Implement Revocation and Ban Lists for Sybil Detection

[erichfi]

User Story:

As a platform manager, I want to revoke scores and credentials of users involved in Sybil Rings and ensure they are banned from claiming specific credentials and stamps, so that I can maintain the integrity and security of Passport XYZ by preventing misuse and gaming of the system.

Acceptance Criteria

GIVEN certain user addresses identified as part of Sybil Rings or engaging in suspicious activities, WHEN I upload a CSV with the details of this addresses and their credentials in the django revocation list THEN this respective credentials must be revoked AND they should not be displayed any more in the Passport App <<<--- is this true? Or do we want to label them as Revoked AND no points should be counted towards the score for these stamps

GIVEN certain user addresses identified as part of Sybil Rings or engaging in suspicious activities, WHEN I upload a CSV with the details of this addresses and their credentials in the django ban list THEN this respective addresses should not be allowed to verify the flagged credentials until the ban is lifted or expires AND they when trying to verify a banned stamp, they should receive a correct error message highlighting the ban <<<--- is this correct?

Product & Design Links:

N/A

Tech Details:

• Develop and maintain a revocation list in line with VC specification variants, enabling credential revocation for detected Sybil behaviour
  • this for example is a specification for a revocation list https://www.w3.org/TR/vc-data-model-2.0/#status
• Implement a ban list mechanism preventing credential claims within defined timeframes (temporary and permanent).
• Ensure seamless integration with existing architecture, accommodating potential future on-chain revocation needs.
• Ban / Revocation Tiers:
  1. Temporarily ban a hash from the system
  2. Permanently ban a hash from the system
  3. Temporarily ban a stamp of a user
  4. Permanently ban a stamp of a user
  5. Temporarily ban an account of a user
  6. Permanently ban an account of a user
• Make the temporary ban duration times configurable
• DB Table 1 What type of ban (stamp, hash, account) 2 Identifier 3 Time frame / duration

Open Questions:

• [ ] How granular should the revocation and ban be? Is it at the individual credential or user account level?
• [ ] What are the potential impacts on scoring and legitimacy if on-chain credentials are not initially incorporated into this system?
• [ ] How will user disputes or appeals against revocation or banning be managed?

Notes/Assumptions:

• The default specification for revocation lists needs modification to include temporary locks.
• Initial implementation focuses on non-on-chain credentials; further investigation into on-chain revocation is desired for future iterations.

[nutrina]

@erichfi regarding the ban list, what exactly should we ban? a. shall we ban an address from claiming a certain provider (like address A is not allow to claim Google)? b. shall we ban a certain stamp hash from being claimed (i. e. we would ban a given ETH address or the Web3 stamps, and the account for the Web2 stamps) c. or both options

UI Questions:

• do we highlight revoked stamps in the Passport UI
• for the banned stamps, do we need anything else than just a proper error message in the Passport App

[lebraat]

Stupid question: why would we ban just a Stamp when we can just label the entire account suspicious?

Separately, +1 to having an appeal process.