Re: I'll show you mine if you show me, er, mine

2005-03-03 Thread Dan Kaminsky

The description has virtually nothing to do with the actual algorithm 
proposed.  Follow the link in the article - http://www.stealth-attacks.info/ - 
for an actual - if informal - description.
  

There is no actual description publically available (there are three
completely different protocols described in the press).  I talked to the
author about this; he sent me a fourth, somewhat reasonable document. 
At *best*, this is something akin to SRP with the server constantly
proving its true nature with every character (yes, shoulder surfers get
to attack keys one at a time).  It could get pretty bad though, so
rather than support it or bash it, I'd just reserve judgement until it's
publically documented at Financial Crypto.

--Dan



Re: Dell to Add Security Chip to PCs

2005-02-04 Thread Dan Kaminsky

The best that can happen with TCPA is pretty good -
it could stop a lot of viruses and malware, for one
thing.
 

No, it can't.  That's the point; it's not like the code running inside 
the sandbox becomes magically exploitproof...it just becomes totally 
opaque to any external auditor.  A black hat takes an exploit, encrypts 
it to the public key exported by the TCPA-compliant environment (think 
about a worm that encrypts itself to each cached public key) and sends 
the newly unauditable structure out.  Sure, the worm can only manipulate 
data inside the sandbox, but when the whole *idea* is to put everything 
valuable inside these safe sandboxes, that's not exactly comforting.

--Dan


Re: Dell to Add Security Chip to PCs

2005-02-03 Thread Dan Kaminsky
Uh, you *really* have no idea how much the black hat community is 
looking forward to TCPA.  For example, Office is going to have core 
components running inside a protected environment totally immune to 
antivirus.  Since these components are going to be managing 
cryptographic operations, the well defined API exposed from within the 
sandbox will have arbitrary content going in, and opaque content coming 
out.  Malware goes in (there's not a executable environment created that 
can't be exploited), sets up shop, has no need to be stealthy due to the 
complete blockage of AV monitors and cleaners, and does what it wants to 
the plaintext and ciphertext (alters content, changes keys) before 
emitting it back out the opaque outbound interface.

So, no FUD, you lose :)
--Dan

Erwann ABALEA wrote:
On Wed, 2 Feb 2005, Trei, Peter wrote:
 

Seeing as it comes out of the TCG, this is almost certainly
the enabling hardware for Palladium/NGSCB. Its a part of
your computer which you may not have full control over.
   

Please stop relaying FUD. You have full control over your PC, even if this
one is equiped with a TCPA chip. See the TCPA chip as a hardware security
module integrated into your PC. An API exists to use it, and one if the
functions of this API is 'take ownership', which has the effect of
erasing it and regenerating new internal keys.