Re: [PATCH 05/18] crypto: Test restore of cleartext index from stashed session keys

[David Bremner <david@tethera.net>]

Daniel Kahn Gillmor <dkg@fifthhorseman.net> writes:

> On Tue 2017-11-14 09:13:52 -0400, David Bremner wrote:
>> Daniel Kahn Gillmor <dkg@fifthhorseman.net> writes:
>>
>>> If you've got a notmuch dump that includes stashed session keys for
>>> every decrypted message, and you've got your message archive, you
>>> should be able to get back to the same index that you had before.
>>
>> Out of curiousity, have you given any thought to what happens when
>> someone sends a message with the same message-id but a different
>> session-key? it seems like the user can potentially lose access to the
>> encrypted message.
>
> yep!  I even have that case in my own mailbox due to messages i've sent
> to schleuder encrypted mailing lists to which i'm also subscribed.
>
> It works fine.  notmuch stashes both session keys against the message-id
> (you can have multiple properties with the same name as long as they
> have different values).  And upon decryption, it tries each session-key
> in succession.  This is a little bit sloppy (maybe it would be less
> sloppy to associate each message key with each version of the message
> somehow?), but it's significantly simpler and basically unnoticeable
> compared to the speedup gains provided by the rest of the series.
>
>          --dkg

Great!

d