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A Comparative Analysis Of Proof-of-Authority Consensus Algorithms: Aura vs Clique

Published November 13, 2023 9:53 AM
Alisha Bains
Published November 13, 2023 9:53 AM

Key Takeaways

  • Aura and Clique are two well-known PoA consensus algorithms with distinct characteristics, applications, and consequences for blockchain networks.
  • Aura emphasizes Byzantine Fault Tolerance (BFT) for security, while Clique prioritizes simplicity and decentralization.
  • Aura is suitable for enterprise-level blockchain applications requiring regulation and permissioned environments, emphasizing security through BFT.
  • Clique, with its decentralized and simple consensus process, is ideal for applications valuing decentralization in known-and-trusted participant networks or consortium blockchains.

The consensus algorithm choice is crucial in the changing world of blockchain technology since it guarantees the security, scalability, and general functioning of the network.

As a consensus mechanism, proof-of-authority (PoA) is distinct from resource-efficient proof-of-stake (PoS) algorithms and energy-intensive proof-of-work (PoW) algorithms.

This article compares and contrasts Aura and Clique, two well-known PoA consensus algorithms, highlighting their unique characteristics, applications, and blockchain network consequences.

What Is Proof-Of-Authority In Blockchain?

Prior to exploring the comparison, it is important to understand what proof-of-authority is all about. PoA depends on the identification and authority of participants, in contrast to PoW, where participants compete to solve challenging mathematical problems, or PoS, where validators are selected according to the quantity of cryptocurrency they own.

In PoA, nodes — also known as validators — are chosen according to their reputation, which is determined by an identity that has been pre-approved and verified. With this architecture, resource-intensive tasks are no longer necessary, and network security is improved.

Aura: Unveiling the Byzantine Fault Tolerance

The PoA consensus method known as “Authority Round,” or “Aura,” was created especially for the Ethereum network. By using the Byzantine Fault Tolerance (BFT) technique, it attempts to reduce the hazards brought about by rogue nodes or actors within the network.

Consensus ProcessFollowed By Aura

In Aura, a set of approved nodes rotates in a round-robin manner to propose and validate blocks as part of the consensus process. Because of the algorithm’s deterministic architecture, every authorized node is given an equal chance to contribute to the generation of new blocks. This improves the consensus process’s fairness and adds to the stability of the network.

Use-Cases Of Aura

Enterprise-level blockchain applications that require a regulated and permissioned environment are a good fit for Aura. It is resistant to Byzantine failures thanks to its BFT mechanism, which guarantees a high degree of security. 

For situations where the consensus method needs to resist possible malicious assaults or node failures without jeopardizing the integrity of the blockchain, this makes it especially appropriate.

Advantages Of Aura

  • Scalability: Scalability is facilitated by Aura’s deterministic nature, which makes block validation and propagation effective.
  • Security: By guaranteeing consensus even in the presence of malevolent nodes, the BFT mechanism improves security.

Clique: Decentralization And Simplicity

Another PoA consensus algorithm that runs on the Ethereum network is called Clique. Compared to Aura, it adopts a slightly different strategy that places more emphasis on decentralization and design simplicity.

Consensus Process Followed By Clique

A group of approved nodes in Clique, referred to as sealers, take part in the consensus process. But unlike Aura, which uses a round-robin system, Clique uses an open and simple voting system. 

Sealers put forth blocks, and a majority agreement is used to reach a consensus. Because of its simplicity, Clique is a desirable choice in situations where a simpler consensus procedure is desired.

Use-Cases Of Clique

Applications on the blockchain that value decentralization and preserve a permissioned network are best suited for Clique. It is appropriate for use cases where striking a balance between simplicity and security is essential due to its straightforward consensus procedure. This covers situations like known-and-trusted participant private networks or consortium blockchains.

Advantage Of Clique

  • Decentralization: By permitting several sealers to participate, Clique attains a certain degree of decentralization and enhances network resilience.
  • Simplicity: In situations where minimizing complexity is necessary, the simple consensus procedure is ideal.

Comparative Analysis Of Aura Vs. Clique



  • Uses a set of validators chosen by a governance mechanism.
  • Validators are frequently chosen based on their identity, reputation, or level of network involvement.


  • Has a specified fixed set of authority (signers).
  • There is no dynamic governance system in place to choose validators.

Validator Set Dynamics


  • Supports dynamic membership, allowing the addition or removal of validators over time.
  • Validators are often chosen based on some form of reputation or identity.


  • Static validator set, and changes require a hard fork.
  • Validators are typically known entities within a closed or consortium network.

Block Creation


  • Makes use of a round-robin system to create blocks, guaranteeing that validators participate equally.
  • Every round, a proposer is selected, and more people confirm the suggested block.


  • Uses a straightforward system in which authorities alternately suggest blocks.
  • There is no specific block validation phase; blocks are accepted if they are put forth by legitimate authorities.



  • Relies on the assumption that the majority of validators are honest.
  • If a majority is malicious, they could potentially control the network.


  • Vulnerable to attacks if a majority of authorities collude.
  • Security relies on the assumption that a significant portion of authorities are honest.



  • Faster finality due to the round-robin block creation process.
  • Generally quicker confirmation of transactions.


  • Finality depends on the block confirmation time, which can be slower compared to Aura.

Network Overhead


  • May have higher network overhead due to dynamic validator set changes.


  • Typically lower network overhead since the validator set is fixed.


The choice of consensus algorithm is crucial in the dynamic field of blockchain technology since it determines how a network behaves. Aura and Clique are compared to show off their unique qualities, benefits, and applicability.

With its BFT method, Aura stresses security and scalability, whereas Clique prioritizes simplicity and decentralization through its inclusive voting process. The decision between the two comes down to the particular needs of the blockchain application, be it a decentralized network looking for simplicity and inclusivity or an enterprise-level project requiring increased security.

The investigation of various consensus algorithms, like Aura and Clique, opens up new possibilities for customized solutions in a variety of use cases as blockchain technology continues to advance.


What is proof-of-authority consensus method?
Proof-of-Authority (PoA) is a consensus mechanism in blockchain where nodes (validators) are chosen based on pre-approved and verified identities, eliminating the need for resource-intensive tasks. It enhances network security and scalability.

How does Aura’s consensus process work?
Aura employs the Authority Round mechanism, utilizing Byzantine Fault Tolerance (BFT). A set of approved nodes proposes and validates blocks in a round-robin manner, ensuring equal participation and stability in the consensus process.

What are the uses of Aura?

Aura is suitable for enterprise-level blockchain applications requiring regulation and permissioned environments. It is resistant to Byzantine failures, making it appropriate for scenarios where security is crucial.

How does Clique differ from Aura in the consensus process?
Clique, another PoA algorithm, uses a simple voting system for consensus. Approved nodes, known as sealers, put forth blocks, and a majority agreement is used to reach consensus. It emphasizes decentralization and simplicity compared to Aura’s round-robin approach.

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