Re: [Acme] Why "HTTP verification"

[Peter Bowen <[e-mail]>]

On Tue, Dec 2, 2014 at 11:44 AM, Viktor Dukhovni <[e-mail]> wrote:
> On Tue, Dec 02, 2014 at 11:15:40AM -0800, Peter Bowen wrote:
>
>> The primary case where I see a problem is when the site already has a
>> trusted certificate and wants to use ACME to get a new certificate.
>> They are unlikely to want to replace their working certificate with a
>> self-signed certificate.  So the proof would need to happen at the
>> HTTP layer, not the TLS layer.
>
> They can request a certificate for the same private key.  The
> "self-signed" thing so not precise.  The real requirement would be
> *some* certificate with the same key, not necessarily self-signed.
> So issued by another CA should be fine.

I would hope that many sites would have a policy of rotating their
private key, as a reasonable number of clients still use the same key
for identification and key exchange.  I'm not sure what the protocol
should look like for proving possession of the old and new keys at the
same time, but it would be good to support this case.

Thanks,
Peter