On 2011-02-21 at 11:53 -0800, Tom Perrine wrote:
> I just saw this blog post by the Grumpy Troll:
> http://bridge.grumpy-troll.org/2011/01/openssh.html

Thanks for the shout-out. :)

> How about you?  Is ECC revolutionary, just for tinfoil hats, or no value at
> all?  I've put together a quick Survey Monkey survey to gauge interest in
> ECC in SSH:

Since you don't ask for *why* in the survey: I believe in algorithm
agility and not being critically dependent upon any one system.  Crypto
strength is mostly about what we don't know how to do, not what we can
prove.  As Bruce Schneier is fond of saying, attacks against a
crypto-system only ever get better.

Thus I deploy both RSA and DSA keys, both host and client, so that in
the event of a calamity I can turn one off and still have the other to
use.  A calamity might be a crypto break-through, or it might be the
discovery of a bug like the one which bit Debian systems a few years
back, having seriously weakened keys.

It's not that I have any reason to fear that RSA or DSA might be weak,
but that I have no reason to believe that either is too weak, so running
both in parallel does not hurt security and does improve my ability to
respond to a changing environment, which at some point in time will
critically improve my security.

Likewise, ECC and the ECDSA support: it's a different system, built on
different primitives.  I'm not a cryptanalyst to judge the security of
ECC, I trust what the experts say.  I am a sysadmin opposed to single
points of failure and ECC is good enough that I like being able to
deploy it in parallel, so that I'm not just dependent upon prime number
factorisation.

It might be that the next breakthrough will take down ECC, not RSA, and
I'll end up having to disable it and those who didn't deploy it will
laugh.  But it could be that the next breakthrough hurts RSA instead.
*shrug*  I prepare for the worst and cover my bases.

In closing, I'll note that when the NSA tinkered with DES there was a
lot of paranoia, but when public cryptography finally caught up it
turned out that the NSA had made DES stronger.  The evidence, rather
than loud-mouthing, to date suggests that the NSA does its job honestly,
making real crypto stronger and protecting the US government and public
in this manner.  With the NSA pushing NIST to push to migrate federal
systems to ECC, I'm not going to go out screaming that "we must move to
ECC", but I am going to heed the advice and buy myself the flexibility
by deploying a third hostkey and client pubkey algorithm.

-Phil, The Grumpy Troll
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