[SSL Observatory] Diginotar broken arrow as a tour-de-force of PKI fail
Adam Langley
agl at google.com
Wed Sep 14 05:18:59 PDT 2011
On Wed, Sep 14, 2011 at 7:44 AM, Rob Stradling <rob.stradling at comodo.com> wrote:
> OK. Any ideas on how to solve the *how* problem?
Thankfully we have a much easier job than many time sync problems: we
can be off by a minute and it doesn't matter.
Based on that, I think a service that replies with a signed message
that contains the current time and echos an nonce challenge is pretty
obvious. There are operational problems of course as we're building a
service that must run continuously. We have to have a reasonable plan
for running these things for 20 years. (And you can't expire
certificates used in a clock protocol. Do the clients query n-of-m
servers with different keys and check that they agree?)
But it can be done if the benefits of having clocks is sufficient.
Cheers
AGL
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