ERC 735: Claim Holder Registry vs. in contract

Contents

• Central claim registry
  • PROs
  • CONs
• In-Contract claims
  • PROs
  • CONs

This is part of the discussion for https://github.com/ethereum/EIPs/issues/735 (Related comment) This is a collaborative list of PROs and CONs to gather advantages for both sides.

Central claim registry

PROs

• standardised, e.g. functionality known which prevents cheating
• central reference point
• claim addition and removal can have complex processes, all standardised

CONs

• will mainly be useful for pure ethereum accounts or smart contracts. There is no advantage over in-contract claims when adding signatures to them
• Will be hard to change, or to improve over time, as the code once deployed is fixed, or needs a complicated upgrade mechanism

In-Contract claims

PROs

• Claims are at the spot where people interact with the identity itself (this is what the third party receives as info anyway when interacting with this identity/person)
• Behaviour how claims are added can be customised (e.g. an identity would approve added claims, an ICO smart contract may just accept any without approval to show validity)
• Claims are verified through signatures, not the adding logic (as it can not be controlled)
• Claims can be removed/made invalid, if the issuer removes the key he signed with from its identity.
• The claim scheme can be more freely arranged
• as the focus is on signatures, those can be new types in the future, and interaction is not necessarily (Ethereum) blockchain specific.

CONs

• Claim addition can't be trusted (validation of the signature count is important)
• verifying claim signatures on chain can be costly.
• claims retrieval can be not follow standers and causes issues (leads to invalid/incompatible standard)
• Adds a lot of complexity/is more complicated to implement
• Requires more gas due to added complexity

Please feel free to add. Be aware that one claim or key can easily reference a claim registry, so these standards could work perfectly along side each other.