Re: [openpgp] Work items for openpgp relaunch: Content-type equivalent

[Dominik Schuermann <[e-mail]>]

Hi Werner,

On 03/15/2015 08:43 PM, Werner Koch wrote:
> On Sat, 14 Mar 2015 21:49, [e-mail] said:
> 
>> There’s one missing piece, the equivalent of HTTP Content-type.  You can
>> easily encrypt anything - a message, a picture, a video - and send it off
> 
> What about using RFC-3156 PGP/MIME and set the Content-type? 

If setting the Content-type to something different than
"application/octet-stream" would leak the Content-type to others or do
you have a different usage in mind?

There are related problems to this:
- RFC 3156 only considers the usage of ASCII armored data, we also like
to share encrypted binary files.
- Currently we "share" a blob with Content-type
"application/octet-stream", while we actually want something more
concrete that identifies OpenPGP-encrypted blobs. We don't use
"application/pgp-encrypted" as it is specified to only hold the version
number.

> 
> IIRC, a new flag 'm' for the Literal Data Packet was once suggest to
> indicate the data has a MIME structure.  That would allow to convey all
> kind of meta information using a matured standard.

The related draft is here:
http://tools.ietf.org/html/draft-moscaritolo-openpgp-literal-01

I like this approach as it hides the MIME type in the encrypted header.
Having this and a MIME type for OpenPGP-encrypted blobs would solve the
problem for us, what about "application/pgp-encryption"?

Maybe I am overseeing something, so any pointers are appreciated :)

Regards
Dominik