CDR: Re: Rijndael & Hitachi

[Jay Sulzberger]

Excellent ideas.

And the place to start is with Arnold Reinhold's improvement to the
cyphers.

oo--JS.


On Wed, 11 Oct 2000, Ray Dillinger wrote:

> 
> 
> On Wed, 11 Oct 2000, Arnold G. Reinhold wrote:
> 
> >The fact that some people put Medeco's in glass doors, doesn't mean 
> >Medeco should never develop a better lock.
> 
> I don't have a problem with people who manufacture locks.  
> I have a problem with the people who sell them.  
> 
> A sign of irrational fear is when the thing that is the 
> *symbol* of security -- in this case the lock, or the cipher, 
> is made very strong -- but used in a way that does not afford 
> good *actual* security.  
> 
> If the fear of being burgled weren't at least partly 
> irrational, meaning if it were based mostly on experience 
> rather than mostly on fear -- we'd be seeing doors with 
> half-inch thick steel plates in them to provide the same 
> level of security as the medeco lock -- and reinforced 
> concrete walls to provide the same level of security as 
> the door.
> 
> Ditto ciphers.  A strong cipher is like that Medeco 
> lock, or even better - but if the "door" is a dumb 
> key management policy, or the key is easily guessable, 
> then what has been gained?  
> 
> Because what is a lock, really?  It makes it harder to 
> get in *without breaking anything*.  But actual burglars 
> could really care less whether they break some of your 
> stuff -- provided it's stuff they can't steal.  So if 
> actual burglars were as common as the people who sell 
> these fancy locks tend to make out in their sales pitches, 
> most folks would know, from experience, that burglars 
> who break a window or a door are far more common than 
> burglars who pick a lock -- and would be demanding 
> *actual* security, meaning windows, doors and walls made 
> of unbreakable stuff, rather than just *symbolic* security, 
> of a strong lock or a strong cipher. 
> 
> If you want to propose a "Paranoid Encryption Standard", 
> IE, a system for people who actually *DO* expect people 
> to spend several million bucks and hundreds of man-years
> and thousands of CPU-years trying to break it, then it's 
> going to have to encompass a hell of a lot more than 
> ciphers.  Start with physical machine security -- put 
> the box in a concrete bunker with armed guards, give it 
> a flat-panel monitor and roll your own drivers and video 
> hardware. Stick a thermite grenade with a photosensitive 
> fuse in the hard drive box. Make a continuous circuit 
> through all the case components, that will detect anybody 
> taking the case off, and blow the HD if the circuit's 
> broken. Do a couple dozen other things along this line, 
> and you'll have the physical security thing covered about 
> as well as your cipher protects the data. 
> 
> But you're not through yet -- you've got the lock and the 
> door, but burglars can still come in through the windows 
> and the walls.  You've got to do some real serious data 
> security as well. 
> 
> First of all, nothing unencrypted is EVER written to the 
> hard drive except a bootstrap loader that prompts for a 
> cipher key.  When it gets the cipher key, it reads and 
> attempts to unencrypt the rest of the boot record.  
> 
> There is NO swap partition, and no swapping OS is to be used. 
> 
> The system computes a new cipher key every day using a 
> cryptographically strong random number generator, and notifies 
> you of it in a pencil-and-paper cipher that you can solve. 
> (on high-entropy binary data, pencil-and-paper ciphers are 
> actually quite strong)  That's the key you would need to 
> use the following day.  If you don't log on for one day, 
> you will not have the key for the following day, period. 
> Thus, if someone seizes your box and you can hold out for 
> *one* day, the data is GONE. 
> 
> But the burglars can still come in, maybe, through the roof.
> 
> So just to make sure of it, put a timer in there that blows 
> the HD if it's ever been more than 24 hours since you were 
> last logged on.  
> 
> *There's* your paranoid encryption standard.  Use blowfish for 
> the cipher, and the cipher won't be the weakest point. 
> 
> 				Bear
> 
> 
>