Fwd: Re: [Cryptography] Encryption opinion

A relevant post from the Cryptography list:

====== Forwarded Message ======
Date: 8/27/14 8:18 AM
Received: 8/27/14 3:26 PM -0400
From: [email protected] (Jerry Leichter)
To: [email protected] (Watson Ladd)
CC: [email protected] (Paul Ferguson), 
cryptography-of7zbby7T3pWk0Htik3J/[email protected] (Cryptography),
     [email protected] (ianG)

On Aug 26, 2014, at 11:06 PM, Watson Ladd 
<[email protected]> wrote:
>The solutions to these problems [insecurity of end nodes emerged in the 1950-1960's, and as late as the 1980's the Orange Book made the sort of system that CapOS, Coyote, and Ethos attempted to make the gold standard. No one did it
>for a variety of reasons, but you certainly could with enough work,
>make a single-user system with the property that all access to
>documents is authorized by a UI action, or use Keychain/factotum style
>auth for all SSH private keys....
*No* solution to these problems has *ever* emerged.  *Proposals* 
for solutions have been all the rage, and various experimental 
implementations have been done, but none has succeeded - if by 
"success" you mean not "led to publishable papers" but "led to 
fieldable (and fielded) useful (and used) systems".

The Rainbow series of papers, of which the Orange Book was 
simply the best known, was an attempt to turn the nominal 
structure of *military* systems into the basis for secure 
systems for the entire world.  In practice, it didn't even 
satisfy the requirements of the military.  I still have a copy 
of the entire Rainbow series somewhere, but let's face it:  It's 
a historical curiosity.

PKI's "solved the problem" of key distribution and MITM 
attacks.  RSA "solved the problem" of signatures.  And it's not 
just security:  Nelson's dissertation on RPC (or CORBA, if you 
want to talk about the most complete widely-available 
realization of those ideas) "solved the problem" of distributed 
computation.  A variety of papers, include Hoare's CSP, "solved 
the problem" of parallel programming.  Codd's definition of the 
relational algebra and a whole bunch of work on transactions 
"solved the problem" of databases.  *And these are examples of 
ideas that actually have seen wide and continuing success!*  But 
the problems they've "solved" have proved to be broader than 
originally thought.  If you want to list other "solutions" that 
have have simply vanished over they years, they are easy to 
find.  Thinking Machines hardware and CM* "solved the problem" 
of massive parallel computation.  C++ "solved the problem" of 
object-oriented programming for the masses.  And, hell, next 
year will
   absolutely, definitely be the year of Linux on the desktop.

When you see ideas that have been sold for years as a solution 
to a significant problem, but somehow have never quite caught on 
- two that come to mind immediately are functional languages and 
capability-based systems - you have to ask yourself:  Might 
there be a reason?  Might there be something missing - perhaps 
just a small thing?  Sometimes that's enough!

For capability-based systems, I think *the* hard problem is 
configurability:  How do you turn an access policy defined in 
human terms into a set of capabilities that accurately and 
completely implements the policy?  Given a set of capabilities, 
how do you turn it into something human beings can actually 
understand?  The *implications* of security policies - what is 
*actually* granted or forbidden, not as a result of the explicit 
policies but as a result of what they imply - is something 
that's difficult or impossible to understand, whether the 
policies are stated in English or in some formal capability 
language.  In human-based systems, we get around our lack of 
understanding by allowing humans to override the policies (which 
also opens the system up to social engineering).  When we freeze 
the enforcement of such policies into code, we often produce 
unusable systems.

Note that I'm not claiming capability-based systems *can't* 
work.  I'm saying that *even on the theoretical side*, we need 
to do more work on *known issues*; and on the practical, 
fieldable, fielded side - we have almost no experience.

Claims that capability-based systems can, *in practice*, solve 
the difficult issues of end-point security at Internet scale 
simply cannot be supported today.

                                                         -- Jerry

_______________________________________________
The cryptography mailing list
cryptography-of7zbby7T3pWk0Htik3J/[email protected]
http://www.metzdowd.com/mailman/listinfo/cryptography

====== End Forwarded Message ======
-------------------------------------------------------------------------
Bill Frantz        | The first thing you need when  | Periwinkle
(408)356-8506      | using a perimeter defense is a | 16345 
Englewood Ave
www.pwpconsult.com | perimeter.                     | Los Gatos, 
CA 95032