Re: [E2ee] Reducing Plaintext Metadata in E2EE Systems

[Matthew Finkel <[e-mail]>]

Hi Mallory,

That's great, thank you! I apologize for dropping this.

Thanks,
Matthew

On Tue, Oct 19, 2021 at 11:44:21AM -0400, Mallory Knodel wrote:
> Hi Matthew,
> 
> I added a section under Optional/desirable features that says:
> 
> Metadata obfuscation: Steps should be taken to minimize metadata such as
> user obfuscating IP addresses, reducing non-routing metadata, and avoiding
> extraneous message headers can enhance the confidentiality and security
> features of E2EE systems.
> 
> -Mallory
> 
> On 7/29/21 10:27 AM, Mallory Knodel wrote:
> > 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
> gpg fingerprint :: E3EB 63E0 65A3 B240 BCD9 B071 0C32 A271 BD3C C780
> 
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