Re: [TLS] I-D Action: draft-ietf-tls-negotiated-ff-dhe-02.txt

[Alyssa Rowan <[e-mail]>]

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On 24/10/2014 15:55, Peter Gutmann wrote:

> Re-doing the crypto to implement and support ECC may happen in five
>  to ten years, if there's enough code space in the flash.

So, you want to use 768-bit groups… for five to ten years… yeah, I'm
not too comfortable with that.

>> No, it's blessing them even to list them. People will probably 
>> implement what we specify.
> So put in a note saying that use isn't recommended.

…or, you could not put it in.

Intentionally specifying something new, in a security-oriented RFC,
that by the way you absolutely shouldn't use because it's insecure,
seems a bit reckless to me.

> ("it works, don't touch it any more").

I think we really ought to be getting rid of skeletons in the closet,
not adding new ones - despite Hallowe'en being next week, and that
phrase being appropriately spine-chilling! ;)

(BTW: Lost, embedded devices; too small to use a 2048-bit group for…
some reason? RAM?; yet negotiate (768|1024|1536) DHE…

…wild guess here: RSA key signing this exchange is totally
minty-fresh? …and actually checked? With something that isn't MD5? And
the DHE keys aren't generated with 2 bits of entropy and a potato
because the $2.50 intern lunch budget didn't cover an RNG? <g>)

>> 768 and 1024 are crackable today by any reasonably well-funded 
>> adversary with access to a chip fab, as you well know;
> ... who probably won't be using that capability to attack a power 
> meter, or a flow monitor

…or a centrifuge? ¬_¬

SCADA security - or lack thereof - is a very big problem. I don't
agree that specifying groups for future use that we _know_ are too
small, helps do anything but make it worse.

- -- 
/akr
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