Re: [Cfrg] [TLS] 3DES diediedie

[Derek Atkins <[e-mail]>]

Peter Gutmann <[e-mail]> writes:

> Richard Hartmann <[e-mail]> writes:
>
>>Is it correct when I say that the embedded programmers you talked to don't 
>>care about any form of DES as they need/must/prefer to do AES, anyway?
>
> The only data point I have is that every time I've tried to disable DES in
> a new release (and by DES I mean single DES, not 3DES) I've had a chorus of 
> complaints about it vanishing.  Unfortunately I don't have anything more
> than that, you only find out about things like this when they break stuff.
> Certainly DES still sees a surprising amount of use, and in many cases it's
> quite justified, whatever you're protecting is adequately safeguarded with
> DES.  For example burglar alarms, if they use real encryption (far too many
> use "encryption" that would more accurately be described as data masking),
> often use DES, no doubt based on Microchip App Note 583 or freely available
> source like despiccable, which runs in 20 bytes of RAM (if your burglar alarm
> is advertised as having a "RISC based CPU" then it's probably using a PIC,
> having a processor so spartan it can barely add is now a marketing feature if
> you use the right name for it).  They'll be using DES forever, because the 
> entire environment they operate in runs DES.
>
>>If yes, there's no reason in the embedded world that would prevent a 
>>diediedie.
>
> See above.  You're not going to get rid of DES.  And, as I've pointed out
> earlier, the embedded world won't even know your diediedie exists, and if
> it's pointed out to them they'll ignore it.  Alarms, for example, send data
> quantities measured in bytes, so some academic attack that would take 500 
> million years to acquire the necessary data isn't going to lose anyone any 
> sleep.  It's a nice piece of work, but you need to look at what practical 
> effect it has on real, deployed systems...

EXACTLY!

> Peter.

-derek

-- 
       Derek Atkins                 617-623-3745
       [e-mail]             www.ihtfp.com
       Computer and Internet Security Consultant