Consensus Mechanism: Succinct Attestation
The Dusk consensus protocol, called succinct attestation (SA), is a permission-less, committee-based proof-of-stake consensus protocol run by all stakers, known as provisioners, which are responsible for generating, validating, and ratifying new blocks (Dusk) . This innovative mechanism is specifically designed to meet the demanding requirements of regulated financial markets.
Participant Requirements
To be eligible to participate in consensus, participants must have a pre-configured amount of DUSK locked as a stake (referred to as a Provisioner) and have a stake with a maturity of at least two epochs (referred to as an Eligible Provisioner) (OneKey) .
Core Mechanism: Deterministic Sortition
Random but Stake-Weighted Selection
Participation goes in turns, with provisioners being pseudo-randomly selected for each phase of the consensus through the deterministic sortition algorithm, which extracts provisioners in a non-interactive way based on their stakes: the higher the stake, the more the provisioner gets extracted (Dusk) .
Committee Formation
A committee is a subset of Eligible Provisioners, selected through a process called Deterministic Sortition (OneKey) . The deterministic sortition algorithm is used to select the block generator of the Proposal step and the members of the voting committees of the validation and ratification steps, taking a list of provisioners and a number of voting credits to assign to the extracted provisioners (Dusk) .
Three-Phase Consensus Process
Each consensus round proceeds through three distinct phases:
Phase 1: Proposal
In this step, a randomly-extracted provisioner is appointed to generate a new candidate block to add to the ledger, and other provisioners wait for the candidate block produced by the generator (Dusk) . Each provisioner node first executes the deterministic sortition algorithm to extract the block generator, and if the node is selected, it creates a new candidate block, signs it and broadcasts it (Dusk) .
Phase 2: Validation
In this step, the candidate block produced or received in the proposal step is validated by a committee of randomly chosen provisioners who verify the candidate's validity and then cast their vote accordingly (Dusk) . The validation committee is generated by assigning 64 credits among all provisioners, except the block generator (which can thus not vote for its own block) (Dusk) .
The main purpose of the validation step is to agree on whether a candidate block has been produced and if it is a valid new tip of the blockchain (Dusk) .
Phase 3: Ratification
Another committee confirms the validation outcome and finalizes the block (Coinspeaker) . This final phase ensures that the validation results are confirmed by an independent committee before the block is permanently added to the blockchain.
Iteration System and Finality
Multiple Iterations Per Round
If a candidate is produced in the Proposal step and a supermajority of votes is reached in favor of the block, the candidate is added to the blockchain with the result of the iteration certified with an attestation containing all the digitally-signed votes of the committee members that reached agreement on the block (Dusk) .
If the iteration fails, a new one is executed with a new candidate and a different set of provisioners running the protocol, with a maximum of 255 iterations run in a single round, and the last one producing an empty emergency block, which ensures no round ends without a block (Dusk) .
Consensus States and Fork Handling
The mechanism automatically resolves forks as soon as all conflicting blocks are received by all nodes (Dusk) . Blocks in the local chain can exist in different consensus states, determining whether they can be replaced by lower-iteration blocks or not.
Performance Characteristics
Statistical Finality
SA provides statistical finality guarantees, which is a finality guarantee achieved through the accumulation of blocks over time, such that the probability of a block being reversed decreases exponentially as more blocks are added on top of it (OneKey) .
Efficiency Advantages
The protocol operates in rounds, each generating a new block via a series of validation phases involving the creation of a candidate block, two rounds of voting on its validity by selected committees, and an agreement phase where the block is accepted if it garners enough votes (LinkedIn) .
The committee-based approach provides significant advantages: committee-based PoS mechanisms often have faster block times and lower overhead than their non-committee counterparts (OneKey) , making Succinct Attestation particularly well-suited for financial applications requiring fast settlement and deterministic finality.
Technical Implementation
The implementation of SA consists of two main tokio-rs tasks, the Main_Loop and Agreement_Loop, which communicate with external components through message queues/channels (OneKey) . This architecture ensures efficient coordination between block proposal, validation, and ratification processes while maintaining the security guarantees required for financial infrastructure.
Why It Matters for Finance
The Succinct Attestation consensus mechanism is an innovative and fast Proof-of-Stake based consensus with settlement finality guarantees, which is a crucial requirement for financial use cases (Coindar) . The combination of speed, deterministic finality, and security makes it ideal for regulated financial applications where transaction irreversibility and rapid settlement are essential requirements.
