[Outdated & Changed] Dynamic committee size and dynamic sharding: implementation phase

Update 17 July 2020


  • Refactor:
    • Implementation Shard Refactoring
    • Merge code from dev/master-consensus-optimized to dev/dynamic-committee-size
  • New Staking flow:
    • Implementation Spec


  • Refactor
    • Shard Committee local testing and fix bug
  • Review New Staking Flow implementation spec
  • Implement new staking flow

Update 27 July 2020


  • Refactor:
    • Implementation Both Beacon and Shard Refactoring. Ready for QC testing
  • New Staking Flow:
    • Low Level Technical Spec (sent out later in this week)
    • Finish 20% implementation


  • Refactor:
    • Testing with QC team
  • New Staking Flow:
    • Continue implementing

Update 3 Aug 2020

In progress:

  • Refactor:
    • Testing with QC team
  • New Staking flow: 40%
  • Unstake flow technical specification: 20% (estimated end date in this week)

Update 10 Aug 2020


  • Unstake flow technical specification

In progress:

  • Refactor:
    • Testing with QC team
  • New Staking flow: 60%
  • Unstake flow: begin implementing

Update 17 Aug 2020

This week our team had a nice-to-have debate about design pattern and code structure. The new-staking-flow code is refactored based on our solution. It took us three days but will be rewarded.

In progress:

  • Implementing unstake
  • Refactoring code of New-staking-flow and continue to implement
  • Testing finished part with QC team

Update 28 Aug 2020



  • Implementation of Unstake Feature
  • Implementation of New Swap/Assignment Rule

Let’s explain a little bit about these features. Both these features effect directly our dear end-user, especially those who run node.

  • Unstake feature is a desirable feature since our first day. It allows user to withdraw his/her stake amount whenever user’s node in candidate list, which mean it plays no role in any shards (neither committees in block creation phase nor committees in preparation phase). In short, Unstake feature tells one how long he/she must wait to get back one’s staking amount (in PRV).

  • New Swap/Assignment Rule makes Incognito’s consensus more secure and changes reward amount in short term duration.

    • The new assignment rule helps one’s node got assigned into one shard more quickly, but it must wait longer before earning something. In general, reward amount in one year might not change much. However, if you are lucky you will earn a lot more reward in the same duration compare to the current version.
    • The new swap rule allows us to development slashing feature easier.

In progres:

  • Review & Testing Unstake Feature
  • Review & Testing New Swap/Assignment Rule

Update 21 Sep 2020

The new swap rule (swap rule v2) which is implemented last month seem not meet our needs. So far, this month we are discussing how to implement it properly. The swap rule v2 allows beacon chain to force shard chain changing shard’s committees.

In progress:

  • Slashing node which continuously missing votes for blocks in one epoch
  • Re-design and implement swap rule v2

Update 25 Sep 2020


  • Review & Unit test swap rule v2.

In Progress:

  • Implement shard block creation v2 and integrate with swap rule v2.
  • Merge Code from Swap Rule V2 and continue to implement slashing module.

With this development speed, I am confident that we will finish implementing two task above by the end of next week (2 Otc 2020). After that, team will move to testing & debugging phase. I am so excited that team found a proper design for slashing flow after a couple times of trying.


Update 18 Oct 2020


  • Implementation of new Shard Block Creation V2. From now on, a new shard block is only allowed to created if it find a higher beacon block. Otherwise, shard chains will stop producing new block

  • New Swap (change committee) rule. This is a really big change to our consensus working mechanism. At first, we think that shard independently changing its committee after one epoch will make Incognito more secure. But seem that, it create more problem than helping the chain. The Shard chains and Beacon chain must synchronize too many kinds of information, which is very hard to get the same correct answer. The New Swap Rule, swap-rule-v2, forbid shard to change its committee by them self. Instead, the Beacon chain will force shard to change its committee. Less data to synchronize, less problem to tackle.

  • Slashing module by counting missing signatures from committees in 1 epoch creation. For example, if one shard creates 100 blocks in 1 epoch, each nodes must sign at least 50 blocks or it be force un-stake. This module is carried by the Beacon chain.

  • Documenting Implementation detail, integration testcase.

  • Refactoring a huge amount of code which covered by thoughtful unit-test.

In progress:

  • Review code
  • Local testing
  • Continuously defining new testcases
  • Integration

I am so glad that this feature is getting much better, clearer. It took us almost five months from researching to implementation, testing. A lot of re-design, re-work was conducted. If luck is on our side, this feature will be launched in testnet by the end of this month (October).

This is our specification link: https://docs.google.com/document/d/19KChrg0B2LmfT_t-K8vovCG-mXUkAYG88j5FQsKPXT4/edit#heading=h.k9idjn4fvxia


It would be useful, to me at least, that there is a process when this is rolled out that if a vNode is getting slashed there is some notification to user. Especially when this roles out, as currently I believe there may be vNodes incorrectly configured on the network, and due to the current setup the nodes are still earning even if they are missing blocks (or completely offline and unreachable). It would be nicer if when this is rolled out the nodes in committee that are not providing incorrect solutions/missing blocks were not initially penalized, but rather notified so validators could have an opportunity to fix any configuration issues they may have. Otherwise there may be quite a few validators that see drops without an understanding of why… Just something to consider.


Am I reading this correctly, that if your validator gets “slashed” it will be forced to unstake?


Thanks for sharing your thoughts. We will figure out a way to notify slashed vNode via out mobile application.

The current slashing rule only force Node out of committee. The staking-amount and reward which node received in that epoch will remain intact. We assume that all our users are trying to contribute to the system. When something go wrong, node get slashed, is a kind of notification to our users their nodes are not working properly


Yes, force to unstake is the only current penalty for slashing solution. So get slashed means node will be force to unstake


Update 9 Nov - 15 Nov


  • Unittest multiple instructions in one Beacon Block (Swap, Unstake, Assign, Random, Snapshot random list, Stop Auto Stake)
  • Review Stop Auto Stake and Unstake metadata and instruction. These instructions will be included in blockchain whenever they can change Incognito Chain state.
  • Integrate Slashing with New Staking Flow
  • Sync Testnet 2, all shard and beacon, (full verification) with New Staking Flow code
  • Sync Mainnet, beacon (full verification) with New Staking Flow code

Hey @hungngo,

I examine the code for a while. I see “autostake” properties in the response of “getbeaconbeststatedetail” RPC method. Some of them are true, others are false. What is the exact usage of “autostake”? Is there any relation with the committee?


  • autostake == true means your node will automatically get into candidate list once you finish your role as committee.
  • autostake == false means after you finish your role as committee, you will be completely out of Incognito Chain (no longer hold any role) and your staking will also be returned.

At this time, there’s no force unstake action or unstake rpc in Mainnet. This mode is in development and testing phase. Only stop auto stake action and stop auto stake rpc.


@hungngo It would be very beneficial to have the notification feature put in place prior to the slash/auto unstake feature takes place. So the community members hosting vNodes and pNodes can make sure their validators are operating as they expected (solid internet connection, bandwidth, etc.). I also think that community members are trying to contribute, but what I dont want to see is a large number of validators get slashed as the new update goes live because of misconfiguration…

For example, if you look back at the info on previous post there was misinformation on whether an ETH client was needed, and it was shown that it was to validate un/shield transactions, but there are several people who do not have an eth client running as they didn’t think it was needed.

I think it is also possible that some people using WiFi connections could have more unstable connections than they realize and would only realize this if there was some sort of notification that they were getting slashed.

These are just two possible things I can think of off top of my head, and it would be beneficial to the community to get these notifications prior to the full release of the dynamic committee being released, so they can make adjustments and fix their setups without being auto unstaked.

Going to cc @Peter on here, as I think this could really fall into a community experience realm


hey @doc, thanks for this. we released a topic earlier today that gives a general overview of the release plan, briefly mentioning validator support for the transition. would be great to hear your thoughts on how best to structure that!

to all validators reading this – please feel free to share your ideas here:


Your concern came cross our mind as well. We believe that our community is trying to help. The team will show the data of how vNodes and pNodes are working to all users, before any slashing in enable.


Update 30 Nov 2020


  • QC test and stress test on Staking Flow V2 features.
  • Merge code from development branch, resolve all conflicts and local test.
  • Code look cleaner, easy to read, and maintain
  • Dynamic-committee-size features are added into the team’s tasks. We drew some business process flow and tried to find our the bad cases.


  • QC will continue testing Staking Flow V2. At the end of first week of Dec, we will try to put this on Testnet
  • Complete Dynamic-committee-size business flow and move on the implementation spec

UPDATE 13 DEC 2020

These two weeks, we make a lot of progress. We expect to finalize code base for staking flow V2 at the end of November. However, merge code from development branch requires QC to test from the beginning. And also, we decide a good strategy for the community to change from current version to slashing version. All the code, business rules are almost finalized. Last but not least, thanks @trungtin2qn1, @khanhj, @dungtran for your hard work.

As planned, we are try to launch Staking Flow V2 + Slashing at the end of this month.

The team moved into new features, Dynamic Committee Size feature.

  1. Staking Flow V2 + Slashing Feature
  • Merge code Slashing to Staking Flow V2
  • QC business rules and stress test on Staking Flow V2 (which are finalized for team leaders’ review)
  • Codebase and strategy to change from Staking Flow v1 to Staking Flow V2 + Slashing. After nodes pull the Staking Flow V2 + Slashing code, nodes will run as Staking Flow V1 mode for a certain amount of time. During this time, as the community mentioned, we also record how many signatures one node contribute to the Chain. Then it switch to Staking Flow V2 + Slashing mode.

In progress:

  • QC business rules and stress test on Staking Flow V2 + Slashing.
  • Team leaders code review
  • Continuously conduct test in changing from Staking Flow v1 to Staking Flow V2 + Slashing
  1. Dynamic Committee Size features:


  • Elicit ambiguous requirements from Research Document.
  • Document: Process Business Flow Diagram, Class Diagram, User Story

In Progress:

  • Implement Swap rules in Dynamic Committee Size features