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Dynamic Committees

In Assembly, smart contract validators form committees for each smart contract chain. These committees are responsible for running each smart contract and corroborating they all obtain the same result.

Open Committees

Smart contract developers are free to select the members in their chain's committee according to any criteria they choose. However, the simplest, most decentralized, permissionless, secure, and reliable way to select the members in your committee is using the open committee selection process. This process periodically updates committees to establish the validators with the highest trust score possible on each seat.

To use dynamic open committees, you simply need to place a special opening message in the marketplace smart contract. This message must contain your smart contract chain's security and reliability requirements, which Assembly will transform with its score function. The protocol will later use the aggregated score to match your requirements and the available validators.

Keep in mind that Assembly is an open marketplace, so once the protocol has selected the potential validators, they will still be able to choose if they accept or reject the seat based on fees offered by your smart contract chain. You may also choose to assign seats in the committee to nodes of your choice, forming what is known as semi-closed or semi-open committees.

Open Committee Updates

Assembly allows for dynamic committee updates. This increases the reliability, security, and liveness of the smart contract chains while also empowering DAOs to directly influence the infrastructure responsible for executing their contract.

Validators are allowed to join and leave committees if any of the following conditions happen:

  1. Resignation from the committee seat: A node announces that it wants to leave the committee under certain penalty conditions.
  2. Removed by the chain's governance: A chain’s governance enforces the removal of certain nodes from the committee.
  3. Removed by the root committee: An unreliable node is forcibly removed from the committee.

Keep in mind that a node will only be removed when misbehavior has been detected and is verifiable. The Root committee will initiate the process to forcibly remove it from the committee without affecting the continuous execution of the smart contract chain.

Misbehavior

Assembly may force a validator to leave a committee if misbehavior is reported (or detected) and verified. This purges unreliable nodes and "lazy participants" (any node which aims to collect rewards without doing the necessary calculations for the smart contract), making the chains more reliable. Assembly will decrease the trust and reliability scores of any node that is forcibly removed from a committee and possibly slash their stake. Honest nodes are encouraged to report any misbehavior they detect as Assembly will reward them with part of the slashed stake.

The Root committee

The root committee oversees the whole of Assembly. It is in charge, amongst other things, of dynamically allocating seats in all open committees. It is critical to the security of IOTA smart contracts on Assembly, so this committee's seats will only be granted to the most trustworthy nodes. It is periodically updated to include only the most trustworthy nodes, and any node can participate in the selection process. Only the validators with the highest trust score will be able to compete for these highly coveted seats. This rotation ensures the root committee is secure, decentralized, and reliable.

Joining the Root committee

If you want to participate in the Root Committee as a validator, you will need to prepare a special application message within an application time window. This message will be signed and timestamped, and the validity of the timestamps assured by the Tangle. All the nodes who have access to the trust score function will then come to a consensus on the selected members of the core Assembly.

The root committee will be periodically updated to prevent centralization and increase reliability. As only the nodes with the highest trust score will be considered for these highly coveted seats, it is secured against overtaking.