Cryptography-Digest Digest #150, Volume #11 Fri, 18 Feb 00 11:13:01 EST
Contents:
Re: UK publishes 'impossible' decryption law (Gordon Walker)
Re: Does the NSA have ALL Possible PGP keys? (Johnny Bravo)
Re: Which compression is best? (SCOTT19U.ZIP_GUY)
Re: Does the NSA have ALL Possible PGP keys? (Johnny Bravo)
Re: OAP-L3 Encryption Software - Complete Help Files at web site (Anthony Stephen
Szopa)
Re: OAP-L3 Encryption Software - Complete Help Files at web site (Anthony Stephen
Szopa)
Basic Crypto Question 4 ([EMAIL PROTECTED])
Re: EOF in cipher??? ("Trevor Jackson, III")
Re: EOF in cipher??? ("Trevor Jackson, III")
Re: EOF in cipher??? ("Trevor Jackson, III")
Re: Does the NSA have ALL Possible PGP keys? ("Trevor Jackson, III")
Re: Does the NSA have ALL Possible PGP keys? ("Trevor Jackson, III")
Re: UK publishes 'impossible' decryption law ("Scotty")
Re: Processor speeds. ("Matt Sottile")
Re: Does the NSA have ALL Possible PGP keys? ("Trevor Jackson, III")
Re: Have you watched the movie "PI" (actually a mathematical symbol PI) (Bacteria
Joe)
Re: Processor speeds. (John)
Re: OAP-L3 Encryption Software - Complete Help Files at web site (Tony L. Svanstrom)
Re: EOF in cipher??? (Runu Knips)
Re: EOF in cipher??? (Runu Knips)
Re: Does the NSA have ALL Possible PGP keys? (John Myre)
Re: EOF in cipher??? (Runu Knips)
----------------------------------------------------------------------------
From: [EMAIL PROTECTED] (Gordon Walker)
Crossposted-To: talk.politics.crypto
Subject: Re: UK publishes 'impossible' decryption law
Date: Fri, 18 Feb 2000 14:15:06 GMT
On Fri, 18 Feb 2000 11:16:17 +0100, "ink" <[EMAIL PROTECTED]>
wrote:
>>Any firearm can be used as a weapon. The US govt considers crypto to be
>dangerous
>>
>>enough that it is classified as a "munition". What does that tell you?
>
>Hardly any other government has doen that. What does that tell you?
Many western governments (UK, France etc) have restricted cryptography
in some way. I neither know nor care whether they implemented these
restrictions by such a classification.
--
Gordon Walker
------------------------------
From: Johnny Bravo <[EMAIL PROTECTED]>
Crossposted-To: misc.survivalism
Subject: Re: Does the NSA have ALL Possible PGP keys?
Date: Fri, 18 Feb 2000 09:23:57 +0000
On Fri, 18 Feb 2000 01:53:32 -0800, "tiwolf" <[EMAIL PROTECTED]> wrote:
>My ability to think is clear, there is nothing impossible
You are confusing physical impossibility with logical impossibility. If
you want to persist in this nonsense answer one question.
"Can God create a rock so heavy he can't lift it?"
If "Yes", then he is not all powerful as he can't lift the rock.
If "No", then he is not all powerful as he can't create the rock.
So, answer the question, Can God do it, Yes or No?
>While those here claim that it can't be done I say that if it has not
>yet been done it will be done eventually.
You have shown a profound lack of critical thinking ability, what "you
say" has very little bearing on the topic under discussion.
>Other argue the philosophy that God does not know the highest form of pi or
>even that there is an end to pi for God to know.
Quite so, you cannot assign a value to an infinite number. If you
assign a value you are claiming that the number is not infinite.
>I argue that God inspires innovation and thought therefore,
You can argue all you want, completely pointless without any proof.
>God knows all of pi string.
We can calculate any digit we want, and if we had an infinite time to
work we could produce an infinite number of digits, but not even God can
tell you the last one. You just don't have the education needed to
realize that God can't tell you something that can't exist.
>If God was willing he could tell us the whole string, we would
>die before he finished speaking but God would still be telling
>our corpses the pi string.
No, he can't. If so he could tell us the last digit first, without
waiting for us to die. Your entire argument is that pi has a last digit,
you lack of understanding is legion.
>We are finite, God is infinite.
Pi is infinite too, you seem to have some serious trouble grasping the
concept of infinity. No doubt it explains the trouble you are having in
quantifying your "God".
--
Best Wishes,
Johnny Bravo
"The most merciful thing in the world, I think, is the inability
of the human mind to correlate all it's contents." - HPL
------------------------------
From: [EMAIL PROTECTED] (SCOTT19U.ZIP_GUY)
Subject: Re: Which compression is best?
Date: Fri, 18 Feb 2000 15:11:45 GMT
In article <[EMAIL PROTECTED]>, Runu Knips
<[EMAIL PROTECTED]> wrote:
>Tim Tyler schrieb:
>> Runu Knips <[EMAIL PROTECTED]> wrote:
>> : This is how ALL compressors work. No matter if simple RLE or
>> : Huffman or ZiffDavis or whatever. Their output always follows rules.
>> Their "output always follows rules" in the sense that it is
>> deterministically derived from the input text.
>> : [...]
>> That does *not* mean you can write a program that identifies compressed
>> files as such.
>
>Well okay, I in fact didn't tried this in practice. For example, I know
>that Huffman has to first dump the huffman tree, and then the huffman
>codes follow. And because the input is not ideal random data (where each
>character appears as often as the other), you will not get a balanced
>tree (which would make compression by Huffman impossible anyway) as the
>huffman tree, therefore some codes are not possible.
>
>An easy example is the huffman alphabet for a file which contain 70%
>nuls and 10% space plus 10% A plus 10% B (just to make calculation
>easy). The resulting alphabet would be:
>
>NUL = 0
>SPACE = 100
>A = 101
>B = 110
You obviously have a piss poor understanding of even basic huffman
coding. No wonder your totally lost in the disscussion with Tim. Please
try to learn something about basic huffman coding before you start to
generalize about stuff of which you seem to have no idea.
This example you give above where a file contains only 4 symbols
would not have the tree you show above.
True Null could equal 0
and Space could equal 100
and A could equal 101
but then B would have to be 11
Sorry but I assume if these minor points are over your head
you will not be able to understand Tim
David A. Scott
--
SCOTT19U.ZIP NOW AVAILABLE WORLD WIDE
http://www.jim.com/jamesd/Kong/scott19u.zip
Scott famous encryption website NOT FOR WIMPS
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
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: Johnny Bravo <[EMAIL PROTECTED]>
Crossposted-To: misc.survivalism
Subject: Re: Does the NSA have ALL Possible PGP keys?
Date: Fri, 18 Feb 2000 09:27:43 +0000
On Thu, 17 Feb 2000 22:24:47 -0500, "Trevor Jackson, III"
<[EMAIL PROTECTED]> wrote:
>Ah, but can he create a rock that he cannot lift? (The classic answer is no --
>he would not).
I was trying to avoid doing that to him, probably overload his religious
programming. I had no choice, he pushed me to it, I swear. :)
His trouble is that some things are just created concepts that are not
logical. "What hair color is bald?" for example, asking you to equate a
member of a set to the null set. :) Much like "What is the last digit of
pi?", or "What is the biggest integer?", just can't be done.
--
Best Wishes,
Johnny Bravo
"The most merciful thing in the world, I think, is the inability
of the human mind to correlate all it's contents." - HPL
------------------------------
From: Anthony Stephen Szopa <[EMAIL PROTECTED]>
Crossposted-To: talk.politics.crypto,alt.privacy
Subject: Re: OAP-L3 Encryption Software - Complete Help Files at web site
Date: Fri, 18 Feb 2000 06:38:26 -0800
"Tony L. Svanstrom" wrote:
>
> Anthony Stephen Szopa <[EMAIL PROTECTED]> wrote:
>
> > Otherwise we will just have to consider you unprofessional,
> > irresponsible, ignorant, and possibly stupid.
> >
> > This goes for the rest of you superficial critics, also.
>
> What will we see next, that "after testing our claims among the best of
> the Internet no serious cryptographer has anything bad to say about our
> software"? Which you are saying simply because you label everyone that
> has anything bad to say as "unprofessional, irresponsible, ignorant, and
> possibly stupid [...] superficial critics"?
>
> /Tony
> --
> /\___/\ Who would you like to read your messages today? /\___/\
> \_@ @_/ Protect your privacy: <http://www.pgpi.com/> \_@ @_/
> --oOO-(_)-OOo---------------------------------------------oOO-(_)-OOo--
> DSS: 0x9363F1DB, Fp: 6EA2 618F 6D21 91D3 2D82 78A6 647F F247 9363 F1DB
> ---���---���-----------------------------------------------���---���---
> \O/ \O/ �1999 <http://www.svanstrom.com/?ref=news> \O/ \O/
None of you have convinced anyone of anything and the reason this is
so is simply because none you have made any legitimate claim to support
your strong position that OAP-L3 is "garbage."
You all offer nothing but excuses.
There can only be one reason: you cannot do so.
------------------------------
From: Anthony Stephen Szopa <[EMAIL PROTECTED]>
Crossposted-To: talk.politics.crypto,alt.privacy
Subject: Re: OAP-L3 Encryption Software - Complete Help Files at web site
Date: Fri, 18 Feb 2000 06:45:27 -0800
ink wrote:
>
> Anthony Stephen Szopa schrieb in Nachricht ...
> >All right, Emeritus Fool.
>
> Keep cool. Please.
>
> >A musical score can be precisely described mathematically yet it came into
> >being from the creative mind of a composer. Or are you claiming that a
> >composer used a mathematical equation to compose the music?
>
> I think that can hardly be compared. Stick to the topic, okay?
>
> >Why are people using OAP-L3 encryption software with no complaints?
> Because
> >they are more than satisfied: that's why.
>
> IMHO that might also be because no-one tried to attack OAP-L3 so far. Or
> have there been serious attacks that the system would withstand? Please
> inform us about that. No need to get all worked up.
>
> Kind regards,
>
> Kurt
>
> �Intelligence is when you spot the flaw in your boss�s
> reasoning. Wisdom is when you refrain from pointing
> it out.� - James Dent
Before anyone can execute an attack against the OAP-L3 encryption
software, they must first make a plan of attack.
The entire Help files included with OAP-L3 are available at the web
site: http://www.ciphile.com
Considering the theory and operation of OAP-L3, we would first like
to hear any reasonable SUGGESTION where one might start their attack,
with supporting arguments as to why their proposed attack might
get results.
------------------------------
From: [EMAIL PROTECTED]
Subject: Basic Crypto Question 4
Date: Fri, 18 Feb 2000 14:57:28 GMT
Has Elliptic Curve Crypto Come of Age?
Will it now play a significant role in Public key crypto, especially in
the emerging wireless market with the advantage of shorter key length
(160 ECC eq to 1024 RSA), and faster speeds.
Is EEC mature enough as a technology to emerge and take a sizable chunck
of the crypto market?
Certicom is the main contender for ECC Crypto, now they have even
released a PKI Toolkit based on ECC.
There are also some Free ECC Crypto Libraries. How do they compare with
the Certicom ECC API?
For Wireless it seems the choice between ECC and RSA/DH is clear...ECC
wins all the way.
The NIST has even included a Digital Standard based on ECC....
Sent via Deja.com http://www.deja.com/
Before you buy.
------------------------------
Date: Fri, 18 Feb 2000 10:26:44 -0500
From: "Trevor Jackson, III" <[EMAIL PROTECTED]>
Subject: Re: EOF in cipher???
"Douglas A. Gwyn" wrote:
> "Trevor Jackson, III" wrote:
> > Mok-Kong Shen wrote:
> > > I am ignorant of what the C standard specifies. Question: Does
> > > 'binary' require the file to be multiple of words or just any multiple
> > > of bytes will do? Thanks.
> > Neither. The elements written to files are characters. Sometimes
> > (usually) that means bytes.
>
> Wrong. Bytes are written to binary files, characters to text files.
Interesting. Tell me, just how do they do that on a machine that doesn't
_have_ bytes?
Don't go so far out of your way to "correct" me that you end up asserting
something completely stupid.
------------------------------
Date: Fri, 18 Feb 2000 10:28:00 -0500
From: "Trevor Jackson, III" <[EMAIL PROTECTED]>
Subject: Re: EOF in cipher???
Mok-Kong Shen wrote:
> Douglas A. Gwyn wrote:
> >
>
> > The basic C standard I/O functions such as getc/putc operate on
> > bytes, always; when the stream was opened as a text stream, there
> > is (on many non-POSIX systems) additional mapping between the
> > program internal data and external data. For example, newline
> > pseudo-characters are introduced between text records in a fixed-
> > record format environment, or for MS-DOS, CR,LF pairs are replaced
> > by a single NL internally, and ^Z might be interpreted as ending
> > the text stream (which was the cause of this thread). No such
> > mapping is performed when the file was opened as a binary stream.
>
> To be sure that I didn't misunderstand, I like to ask whether the
> code (from KR):
>
> while ((C = getc(fp)) != EOF)
> .........
>
> needs to be modified or using rb is sufficient for taking care of
> the presence of any bit combinations in the file. Thanks.
>
The issue is the type of the variable C. To operate correctly it must
be an int not a char.
------------------------------
Date: Fri, 18 Feb 2000 10:43:11 -0500
From: "Trevor Jackson, III" <[EMAIL PROTECTED]>
Subject: Re: EOF in cipher???
"Douglas A. Gwyn" wrote:
> "Trevor Jackson, III" wrote:
> > Runu Knips wrote:
> > > EOF works well, because EOF is defined to be -1, while all characters
> > > are returned as nonnegative values.
> > This is _completely_ off topic. But the last statement is completely
> > false. The signedness of characters is implementation defined. Thus on
> > some systems characters are signed.
>
> No, first of all you mean char type, not characters.
> Secondly, the standard I/O functions such as getc deal with
> the data as unsigned char. So long as sizeof(char) < sizeof(int),
> which is practically always the case, EOF (-1) can never result
> from inputting any data value, even when char is a signed type.
>
> Please stop giving bad C advice!
You are out of line again. The original statement was that "all characters
are returned as nonnegative values". That statement was false.
And there are machines where EOf != -1 and some where sizeof(char) ==
sizeof(int). I've worked on them.
If you are advising programmers to make invalid and unnecessary assumptions
about the architecture of their machines, which of us is giving "bad C
advice".
------------------------------
Date: Fri, 18 Feb 2000 10:49:47 -0500
From: "Trevor Jackson, III" <[EMAIL PROTECTED]>
Crossposted-To: misc.survivalism
Subject: Re: Does the NSA have ALL Possible PGP keys?
Clearly we have different referents for the term "think".
tiwolf wrote:
> My ability to think is clear, there is nothing impossible only tasks which
> we are not yet equipped to perform. While those here claim that it can't be
> done I say that if it has not yet been done it will be done eventually.
> Other argue the philosophy that God does not know the highest form of pi or
> even that there is an end to pi for God to know. Since that is the argument,
> I argue that God inspires innovation and thought therefore, God knows all of
> pi string. If God was willing he could tell us the whole string, we would
> die before he finished speaking but God would still be telling our corpses
> the pi string. We are finite, God is infinite.
>
> Trevor Jackson, III wrote in message <[EMAIL PROTECTED]>...
> >tiwolf wrote:
> >
> >> Now Johnny who is blatant stupidity, you claim that even God does not
> know
> >> what the highest number is. Given that God is created all things in the
> >> universe, and inspired human creativity and invention, how can you say
> that
> >> God does not know what the highest number is. That would be an indication
> of
> >> limit and according to the philosophical debate and my religious up
> bringing
> >> God is limitless in power and knowledge.
> >
> >The true issue appears at last. Your upbringing is interfering with your
> >ability to think. It's a reasonably popular excuse these days.
> >
> >
------------------------------
Date: Fri, 18 Feb 2000 10:53:45 -0500
From: "Trevor Jackson, III" <[EMAIL PROTECTED]>
Crossposted-To: misc.survivalism
Subject: Re: Does the NSA have ALL Possible PGP keys?
"Douglas A. Gwyn" wrote:
> "Trevor Jackson, III" wrote:
> > Ah, but can he create a rock that he cannot lift?
>
> Basically, the question is whether a contradiction can exist.
> If you take the position that it cannot (which is fundamental
> to effective thought), then it is easy to show that there is
> a problem with the definition of X as something that has no
> restrictions.
Yes.
This is the essential issue. Terms of universality, e.g. "never",
"every", "all", "none", are danger signs.
> Non-contradiction *is* a restriction; thus the
> conclusion is that X as described must not exist. For some
> people, this comes down to choosing between belief in an
> all-powerful God versus a non-contradictory universe. (Others
> manage to avoid making the choice, in which case they have
> implicitly chosen the former.)
------------------------------
From: "Scotty" <[EMAIL PROTECTED]>
Crossposted-To: talk.politics.crypto
Subject: Re: UK publishes 'impossible' decryption law
Date: Fri, 18 Feb 2000 15:51:20 -0000
Gordon Walker wrote in message <[EMAIL PROTECTED]>...
>On Fri, 18 Feb 2000 11:16:17 +0100, "ink" <[EMAIL PROTECTED]>
>wrote:
>
>>>Any firearm can be used as a weapon. The US govt considers crypto to be
>>dangerous
>>>
>>>enough that it is classified as a "munition". What does that tell you?
>>
>>Hardly any other government has doen that. What does that tell you?
>
>Many western governments (UK, France etc) have restricted cryptography
>in some way. I neither know nor care whether they implemented these
>restrictions by such a classification.
BTW France was very restricted, until a short while ago, when the whole law
was reversed, so that now France is much freer than the UK.
------------------------------
From: "Matt Sottile" <[EMAIL PROTECTED]>
Subject: Re: Processor speeds.
Date: Fri, 18 Feb 2000 15:47:33 GMT
> John wrote:
> >
> > How many MIPS does a pentium 3 perform? How many does the
> > fastest super computer perform?
MIPS, FLOPS, Mhz aren't really good for comparing between machines. A
machine may have "better" performance on a certain type of job even though
another machine has a "better" MIPS rating. (Example: vector processor VS
superscalar processor on matrix operations). To answer your question
regarding the average PC chip vs the big computers, the average 2 350Mhz PII
machine can achieve somewhere beterrn 80 and 150 MFlops (Megaflops ==
millions of floating point operations per second, sometimes written
"MegaOps"). The current leading machine for open (unclassified) computation
is ACL Nirvana at Los Alamos, and that machine can to somewhere around 1
Teraflop (1 Trillion FLOPS or OPS). The classified machines are even
faster. :)
==> Matt Sottile
==> http://www.cs.uoregon.edu/~matt/
------------------------------
Date: Fri, 18 Feb 2000 10:56:59 -0500
From: "Trevor Jackson, III" <[EMAIL PROTECTED]>
Crossposted-To: misc.survivalism
Subject: Re: Does the NSA have ALL Possible PGP keys?
Johnny Bravo wrote:
> On Thu, 17 Feb 2000 22:24:47 -0500, "Trevor Jackson, III"
> <[EMAIL PROTECTED]> wrote:
>
> >Ah, but can he create a rock that he cannot lift? (The classic answer is no --
> >he would not).
>
> I was trying to avoid doing that to him, probably overload his religious
> programming. I had no choice, he pushed me to it, I swear. :)
Looks like three of rout of us came up with the same classic challenge. It's a
classic because it is so useful in highlighting the contradictory nature of
infinitude.
>
>
> His trouble is that some things are just created concepts that are not
> logical. "What hair color is bald?" for example, asking you to equate a
> member of a set to the null set. :) Much like "What is the last digit of
> pi?", or "What is the biggest integer?", just can't be done.
Well, some of these issues have real, practical implications. Like where does your
lap go when you stand up.
My cat would really like to know. ;-)
------------------------------
From: Bacteria Joe <[EMAIL PROTECTED]>
Crossposted-To:
alt.politics.org.cia,soc.culture.russian,soc.culture.israel,alt.math,alt.2600
Subject: Re: Have you watched the movie "PI" (actually a mathematical symbol PI)
Date: Fri, 18 Feb 2000 10:56:57 -0500
Androcles wrote:
>
> aslan <[EMAIL PROTECTED]> wrote in message
> news:8814tf$[EMAIL PROTECTED]...
> > .... a real movie?! ....
> >
> > jesus i haven't seen a REAL movie since the crazy things were invented!
>
> Gosh darn it! I was gonna say that but you beat me to it. :-)
> Androcles
I was gonna say a Reel movie instead,
but that would just be WAAaaaaayyyyy
off topic.
So...
where can I get some porn?
Bacteria Joe
------------------------------
Subject: Re: Processor speeds.
From: John <[EMAIL PROTECTED]>
Date: Fri, 18 Feb 2000 07:52:14 -0800
Thanks. Very well thought out answer. It reminds md of my old
college days in CS. Anyways, it did help. The processor speed
MHZ (I suspected) was the key. I guess I wanted a rough
estimate of how much faster the best home PC is as compared to
the latest "super-computer." I know that the gap is closing.
http://www.aasp.net/~speechfb
* Sent from RemarQ http://www.remarq.com The Internet's Discussion Network *
The fastest and easiest way to search and participate in Usenet - Free!
------------------------------
From: [EMAIL PROTECTED] (Tony L. Svanstrom)
Crossposted-To: talk.politics.crypto,alt.privacy
Subject: Re: OAP-L3 Encryption Software - Complete Help Files at web site
Date: Fri, 18 Feb 2000 17:00:14 +0100
Anthony Stephen Szopa <[EMAIL PROTECTED]> wrote:
> None of you have convinced anyone of anything and the reason this is
> so is simply because none you have made any legitimate claim to support
> your strong position that OAP-L3 is "garbage."
>
> You all offer nothing but excuses.
>
> There can only be one reason: you cannot do so.
No, there could be lots of reasons... One might be that we're too busy
making fun of you and your stupid claims...
Just look at that stupid Money-Back Guarantee, if I buy your program I
have only 180 days to prove that it's useless, and then I'll only get my
money back... Meaning that you don't trust your program more than 10
bucks worth. That's nice to know, if I lose 10'000+ USD because I
trusted your "practicably unbreakable" software I will get 10 USD back
(but only if it happens within 180 days after I got the software).
/Tony
--
/\___/\ Who would you like to read your messages today? /\___/\
\_@ @_/ Protect your privacy: <http://www.pgpi.com/> \_@ @_/
--oOO-(_)-OOo---------------------------------------------oOO-(_)-OOo--
DSS: 0x9363F1DB, Fp: 6EA2 618F 6D21 91D3 2D82 78A6 647F F247 9363 F1DB
---���---���-----------------------------------------------���---���---
\O/ \O/ �1999 <http://www.svanstrom.com/?ref=news> \O/ \O/
------------------------------
Date: Fri, 18 Feb 2000 16:55:32 +0100
From: Runu Knips <[EMAIL PROTECTED]>
Subject: Re: EOF in cipher???
"Trevor Jackson, III" schrieb:
>
> Runu Knips wrote:
>
> > JPeschel schrieb:
> > >
> > > "Douglas A. Gwyn" writes:
> > >
> > > >When reading random bit patterns, the program should not perform any
> > > >text format interpretations. In C, the file should be opened as a
> > > >binary stream, not a text stream.
> > >
> > > And use FEOF to detect the end of the binary file being read.
> >
> > FEOF is not standard. Which compiler defines such a strange variable ?
> > EOF works well, because EOF is defined to be -1, while all characters
> > are returned as nonnegative values.
>
> This is _completely_ off topic. But the last statement is completely
> false. The signedness of characters is implementation defined. Thus on
> some systems characters are signed.
Correct. But getc() returns int, and the standard states that the
value returned is the value of the _UNSIGNED_ character, i.e. the
value returned by getc() is always non-negative, except if EOF
is reached.
------------------------------
Date: Fri, 18 Feb 2000 16:59:58 +0100
From: Runu Knips <[EMAIL PROTECTED]>
Subject: Re: EOF in cipher???
"Trevor Jackson, III" schrieb:
>
> "Douglas A. Gwyn" wrote:
>
> > "Trevor Jackson, III" wrote:
> > > Runu Knips wrote:
> > > > EOF works well, because EOF is defined to be -1, while all characters
> > > > are returned as nonnegative values.
> > > This is _completely_ off topic. But the last statement is completely
> > > false. The signedness of characters is implementation defined. Thus on
> > > some systems characters are signed.
> >
> > No, first of all you mean char type, not characters.
> > Secondly, the standard I/O functions such as getc deal with
> > the data as unsigned char. So long as sizeof(char) < sizeof(int),
> > which is practically always the case, EOF (-1) can never result
> > from inputting any data value, even when char is a signed type.
> >
> > Please stop giving bad C advice!
>
> You are out of line again. The original statement was that "all characters
> are returned as nonnegative values". That statement was false.
That statement is true. Its exactly what the standard says.
> And there are machines where EOf != -1 and some where sizeof(char) ==
> sizeof(int). I've worked on them.
Thats both against the standard. ISO specifies that int must be at least
16 bit (i.e. it says short must be 16 bit, and sizeof(int) >=
sizeof(short),
which means int is also at least 16 bit). A character value, however, is
the smallest type which has at least 7 bit.
> If you are advising programmers to make invalid and unnecessary assumptions
> about the architecture of their machines, which of us is giving "bad C
> advice".
I'm sorry, but thats all from my good old K&R book (the version which
was
published after ISO and already contained the changes).
------------------------------
From: John Myre <[EMAIL PROTECTED]>
Subject: Re: Does the NSA have ALL Possible PGP keys?
Date: Fri, 18 Feb 2000 08:55:32 -0700
Paul Crowley wrote:
>
<snip>
> A curious thing I've noticed: there aren't very many problems left in
> NP that haven't been classified either as P or as NP-complete,
> according to my complexity lecturer. But the ones there are keep
> being useful in crypto! Examples include graph isomorphism (thought
> to be in P unfortunately) and, of course, factorisation. What's the
> good property these problems have that no NP-complete problem has?
> Why is this property incompatible with NP-completeness?
Of course I really have no clue, but how about this: the useful
property is really only ignorance.
That is, the problems about which we understand enough to
classify their difficulty well, are the problems we know how
to finesse when used for crypto.
I hope this is a wrong guess...
John M.
P.S.
In all seriousness, algorithm complexity and cryptographic
security have a fundamental difference. Complexity is
measured in the worst case (what is the longest time it
might take to solve a problem), while security hinges on the
best case (what is the least time it might take). It might
be that the concepts are almost unrelated.
------------------------------
Date: Fri, 18 Feb 2000 17:05:53 +0100
From: Runu Knips <[EMAIL PROTECTED]>
Subject: Re: EOF in cipher???
"Trevor Jackson, III" schrieb:
> Mok-Kong Shen wrote:
> > To be sure that I didn't misunderstand, I like to ask whether the
> > code (from KR):
> > while ((C = getc(fp)) != EOF)
> > .........
> > needs to be modified or using rb is sufficient for taking care of
> > the presence of any bit combinations in the file. Thanks.
> The issue is the type of the variable C. To operate correctly it must
> be an int not a char.
Unfortunately, the above code will run on many systems without
problems until fp is a binary file which happends to contain
the code 0xff, which is equal to (signed char)-1 (on machines
with 8 bits for a character).
------------------------------
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