Re: [IPsec] AES key lengths: draft-ietf-ipsecme-esp-ah-reqts

<Paul_Koning@Dell.com> Mon, 10 March 2014 16:58 UTC

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From: <Paul_Koning@Dell.com>
To: <paul@cypherpunks.ca>
Thread-Topic: [IPsec] AES key lengths: draft-ietf-ipsecme-esp-ah-reqts
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Date: Mon, 10 Mar 2014 16:58:07 +0000
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Subject: Re: [IPsec] AES key lengths: draft-ietf-ipsecme-esp-ah-reqts
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On Mar 10, 2014, at 12:45 PM, Paul Wouters <paul@cypherpunks.ca> wrote:

> On Mon, 10 Mar 2014, Paul_Koning@Dell.com wrote:
> 
>> That’s a good argument for a user choosing to use AES-128 rather than AES-256.  But it doesn’t really address why “SHOULD implement” isn’t justified — the implementation cost is trivial and if it isn’t used it has no performance impact.
> 
> It's not the implementation cost that matters. It is the GUI confusion.
> For example one vendor uses "aes" as aes128, and another vendor uses
> "aes" for aes256 (or aes_ctr or aes_cbc or aes_gcm). Each option we
> expose needlessly to the enduser is one more potential interop issue.

True.  But if you assume sufficiently foolish GUI designs, just about anything can be hard to use.  And I don’t think that good crypto design should be put at the mercy of people who can’t design a decent UI.  We know that it’s possible to get this right.

	paul