
>> Melting/burning would be better, but I would be concerned about toxic
>> byproducts. Stir the resultant puddle or ashes.
>
>Dumb question: Of what kind of chemical materials are CDs made?
>
>M. K. Shen
The only dumb question is the one you don't ask.
Mostly polycarbonate. A bit of UV-Cure laquer.
Maybe some label ink. A layer of Gold or Aluminum
so thin that you can see trhough it.
------------------------------
Crossposted-To: talk.politics.crypto,sci.answers,news.answers,talk.answers
Subject: Cryptography FAQ (01/10: Overview)
From: [EMAIL PROTECTED]
Reply-To: [EMAIL PROTECTED]
Date: 11 Aug 2000 08:44:18 GMT
Archive-name: cryptography-faq/part01
Last-modified: 1999/06/27
This is the first of ten parts of the sci.crypt FAQ. The parts are
mostly independent, but you should read this part before the rest. We
don't have the time to send out missing parts by mail, so don't ask.
Notes such as ``[KAH67]'' refer to the reference list in the last part.
Disclaimer: This document is the product of the Crypt Cabal, a secret
society which serves the National Secu---uh, no. Seriously, we're the
good guys, and we've done what we can to ensure the completeness and
accuracy of this document, but in a field of military and commercial
importance like cryptography you have to expect that some people and
organizations consider their interests more important than open
scientific discussion. Trust only what you can verify firsthand.
And don't sue us.
Many people have contributed to this FAQ. In alphabetical order:
Eric Bach, Steve Bellovin, Dan Bernstein, Nelson Bolyard, Carl Ellison,
Jim Gillogly, Mike Gleason, Doug Gwyn, Luke O'Connor, Tony Patti,
William Setzer. We apologize for any omissions.
Archives: sci.crypt has been archived since October 1991 on
ripem.msu.edu, though these archives are available only to U.S. and
Canadian users. Another site is rpub.cl.msu.edu in /pub/crypt/sci.crypt/
from Jan 1992.
The sections of this FAQ are available via anonymous FTP to rtfm.mit.edu
as /pub/usenet/news.answers/cryptography-faq/part[xx]. The Cryptography
FAQ is posted to the newsgroups sci.crypt, talk.politics.crypto,
sci.answers, and news.answers every 21 days.
The fields `Last-modified' and `Version' at the top of each part track
revisions.
1999: There is a project underway to reorganize, expand, and update the
sci.crypt FAQ, pending the resolution of some minor legal issues. The
new FAQ will have two pieces. The first piece will be a series of web
pages. The second piece will be a short posting, focusing on the
questions that really are frequently asked.
In the meantime, if you need to know something that isn't covered in the
current FAQ, you can probably find it starting from Ron Rivest's links
at <http://theory.lcs.mit.edu/~rivest/crypto-security.html>.
If you have comments on the current FAQ, please post them to sci.crypt
under the subject line Crypt FAQ Comments. (The crypt-comments email
address is out of date.)
Table of Contents
=================
1. Overview
2. Net Etiquette
2.1. What groups are around? What's a FAQ? Who am I? Why am I here?
2.2. Do political discussions belong in sci.crypt?
2.3. How do I present a new encryption scheme in sci.crypt?
3. Basic Cryptology
3.1. What is cryptology? Cryptography? Plaintext? Ciphertext? Encryption? Key?
3.2. What references can I start with to learn cryptology?
3.3. How does one go about cryptanalysis?
3.4. What is a brute-force search and what is its cryptographic relevance?
3.5. What are some properties satisfied by every strong cryptosystem?
3.6. If a cryptosystem is theoretically unbreakable, then is it
guaranteed analysis-proof in practice?
3.7. Why are many people still using cryptosystems that are
relatively easy to break?
3.8. What are the basic types of cryptanalytic `attacks'?
4. Mathematical Cryptology
4.1. In mathematical terms, what is a private-key cryptosystem?
4.2. What is an attack?
4.3. What's the advantage of formulating all this mathematically?
4.4. Why is the one-time pad secure?
4.5. What's a ciphertext-only attack?
4.6. What's a known-plaintext attack?
4.7. What's a chosen-plaintext attack?
4.8. In mathematical terms, what can you say about brute-force attacks?
4.9. What's a key-guessing attack? What's entropy?
5. Product Ciphers
5.1. What is a product cipher?
5.2. What makes a product cipher secure?
5.3. What are some group-theoretic properties of product ciphers?
5.4. What can be proven about the security of a product cipher?
5.5. How are block ciphers used to encrypt data longer than the block size?
5.6. Can symmetric block ciphers be used for message authentication?
5.7. What exactly is DES?
5.8. What is triple DES?
5.9. What is differential cryptanalysis?
5.10. How was NSA involved in the design of DES?
5.11. Is DES available in software?
5.12. Is DES available in hardware?
5.13. Can DES be used to protect classified information?
5.14. What are ECB, CBC, CFB, and OFB encryption?
6. Public-Key Cryptography
6.1. What is public-key cryptography?
6.2. How does public-key cryptography solve cryptography's Catch-22?
6.3. What is the role of the `trapdoor function' in public key schemes?
6.4. What is the role of the `session key' in public key schemes?
6.5. What's RSA?
6.6. Is RSA secure?
6.7. What's the difference between the RSA and Diffie-Hellman schemes?
6.8. What is `authentication' and the `key distribution problem'?
6.9. How fast can people factor numbers?
6.10. What about other public-key cryptosystems?
6.11. What is the `RSA Factoring Challenge?'
7. Digital Signatures
7.1. What is a one-way hash function?
7.2. What is the difference between public, private, secret, shared, etc.?
7.3. What are MD4 and MD5?
7.4. What is Snefru?
8. Technical Miscellany
8.1. How do I recover from lost passwords in WordPerfect?
8.2. How do I break a Vigenere (repeated-key) cipher?
8.3. How do I send encrypted mail under UNIX? [PGP, RIPEM, PEM, ...]
8.4. Is the UNIX crypt command secure?
8.5. How do I use compression with encryption?
8.6. Is there an unbreakable cipher?
8.7. What does ``random'' mean in cryptography?
8.8. What is the unicity point (a.k.a. unicity distance)?
8.9. What is key management and why is it important?
8.10. Can I use pseudo-random or chaotic numbers as a key stream?
8.11. What is the correct frequency list for English letters?
8.12. What is the Enigma?
8.13. How do I shuffle cards?
8.14. Can I foil S/W pirates by encrypting my CD-ROM?
8.15. Can you do automatic cryptanalysis of simple ciphers?
8.16. What is the coding system used by VCR+?
9. Other Miscellany
9.1. What is the National Security Agency (NSA)?
9.2. What are the US export regulations?
9.3. What is TEMPEST?
9.4. What are the Beale Ciphers, and are they a hoax?
9.5. What is the American Cryptogram Association, and how do I get in touch?
9.6. Is RSA patented?
9.7. What about the Voynich manuscript?
10. References
10.1. Books on history and classical methods
10.2. Books on modern methods
10.3. Survey articles
10.4. Reference articles
10.5. Journals, conference proceedings
10.6. Other
10.7. How may one obtain copies of FIPS and ANSI standards cited herein?
10.8. Electronic sources
10.9. RFCs (available from [FTPRF])
10.10. Related newsgroups
------------------------------
Crossposted-To: talk.politics.crypto,sci.answers,news.answers,talk.answers
Subject: Cryptography FAQ (02/10: Net Etiquette)
From: [EMAIL PROTECTED]
Reply-To: [EMAIL PROTECTED]
Date: 11 Aug 2000 08:44:19 GMT
Archive-name: cryptography-faq/part02
Last-modified: 94/06/13
This is the second of ten parts of the sci.crypt FAQ. The parts are
mostly independent, but you should read the first part before the rest.
We don't have the time to send out missing parts by mail, so don't ask.
Notes such as ``[KAH67]'' refer to the reference list in the last part.
The sections of this FAQ are available via anonymous FTP to rtfm.mit.edu
as /pub/usenet/news.answers/cryptography-faq/part[xx]. The Cryptography
FAQ is posted to the newsgroups sci.crypt, talk.politics.crypto,
sci.answers, and news.answers every 21 days.
Contents:
2.1. What groups are around? What's a FAQ? Who am I? Why am I here?
2.2. Do political discussions belong in sci.crypt?
2.3. How do I present a new encryption scheme in sci.crypt?
2.1. What groups are around? What's a FAQ? Who am I? Why am I here?
Read news.announce.newusers and news.answers for a few weeks. Always
make sure to read a newsgroup for some time before you post to it.
You'll be amazed how often the same question can be asked in the same
newsgroup. After a month you'll have a much better sense of what the
readers want to see.
2.2. Do political discussions belong in sci.crypt?
No. In fact some newsgroups (notably misc.legal.computing) were
created exactly so that political questions like ``Should RSA be
patented?'' don't get in the way of technical discussions. Many
sci.crypt readers also read misc.legal.computing, comp.org.eff.talk,
comp.patents, sci.math, comp.compression, talk.politics.crypto,
et al.; for the benefit of people who don't care about those other
topics, try to put your postings in the right group.
Questions about microfilm and smuggling and other non-cryptographic
``spy stuff'' don't belong in sci.crypt either.
2.3. How do I present a new encryption scheme in sci.crypt?
``I just came up with this neat method of encryption. Here's some
ciphertext: FHDSIJOYW^&%$*#@OGBUJHKFSYUIRE. Is it strong?'' Without a
doubt questions like this are the most annoying traffic on sci.crypt.
If you have come up with an encryption scheme, providing some
ciphertext from it is not adequate. Nobody has ever been impressed by
random gibberish. Any new algorithm should be secure even if the
opponent knows the full algorithm (including how any message key is
distributed) and only the private key is kept secret. There are some
systematic and unsystematic ways to take reasonably long ciphertexts
and decrypt them even without prior knowledge of the algorithm, but
this is a time-consuming and possibly fruitless exercise which most
sci.crypt readers won't bother with.
So what do you do if you have a new encryption scheme? First of all,
find out if it's really new. Look through this FAQ for references and
related methods. Familiarize yourself with the literature and the
introductory textbooks.
When you can appreciate how your cryptosystem fits into the world at
large, try to break it yourself! You shouldn't waste the time of tens
of thousands of readers asking a question which you could have easily
answered on your own.
If you really think your system is secure, and you want to get some
reassurance from experts, you might try posting full details of your
system, including working code and a solid theoretical explanation, to
sci.crypt. (Keep in mind that the export of cryptography is regulated
in some areas.)
If you're lucky an expert might take some interest in what you posted.
You can encourage this by offering cash rewards---for instance, noted
cryptographer Ralph Merkle is offering $1000 to anyone who can break
Snefru-4---but there are no guarantees. If you don't have enough
experience, then most likely any experts who look at your system will
be able to find a flaw. If this happens, it's your responsibility to
consider the flaw and learn from it, rather than just add one more
layer of complication and come back for another round.
A different way to get your cryptosystem reviewed is to have the NSA
look at it. A full discussion of this procedure is outside the scope
of this FAQ.
Among professionals, a common rule of thumb is that if you want to
design a cryptosystem, you have to have experience as a cryptanalyst.
------------------------------
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