Oct 30 & Nov 17, 2021 by Leo Chen & Rongjian Lan

Summary

This is a design doc of the allowlist feature for harmony.

The proposal is being discussed within the validator community to add external leaders to the consensus using allowlist.

https://talk.harmony.one/t/hip-18-allowlist-for-external-leaders/4329/20

Background

Leaders in the Harmony protocol are still run by the nodes owned by the team currently. Leaders rotate only when the current leaders become unavailable, using the view change algorithm. The end goal of the protocol is to have all leaders run by external validators and rotate on a regular basis using secure resharding. However, we are still far from that goal at the moment. So, in the meantime, adding a list of external validators as leaders is an interim solution to fully engage the community and prepare for full decentralization.

Pros and Cons

The pros of adding external validators as leaders are:

• verify the technical design of the external validators
• get external validators ready for the eventual goals
• empower the validator community to govern the network

The cons of adding external validators as leaders right now are:

• uptime risk if external leaders fail
• security risk if external leaders are corrupted
• performance risk if external leaders are not powerful enough

Mitigations

• add trusted external validators to allow list, 5 per shard, starting with one shard
• clearly specify the uptime requirement and one node requirement
• keep one internal nodes as the default leader