[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [reformatted] how secure can privasoft be?


Hello [email protected]
  and [email protected] (Cypherpunks Mailing List)
  and [email protected] (Futplex)
F. writes:

> > The cryptographic engine of PrivaSoft
> > 
> > PrivaSoft uses a pseudo-random generator that is seeded by a 9 digit number 
> > uniformly normalized from the user's secret key.  The engine is proprietary, 
> > designed according to the rules of modern cryptology to make the best use of 
> > the allowable key length.
> This seems paradoxical. PrivaSoft uses a key approximately 30 bits long. It
> Two possible explanations I can imagine are:
> (0) PrivaSoft actually uses a key longer than 9 digits, and someone just made

Could it be 9 hex digits = 36 bits?

Perhaps there's an even bigger paradox in there:
   The engine is proprietary, designed according to the rules of modern

Now I'm not familiar with the rules cited, but wouldn't proprietary
tend to go against them?

> [...]
> > The use of default keys

> meant to resist attacks based on the cryptanalyst gaining access to many 
> ciphertexts, even if all were encrypted with a single key.

Perhaps theirs isn't? Could be a Freudian slip, you know...

> [...]
> > A simple example:  For a short message, increasing the font 
> > size of the text by a factor of 10 will significantly increase the time 
> > required for breaking the encryption.
> Anyone know how to get 120 point text in LaTeX ?

Don't worry, the whole thing sounds bogus anyway. I'd say a larger
font would make it *easier* to break (more correlation per pixel).
They probably think it'll be harder because there's more pixels.

In the original message (NOTE CHANGE IN INDENT!):

> From: [email protected]


> Introduction
> PrivaSoft is a communication security product, and the user is entitled to
> know how secure it is.  This document addresses the question of cryptographic 
> strength of PrivaSoft.

No it doesn't.

> Export license regulations
> In some advanced countries, cryptographic products are categorized as 
> "munitions" and their use, sale or exportation is controlled by local 
> licensing regulations.  PrivaSoft has obtained an export license from the 
> governments of Israel and the USA.  Licenses in other countries are obtained 

All right, I guess it does. USA approved export, so it must be very weak.

> The basic intention of this regulation is to protect the state from abuse of 
> too strong cryptographic products by terrorists and criminals.

Is it? I think there are one or two people on this list who think the
intention is otherwise...

> The use of default keys
> This is done by using the pseudo-
> random "key extension" feature which is described in the PrivaSoft user's 
> guide.

Do they mean "salt"? If so why don't they say it?
If not, what *do* they mean?

> The information contents a clear message

This is a strange title (I suspect "of" dropped out), but it might
well sum it all up :-)

> If a cryptographic product is properly designed, then the almost only way to 

A big "if", if I might say so.

> a significant 
> portion of the page must be reconstructed, and a significant amount of 
> mathematical correlation must be calculated between neighboring areas of the 
> image, before the cracking software can tell whether the candidate key is 

This can at most buy you a constant factor - useful, but not very.
I doubt the two uses of "significant", too. Anybody remember those
diagrams in Typing textbooks about the layout of a letter?

> Customized versions of PrivaSoft
> The cryptographic engine can be customer-furnished and customer integrated, 

What do they mean by this bit?

Sorry about being so negative, but it is necessary when evaluating security.

- --
If you want an answer, please mail to <[email protected]>.
On sweeney, I may delete without reading!
PGP 463A14D5 (but it's at home so it'll take a day or two)
PGP EF0607F9 (but it's at uni so don't rely on it too much)

Version: 2.6.2i