Re: [E2ee] Reducing Plaintext Metadata in E2EE Systems

[Mallory Knodel <[e-mail]>]

Thanks a lot Matthew,

I agree that this should be a goal. Not all of the features should or 
could be part of every e2ee system, but the draft should demonstrate the 
"trajectory" of where the technology goes ideally.

Please do create a PR, I would be happy to review and merge.

-Mallory

On 7/29/21 10:12 AM, Matthew Finkel wrote:
> Hi all,
>
> This draft is very valuable, thanks to the authors for writing it. I'd
> like to call more attention to the importance of reducing plaintext
> metadata. The current draft contains:
>
>     Existing protocols are vulnerable to meta-data analysis, even though
>     meta-data is often much more sensitive than content.  Meta-data is
>     plaintext information that travels across the wire and includes
>     delivery-relevant details that central servers need such as the
>     account identity of end-points, timestamps, message size.  Meta-data
>     is difficult to obfuscate efficiently.
>
> The phrasing of this paragraph leads me to wonder if obfuscation of
> metadata should be included as a desirable feature. I don't mean to
> imply it's possible to eliminate leaking all metadata in all E2EE
> systems, but there is often some low-hanging fruit, like IP addresses or
> non-routing metadata, that an E2EE system can try to protect or
> obfuscate; e.g., MASQUE/OHTTP/Tor for IP addresses, and [0][1] for
> protecting some extraneous message headers. I can open a PR if this is
> helpful.
>
> Thanks,
> Matthew Finkel
>
> [0] https://datatracker.ietf.org/doc/html/draft-autocrypt-lamps-protected-headers
> [1] https://signal.org/blog/sealed-sender/
>
-- 
Mallory Knodel
CTO, Center for Democracy and Technology
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