Juergen Nieveler
Guest
Posts: n/a

 12-02-2005
"nemo_outis" <(E-Mail Removed)> wrote:

> If you would not notice somebody looking (or other forms of
> surrepitious observation and/or recording) there is something
> desperately wrong, either with you or with your environment.

tempest-shielded?

Juergen Nieveler
--
I don't like abuse, but I'm very good at it

TwistyCreek
Guest
Posts: n/a

 12-02-2005
nemo_outis wrote:

> Borked Pseudo Mailed <(E-Mail Removed)> wrote in
> news:(E-Mail Removed) d.net:
>
>
> Yawn! You have now exhausted what little entertainment value you
> provided. And so.... PLONK!

Mightymouth nemo outhouse at a complete loss for words....... and
announcing a plonk like some clueless noob!!

BWA HA HA HA HA HA HA HA HA HA HA!!!

jKILLSPAM.schipper@math.uu.nl
Guest
Posts: n/a

 12-02-2005
AV <(E-Mail Removed)> wrote:
> That sounds very strange to me since the first one has so many more
> characters and has misspelled words.

That does not, per se, mean the encryption is stronger. After all,
'booooooooooring' is not a very strong password...

Let's throw some math at it.

Each word is chosen from a vocabulary of, say, 10000 words (this
includes weird words very few people will know - the active vocabulary
of the average English speaker is ~ 5000 words, IIRC - though that seems
very small) and has 100 different 'correct' ways of spelling it. Then,
six random words with random misspellings have an entropy of
(10000*100)^6 = (10^7)^6 = 10^56 > (2^3)^59 = 2^171.
(If only common words - 1000 total - are used, this will be about
(10^6)^6 = 10^36 > (2^3)^36 = 2^108.)

The second one has eight characters, chosen from a-z, A-Z, 0-9, and
say ten miscellaneous characters, if done right. That would mean 40^8,
or about (2^5)^8 = 2^40 options. Quite a bit worse than the first one.

This does assume that people are not allowed to pick the password in
either case (i.e., it's true random or as close to that as you can get),
*and* the words in the first case *don't form a sentence* (as yours do).
If they do, entropy decreases dramatically; I have heard it say that
entropy decreases to only a few paltry bits (10000 is about 13 bits;
I've heard as low as 1.2 bits for phrases), and entropy may drop as low
as (2 * 100)^6 > (2^7)^6 = 2^42.

It also assumes that one is more creative in misspelling than you did in
per character, and many words are rather small (so 100 will be a little
high - and if using both phrases, with at worst 1 bit of entropy per
word, and simple misspellings with about 4 bits of entropy per word, we
have a key space of only (2^1 * 2^4)^6 = 2^30, in which case the simpler
passwords appear to be more attractive).

In short, calculating the entropy for the first one isn't
straightforward, but seems to suggest that unless lots of randomization
is involved, it is rather weak. Especially if humans are allowed to pick
the phrase.

(Note: it also assumes that the whole password is required - some
mechanisms use only the first eight characters. Oopsie.)

> And shouldn't any secure login to anything only accept just a few
> attempts, e.g. three.

Theoretically, yes. Practically, such 'protection' almost always opens
the door for an easy DoS, *especially* when the network can be sniffed.

> To me it seems like if you just such a system (or
> application) then actually a rather short password should be rather
> safe. How likely is my "weak" passphrase below will be entered in three
> attempts? And after these three attempts you need to restart the
> application. How long time would it take for the fastest machine on
> earth today to brute force that passphrase?

Not that long, DES is quite crackable and has 2^56 bits in its key,
IIRC.

And 'only three attempts' doesn't work all that well in the real world.

> But again, I cannot understand that the first one is considered weaker
> than the second one. In TrueCrypt it is the opposite. You get a warning
> if the password/phrase is shorter than 20 characters. I suppose you
> could find other sites that are of opposite opinion?

Well, at least, the number of characters has very little bearing on the
strength of the passphrase...

Joachim

Slight correction
Guest
Posts: n/a

 12-02-2005
In general, I think your reasoning is right, but you didn't spend
enough time on the math.

In Message-ID:<439048a9\$0\$68918\$(E-Mail Removed)>,
http://www.velocityreviews.com/forums/(E-Mail Removed) wrote:

>Then,
>six random words with random misspellings have an entropy of
>(10000*100)^6 = (10^7)^6 = 10^56 > (2^3)^59 = 2^171.

10000*100 = 10^6, not 10^7. (10^6)^6 is between 2^119 and 2^120.

(Also, (10^7)^6 = 10^42, not 10^56. Perhaps you were thinking
ahead to the next example where 8 is the proper exponent, rather
than 6.)

>The second one has eight characters, chosen from a-z, A-Z, 0-9, and
>say ten miscellaneous characters, if done right. That would mean 40^8,
>or about (2^5)^8 = 2^40 options. Quite a bit worse than the first one.

a-z is 26; A-Z is another 26; 0-9 is 10 plus "ten miscellaneous
characters", adds to 72 possible characters. That would mean
72**8 or about 2^49. Still, as you said, much worse than the
above. (Where did your 40 come from?)

>This does assume that people are not allowed to pick the password in
>either case (i.e., it's true random or as close to that as you can get),
>*and* the words in the first case *don't form a sentence* (as yours do).
>If they do, entropy decreases dramatically; I have heard it say that
>entropy decreases to only a few paltry bits (10000 is about 13 bits;
>I've heard as low as 1.2 bits for phrases), and entropy may drop as low
>as (2 * 100)^6 > (2^7)^6 = 2^42.

What I've heard is that English text is about 1.2 to 1.4 bits of
entropy per character. I don't know if that includes the spaces
between words. Even if it does, 6 6-letter words in a phrase
would yield 41 characters or at most just over 57 bits of entropy.

jKILLSPAM.schipper@math.uu.nl
Guest
Posts: n/a

 12-02-2005
Slight correction <(E-Mail Removed)> wrote:
> In general, I think your reasoning is right, but you didn't spend
> enough time on the math.

> 10000*100 = 10^6, not 10^7. (10^6)^6 is between 2^119 and 2^120.
>
> (Also, (10^7)^6 = 10^42, not 10^56. Perhaps you were thinking
> ahead to the next example where 8 is the proper exponent, rather
> than 6.)

> a-z is 26; A-Z is another 26; 0-9 is 10 plus "ten miscellaneous
> characters", adds to 72 possible characters. That would mean
> 72**8 or about 2^49. Still, as you said, much worse than the
> above. (Where did your 40 come from?)

> What I've heard is that English text is about 1.2 to 1.4 bits of
> entropy per character. I don't know if that includes the spaces
> between words. Even if it does, 6 6-letter words in a phrase
> would yield 41 characters or at most just over 57 bits of entropy.

Duh! And I knew all that! That'll teach me not to try math without
writing it out on paper first, taking some time, and not being
distracted.

Oops.

Anyway, given the above theorems the diligent student can easily find

Joachim

nemo_outis
Guest
Posts: n/a

 12-02-2005
Juergen Nieveler <(E-Mail Removed)> wrote in
news:(E-Mail Removed):

> "nemo_outis" <(E-Mail Removed)> wrote:
>
>> If you would not notice somebody looking (or other forms of
>> surrepitious observation and/or recording) there is something
>> desperately wrong, either with you or with your environment.

>
> tempest-shielded?
>
> Juergen Nieveler

Nope, not required as as a result of my risk and threat assessments. Nor
is protection against laser interferometry on windows and a few other
exotic attacks.

However, I have posted on how to tackle threats such as Tempest related
attacks, including my preference for older low-MHz laptops (lesser emsec
concerns, no exposed cables, no need to isolate power supplies, possible to
use RF-shielded enclosures rather than shielded rooms, etc.). Constructing
full room-size high-MHz Faraday cages is a bear - the grounding aspects
alone present significant challenges (as do seals, conduits, air exchange,
etc.)

Despite your gibe, physical security does not mean that one must always
escalate to Fort Knox. No, it means that the level of physical security
should be commensurate with the threats, the risks they pose, and the
consequences of security breaches. However, all but the very lowest levels
of physical security require freedom from direct visual observation by
others.

But you knew that already; it's just fun to tease me

Regards,

Nomen Nescio
Guest
Posts: n/a

 12-02-2005
nemo_outis wrote:

> However, I have posted on how to tackle threats such as Tempest related
> attacks, including my preference for older low-MHz laptops (lesser emsec

There's no such thing as a "tempest related attack". Tempest is an NSA/OSS
security policy (90-6) that encompasses a LOT more than RF emissions.

> concerns, no exposed cables, no need to isolate power supplies, possible
> to use RF-shielded enclosures rather than shielded rooms, etc.).
> Constructing full room-size high-MHz Faraday cages is a bear - the

Actually, Faraday cages are trivial to construct. But then in modern times
they're mostly useless because it's impossible to construct one that's
effective at modern bandwidths, or against things like op-fiber leaks.

> grounding aspects alone present significant challenges (as do seals,
> conduits, air exchange, etc.)
>
> Despite your gibe, physical security does not mean that one must always
> escalate to Fort Knox. No, it means that the level of physical security

No, but it does mean that you don't type your passwords on a screen that
anyone can see from across the room by squinting, or across the street
with a set of binoculars.

> should be commensurate with the threats, the risks they pose, and the

Like letting those asterisk do the job they were designed for rather than
screen? In an environment where that IS your risk assessment and solution?

> consequences of security breaches. However, all but the very lowest
> levels of physical security require freedom from direct visual
> observation by others.
>
> But you knew that already; it's just fun to tease me
>
> Regards,

nemo_outis
Guest
Posts: n/a

 12-02-2005
Nomen Nescio <(E-Mail Removed)> wrote in
news:(E-Mail Removed):

> There's no such thing as a "tempest related attack". Tempest is an
> NSA/OSS security policy (90-6) that encompasses a LOT more than RF
> emissions.

When you raise pointless pedantic quibbles, you should make some effort to
ensure that you have got things right. You haven't!

The word Tempest is widely used, not merely to refer the specifics of the
eponymously codenamed set of classified standards for reducing emissions
from electronic information handling equipment and facilities (the details
of which are NOT public) but more broadly to refer to all matters regarding
emsec, especially computer-related emsec. There are literally tens upon
tens of thousands of entries on Google confirming this. As just one
example, one of the better sites uses the term Tempest much as I do.

The Complete, Unofficial TEMPEST Information Page
http://www.eskimo.com/~joelm/tempest.html

> Actually, Faraday cages are trivial to construct. But then in modern
> times they're mostly useless because it's impossible to construct one
> that's effective at modern bandwidths, or against things like op-fiber
> leaks.

Oh, it's easy to make a Faraday cage, you say - as long as it doesn't
matter whether it works! Now there's a penetrating insight! Do you apply
such high standards to all your undertakings?

On your basis then, I've constructed a time-travel machine from cardboard
and duct-tape. Its only small defect is that it doesn't work.

What a buffoon you are!

Regards,

Thrasher Remailer
Guest
Posts: n/a

 12-03-2005
nemo_outis wrote:

> The word Tempest is widely used, not merely to refer the specifics of the

The word "nigger" is widely used too. That doesn't make it any more
correct to use it to describe black people. Especially when you're the one
constantly picking nits and claiming factual air superiority all the time.

And there you have it. You've got issues when someone suggests you adhere
nappy-nap, young man.

lyalc
Guest
Posts: n/a

 12-04-2005
Actually, if you think about it, low speed systems are much, much easier to
detect/compromise, in a tempest sense.

Signal emissions are usually the first 5-20 harmonics of the clock speed.
A clock of 100 Mhz probably needs a receiving AND PROCESSING bandwidth of
500-1000 Mhz.

A clock speed of 3 Ghz can mean a processing bandwidth (analog or digital )
exceeding 10 Ghz.
That's a fairly expensive set of kit, super-computing scale, not suitcase
sized, portable gear, especially if you are looking for near-real-time
recovery, not SETI-style post analysis.
Often, these higher frequencies have much less energy/radiated power than
lower speed clocks, for a variety of technical reasons.
So the detection range (signal over noise) is probably much less,
potentially minimising the 'volume' of risk.

Just my 20cents worth.

Lyal

"nemo_outis" <(E-Mail Removed)> wrote in message
news:Xns9720749503131abcxyzcom@127.0.0.1...
> Juergen Nieveler <(E-Mail Removed)> wrote in
> news:(E-Mail Removed):
>
> > "nemo_outis" <(E-Mail Removed)> wrote:
> >
> >> If you would not notice somebody looking (or other forms of
> >> surrepitious observation and/or recording) there is something
> >> desperately wrong, either with you or with your environment.

> >
> > tempest-shielded?
> >
> > Juergen Nieveler

>
>
>
> Nope, not required as as a result of my risk and threat assessments. Nor
> is protection against laser interferometry on windows and a few other
> exotic attacks.
>
> However, I have posted on how to tackle threats such as Tempest related
> attacks, including my preference for older low-MHz laptops (lesser emsec
> concerns, no exposed cables, no need to isolate power supplies, possible

to
> use RF-shielded enclosures rather than shielded rooms, etc.).

Constructing
> full room-size high-MHz Faraday cages is a bear - the grounding aspects
> alone present significant challenges (as do seals, conduits, air exchange,
> etc.)
>
> Despite your gibe, physical security does not mean that one must always
> escalate to Fort Knox. No, it means that the level of physical security
> should be commensurate with the threats, the risks they pose, and the
> consequences of security breaches. However, all but the very lowest

levels
> of physical security require freedom from direct visual observation by
> others.
>
> But you knew that already; it's just fun to tease me
>
> Regards,
>
>