Subject: [Pearg] IP address Privacy Interim Follow up - Reputation System

From: Matthew Finkel <[email-masked]>
Date: Thu, 21 Jan 2021 15:38:16 +0000

Hi Everyone,

I'd like to follow up on the topic of reputation systems we briefly
touched on Tuesday. I'd like to understand the criteria of a system that
can help the Internet move towards deprecating IP addresses as a
fundamental signal in account-security/anti-fraud/anti-abuse systems.

>From the perspective of a web user agent, I'll start with the following
properties:

  - A reputation and its associated identity must not be linkable
    - This excludes the user and, possibly, a "reputation provider"
  - A reputation must not be universally unique
    - I suggest bucketing reputation into ~5 sets
  - A reputation must not be a tracking vector
    - Two "proofs of reputation" must not be linkable, neither across
      sites nor on the same site.
  - A client must be able to know (or query) its recent reputation
  - A service provider must be able to increase and decrease a
    reputation
  - A client must only use a recent reputation
    - A reputation should become stale and invalid within a short period
      of time
  - A client must be able to audit its reputation
  - A client must be able to dispute changes in its reputation
  - transitioning from a "bad" reputation to a "good" reputation should
    be reasonably possible
  - Computing a reputation must be well defined
  - The system must support "anonymous" identities
    - A client must be able to create a new and unique reputation not
      linkable to previous reputations or identities
  - A reputation must not be influenced by an associated IP address

While these are not all hard requirements, it is important that this
system doesn't become a "virtual credit bureau" where someone's
reputation is based on black magic and good fortune.

As a meta comment, I'm relatively new to IETF/IRTF processes, so I
appreciate recommendations on how this discussion should proceed.

Thanks,
Matt

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From: Shivan Kaul Sahib <[email-masked]>
Date: Tue, 26 Jan 2021 16:23:08 -0800

Hi Matt, the Privacy Pass protocol being standardized at the IETF has
similar use cases: https://datatracker.ietf.org/wg/privacypass/documents. A
good way to drive discussion is to put together an Internet Draft that
folks can review and comment on!

On Thu, Jan 21, 2021 at 7:38 AM Matthew Finkel <[email-masked]>
wrote:

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From: Matthew Finkel <[email-masked]>
Date: Wed, 27 Jan 2021 03:31:20 +0000

Hi Shivan,

Thanks for this guidance. I haven't followed the PrivacyPass
standardization effort since early last year, so I'll review that before
starting on an I-D. I'll reply here if the new PrivacyPass protocol does
not seem appropriate for this use case, and I'll appreciate
collaborating with someone who works on the service-side and knows the
challenges there.