Summary: Windows GUI recommendation for USB disk
Henry Hertz Hobbit
hhhobbit at securemecca.net
Sat Nov 4 00:47:25 CET 2006
On Fri, 2006-11-03 at 09:40 -0600, Robert J. Hansen wrote:
> Ryan Malayter wrote:
> > When encrypting to a *.7z file, 7-zip uses AES-256 in CBC mode, with
> > a passphrase-to-key function based on SHA-256. This is actually
> > stronger than most cipher preferences on OpenPGP keys.
> This may be just my own personal quirk, but it seems misleading to me to
> describe AES256 as "stronger" than, say, AES128. The threshold just to
> break AES128 is so immense that it may as well be a brick wall;
> describing AES256 as "stronger" just means the brick wall is, well,
> still a brick wall. Once you reach a certain threshold point as far as
> resistance to brute-force attacks, to really make something "stronger"
> requires introducing resistance to other kinds of attacks.
> E.g., I'd say that an 3DES hardware token guarded by a fireteam of armed
> Marines is far stronger than an AES256 key stored on a PC running
> unpatched Windows 95 on an always-on unfirewalled Internet connection,
> despite the fact the AES256 key has about 144 bits more keyspace.
> Let's just describe 7zip as using strong crypto, and leave it at that. :)
I already told Ryan that WinZip also has both AES128 and AES256. I
did a download of it yesterday and found that out for sure. I also
asked Ryan to do a test to find if WinZip <-> 7-Zip can share their
AES encrypted files.
You are absolutely correct in saying that they are both brick walls.
The weakness is not in the algorithm or even the number of bits you
use. I primarily use TWOFISH, but it is still that brick wall. It
just has different colored bricks. The weakness is normally in the
pass-phrase (password). Trying as hard as I can, I have had nothing
but grief in trying to train people in how to create them and have
finally understood it is going to be "pencil", no matter what for
some people. That is the limit of their memory and imagination.
Well, even the smart ones will resort to using "joshua"
(case-insensitive of course). Go look at War-Games if you don't
know where the pass-phrases came from.
I gave Ryan the humorous example of a fellow student who locked
their terminal at school while they went to the restroom. I told
him I could hack through his screen password. I did, and changed
it to another one. I had noticed him looking at the pictures of
nature on the wall and fixating on a green frog. I hacked in with
only about four attempts, then locked it again with a pass-phrase
indicating the hack. The strongest encryption in the world is
useless without a GOOD password or pass-phrase. It may be useless
even then with a keyboard logger. Kevin Mitnick didn't exploit
weaknesses in systems so much as exploiting the weaknesses in
This all kind of begs the question though. I can't even get the
files to another security researcher (Mike Burgess) because the
Symantec AV scanner on Comcast's SMTP server barfs on a PLAIN
zipped file right now. It attaches my message (with the ZIP
attachment) to a message saying it can't scan the zip file.
It will ALWAYS do that if I encrypt the zip file (whether I use
the salt-cipher or AES) that I zip. But I can attach a normal
zipped file and use GnuPG (OpenPGP) encryption and it sails
right on through. I can see my zip attachments that are
bounced in both Thunderbird and Evolution, but Mike can't see
them in Outlook (any pointers Outlook people?). If the message
doesn't make it the other side and that is what you wanted to
do in the first place the encryption is useless.
Systems depend on EACH AND EVERY ELEMENT that go into their
creation. Passwords and pass-phrases are what I will attack
every time, not the brute force of something even as lowly as
CAST5 or 3DES. I GUARANTEE that unless people are trained in
how to create novel passwords and pass-phrases AND *DO* IT, I
WILL probably be successful. And I only have a normal IQ.
Don't go up against the geniuses like Mitnick, Schneier and
Werner and others. They will beat you every time.
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