Forget What You Know About Consensus: This is The Quorum

Why Consensus Matters

Consensus mechanisms form the backbone of blockchain networks. They are the foundation for secure, decentralised operations. Traditional Proof of Work (PoW) has long been the cornerstone of achieving consensus and securing networks. But what if we could separate consensus from PoW and create a decentralised system that secures the network while leaving miners free to focus on directing computational power towards meaningful tasks?

In the Qubic network, the Quorum combines Byzantine Fault Tolerance (BFT) with a quorum consensus algorithm to create a secure and scalable consensus mechanism. Qubic separates its Useful Proof of Work (UPoW) model from the consensus process, bringing forth a fault-tolerant and highly decentralised architecture that is innovative and efficient.

What is a Quorum? 

In distributed computing, a quorum refers to the minimum number of participants required to achieve consensus in a system. This ensures that decisions are reliable and representative, even if some nodes fail or act maliciously. In Qubic, the Quorum is made up of 451 out of 676 Computors, following Byzantine Fault Tolerance (BFT) principles to maintain security and fault tolerance.

The Quorum Consensus Algorithm

The Quorum relies on a combination of Quorum Consensus algorithms and BFT principles to achieve security, scalability, and efficiency. The Quorum builds on the principles of Byzantine Fault Tolerance, as defined by Lamport et al., and the broader vision of decentralised trust frameworks articulated by Nick Szabo. By combining cryptographic validation with quorum-based decision-making, the Quorum achieves secure, trustless consensus for computational and network integrity

Key Features of the Quorum Consensus Algorithm:

• Decentralised Decision-Making: Quorum relies on a distributed network of Computors that validate and vote on computational tasks, ensuring resilience and fault tolerance.

• Byzantine Fault Tolerance (BFT): The system can withstand up to one-third of its nodes acting maliciously, maintaining integrity and trust even in adverse conditions.

• High Participation Requirements: With 676 Computors in the network, a quorum of 451 is required to achieve consensus, ensuring a high level of security.

• Separation of Concerns: Unlike traditional PoW systems, consensus is managed independently by Computors, freeing mining power to focus on meaningful AI tasks through uPoW.

This separation between consensus and mining ensures that Quorum achieves high efficiency while aligning computational resources with impactful goals.

The algorithm is designed for efficiency and scalability, enabling the network to function smoothly even under heavy loads or during network disruptions.

Roles in the Quorum Ecosystem

Computors: The Backbone of the Quorum Network

Performing Computational Tasks:

• Computors execute a variety of computational tasks, including validating transactions, executing smart contracts, and processing workloads within Qubic’s Useful Proof of Work (uPoW) framework.

• These tasks ensure that the network operates efficiently and that computational resources are used productively, supporting AI initiatives like Aigarth.

Participating in Voting for Consensus:

• Computors individually verify the output of computation tasks and participate in a secure voting process to achieve consensus.

• During each tick (a single consensus round), Computors vote on the validity of transactions, ensuring agreement across the network before committing results to the blockchain.

• Quorum rules require at least 451 out of 676 Computors to agree, aligning with Byzantine Fault Tolerance (BFT) standards to handle faulty or malicious nodes.

Ensuring Network Security and Integrity:

• By validating results and participating in quorum-based consensus, Computors protect the network against errors and attacks, maintaining trust in the system.

• They are critical for redundancy, ensuring that the network remains operational even if some Computors fail or behave maliciously.

Earning Rewards:

• Computors are incentivised with QUBIC coins in relation to the contribution they make to the network. Rewards are distributed for validating computational tasks, executing smart contract, achieving consensus, and ensuring network stability.

Key Role in Decentralised AI:

• Computors don’t just secure the blockchain; they also validate computational results for tasks like training artificial neural networks (ANNs) for Aigarth, bridging the gap between blockchain and Artificial General Intelligence (AGI).

Miners: Powering Useful Proof of Work

Miners, although not part of the quorum consensus model, provide the computational resources via Qubic’s Useful Proof of Work model. These resources enable AI training and other meaningful tasks, which are validated by Computors to ensure correctness. Together, miners and Computors form a collaborative ecosystem that fuels the network’s decentralised artificial intelligence goals.

Arbitrator: The Governance Safeguard

The Arbitrator oversees network integrity, replacing faulty Computors and resolving disputes. Qubic ensures decentralisation by allowing the Arbitrator’s decisions to be overridden by a supermajority of Computors (451 out of 676) should they suspect the Arbitrator has ‘gone rogue’. This balance strengthens the network’s security while maintaining trust.

Smart Contract Speed: Powered by The Quorum

The speed and efficiency of smart contract execution are critical for decentralised applications, and Qubic’s quorum consensus mechanism delivers on both fronts. While deeper technical details will be explored in upcoming posts dedicated to Qubic’s bare metal architecture and smart contracts, this section primarily focuses on how the quorum consensus mechanism itself contributes to high-speed smart contract execution.

The Quorum’s Role in Accelerating Smart Contracts:

1. Sub-Second Finality Through Quorum Consensus:
   Quorum's Byzantine Fault Tolerance (BFT) enables consensus to be achieved quickly by requiring agreement from 451 out of 676 Computors. This fast, fault-tolerant decision-making ensures that smart contract states are validated and finalised in under a second, paving the way for high-frequency, reliable contract execution.

2. Efficient Parallel Validation:
   Within the Quorum, computational workloads - including smart contract validations - are distributed across multiple Computors. This parallelisation ensures that even complex contracts are processed rapidly without compromising accuracy or security.

3. Optimised Communication During Consensus:
   The Quorum uses an efficient communication model to propagate votes and transaction data rapidly across Computors. By reducing latency in this critical step, the Quorum ensures that the entire contract execution process - from submission to finalisation - happens seamlessly.

4. Built on a High-Performance Foundation:
   The Quorum’s capabilities are supported by Qubic’s bare-metal deployment, which reduces latency and maximises computational efficiency. Furthermore, the use of native execution - directly running smart contracts without virtual machine overhead - ensures that the consensus process is tightly integrated with the blockchain’s smart contract architecture. These features work together to deliver unmatched speed and reliability.

Why It Matters:
The Quorum’s unique architecture ensures that Qubic’s smart contracts can support real-world use cases that demand both speed and scalability. For example:

• Real-Time Applications: The Quorum's speed makes it ideal for high-frequency trading, microtransactions, and automated supply chain logistics.

• AI Integration: By supporting fast execution cycles, Quorum complements Qubic's Useful Proof of Work (uPoW) model, which involves the validation of AI training and other computationally intensive tasks.

Why The Quorum Sets a New Standard

Whereas most blockchain networks use consensus mechanisms for transaction validation, the Quorum takes it a step further. Designed not only to secure the network but also to enable meaningful work, such as the training of decentralised AI, its unique combination of BFT and quorum consensus ensures that it is resilient, efficient, and scalable, setting it apart from other consensus frameworks in the blockchain space.

Looking Ahead: The Foundation of The Quorum's Performance

Unlike traditional blockchains that rely on virtual machines or operating systems, Qubic interacts directly with hardware to minimise latency and maximise performance. This foundation enables the Quorum to validate transactions and execute smart contracts at high speeds.

In our next Forget What You Know post, we’ll explore Qubic’s bare metal architecture and discuss how this approach sets Qubic apart as a high-performance, next-generation blockchain.

Call to Action

Forget what you thought you knew about consensus. The Quorum is reshapng what’s possible in blockchain and decentralised AI. By combining Byzantine Fault Tolerance with a quorum-based model, Qubic has created a system that not only secures the network but also drives meaningful progress in AI development.

Explore the future of consensus:

• Join the discussion on Discord and Telegram.

• Join the Qubic network to become a Computor, miner, or innovator.

What do you think about the Quorum’s approach to decentralised AI and blockchain? Share your thoughts and join the conversation.