Re: [TLS] RC4 Considered Harmful (Was: RC4 deprecation path)

On Sat, Apr 19, 2014 at 1:50 PM, Yoav Nir <ynir.ietf@gmail.com> wrote:
>
> On Apr 19, 2014, at 11:10 PM, Alyssa Rowan <akr@akr.io> wrote:
>
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>> On 19/04/2014 20:28, Yoav Nir wrote:
>>
>>> As long as the client is required to support such servers, I guess
>>> we have to live with it.
>>
>> I think the only correct deprecation path to recommend is the one
>> that's on the table right now: the off switch.
>>
>> Warn your users if you have to. But don't negotiate RC4 without a
>> click-through warning.
>
> I can probably do it, as long as I provide a configuration to re-enable it. But that’s me.
>
> Check out the survey that Kurt posted a link to. 1.56% or TLS servers support only RC4. Browsers are distributed for free, and each of the big ones is installed in hundreds of millions of copies. They can’t afford having support calls, and they can’t afford the bad publicity that comes with “some sites don’t work with this browser”.  What Microsoft is doing is the best we can hope for for now.

What happens 5 years from now when those servers still aren't updated?
I think the best we can do is stop configurations of new software from
supporting it.

Furthermore, we need to ensure that we never face this situation
again. RC4 needed to be depreciated starting with WEP. In the future
we will need to have much more aggressive depreciation, better
guidance on what to support and in what order to prefer ciphersuites.

Sincerely,
Watson Ladd

>
> Yoav
>
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