Re: [perpass] TLS/SSL Key Rotation

[Yakov Shafranovich <[e-mail]>]

On Tue, Sep 3, 2013 at 7:43 PM, Stephen Farrell
<[e-mail]> wrote:
> On 09/04/2013 12:18 AM, Yakov Shafranovich wrote:
>> On Tue, Sep 3, 2013 at 8:47 AM, Stephen Farrell
>> <[e-mail]> wrote:
>>> On 09/03/2013 01:11 PM, Yakov Shafranovich wrote:
...
>>
>> or forcefully disclosed via a court order or other legal mechanism.
>> The shorter the interval, the less data would be available to the
>> potential attacker. There has been media discussion about this with
>> the US Government [1] where providers are forced to hand over their
>> keys.
>
> Right, but if the TLAs come calling, and the service provider's
> response is to hand over today's RSA private key and then roll a
> new keypair then you'll have an unhappy TLA, who'll come right
> back calling again. The phone records thing (court order being
> renewed every 3 months or whatever it was) also seems to argue
> that rolling key pairs isn't going to help really.
>

One could envision a scenario where a small group of users or a
particular user is being targeted by the court order for a limited
period of time. Having regular key rotation will not stop the TLAs
from reading everyone's email but will limit the damage once the key
rotates.

Yakov