[liberationtech] An email service that requires GPG/PGP?

[Crypto]

On 8/9/2013 1:07 PM, Griffin Boyce wrote:
>   This probably sounds very strange, but *what if* someone ran an email
> service that required that all mails be GPG encrypted?
> 
>   So here's my idea: Barring the honor system, it would require a filter
> to look at message content to check for PGP headers.  And if said
> headers didn't exist, the message doesn't get sent.[1] There's no "Sent
> Mail" folder on the server, so if you want a copy, you'd need to have
> Thunderbird (etc) set up to store them locally.
> 
>   It wouldn't protect from metadata collection, but it would at least
> (to some extent) protect people from their own poor security decisions
> while emphasizing that options exist to protect themselves.
> 
> Considerations:
>     * This assumes that an order would arrive to disable PGP filter and
> enable a sent folder (eg, this idea assumes metadata is unprotected)
> 
>     * Those playing at home may recognize this as a naive Bayes
> classifier, given that the presence of PGP headers don't necessarily
> mean the actual message is encrypted. There are other (heavier) steps
> that could be taken, like checking for encryption on outbound with SJCL,
> but I think that probability is on our side here.
> 
>     * In the face of an NSL, the service would realistically either fall
> back to policy (removing tech-based enforcement by order) or shut down
> entirely.
> 
>   What does everyone think? Is this totally nuts or what?
> 
> best,
> Griffin

Many years ago I modified a version of Majordomo to work with PGP. It
was called PGPdomo. I got interested in other things and let it fall by
the wayside. I don't have a copy of it anymore. You might be able to
Google PGPdomo and find an old version of it floating around. You are
welcome to use it as a model. The only problem was that it was very
CPU-intensive as it encrypted each and ever message to each subscriber
individually.

-- 
Crypto

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