What Is Proof of Authority and How Does It Work?

What Is Proof of Authority and How Does It Work?

Proof of Authority is a consensus mechanism used in blockchain networks that focuses on reputation-based validators, making it more scalable and efficient than Proof of Work and Proof of Stake algorithms. PoA is well-suited for logistical applications and private blockchains, but its lack of decentralization has raised concerns within the cryptocurrency community. Nonetheless, PoA offers an interesting and emerging blockchain solution that is worth watching in the evolving landscape of cryptocurrency.


Since the first blockchain transaction on the Bitcoin network, the landscape of cryptocurrency has evolved significantly. New consensus mechanisms were proposed to improve the way consensus is reached within a blockchain system, in addition to the well-known Proof of Work (PoW) and Proof of Stake (PoS) algorithms.

Although the PoW algorithm used by Bitcoin is regarded as the most reliable and secure consensus mechanism, it is not very scalable. Due to its distributed network of nodes, which need to agree on the current states of the blockchain, Bitcoin and other PoW-based blockchains can only handle limited transactions per second (TPS). Before a new block of transactions can be confirmed, it needs to be verified and approved by the majority of network nodes. While this decentralized approach provides a secure and trustless economic system, it also limits Bitcoin's potential for large-scale use.

Compared to Bitcoin, PoS blockchains generally demonstrate better performance in terms of transactions per second. However, they have yet to solve the scalability issue. As a result, the Proof of Authority (PoA) consensus mechanism is now being implemented as a more efficient alternative. PoA is capable of performing a significantly larger number of transactions per second than PoW and PoS.

What Is Proof of Authority?

Gavin Wood, the former CTO and co-founder of Ethereum coined the term Proof of Authority (PoA) in 2017 as a practical and efficient solution for blockchain networks, particularly private ones.

Unlike other consensus algorithms, PoA validators stake their reputation rather than coins. This identity-based approach means that PoA blockchains are secured by validators arbitrarily chosen as trustworthy entities. With a limited number of block validators, PoA is highly scalable. Pre-approved participants act as moderators to verify blocks and transactions.

PoA is well-suited to logistical applications and has been praised as an effective solution for supply chain management. It allows companies to maintain their privacy while benefiting from blockchain technology. Microsoft Azure also utilizes PoA in their private network solutions, eliminating the need for a native currency like ether or mining.

PoA vs PoS

While PoS is a well-known consensus algorithm that is used in many blockchain networks, its decentralized nature is not always appropriate for certain businesses and corporations. As a modified version of PoS, PoA is gaining popularity because it uses identity instead of coins.

PoA's reputation-based approach makes it a suitable option for private blockchains that require high-performance networks. Since PoA systems rely on a limited number of validators who are pre-approved, the network can process transactions much faster than PoS-based blockchains.

Ensuring System Reliability in PoA

In the PoA consensus algorithm, certain conditions must be met to ensure the system's reliability. Validators are required to confirm their real identities, and becoming a validator requires a significant investment of money and reputation. This rigorous process reduces the risks of selecting untrustworthy validators and incentivizes a long-term commitment.

In addition, a standard for validator approval must be in place to ensure that all candidates are treated equally. The essence of the reputation mechanism is the certainty behind a validator's identity, which requires a strict and thorough selection process.

The selection process must be challenging to weed out bad actors and ensure the system's integrity and reliability. By ensuring that all validators go through the same procedure, the system's fairness and impartiality are guaranteed.

PoA’s Limitations

The PoA consensus algorithm is often criticized for lacking decentralization, which some say makes it nothing more than an attempt to improve centralized systems' efficiency. Despite its appeal to large corporations, there is some hesitancy surrounding PoA, particularly within the cryptocurrency community.

  1. The perception is that PoA foregoes decentralization, which makes it an attractive solution for centralized systems but raises concerns in the cryptocurrency scope.
  2. PoA systems allow for censorship and blacklisting, which questions its immutability aspects.
  3. The identities of PoA validators are visible to anyone, which could potentially lead to third-party manipulation and compromise the system from within.
  4. PoA sacrifices decentralization to achieve high throughput and scalability, which is highly valued within the cryptocurrency community.
  5. PoA presents a stark contrast from how blockchains have been functioning until now, making it an interesting but emerging blockchain solution, suitable for private blockchain applications.


While Proof of Authority may not be the most decentralized consensus algorithm, it does offer a practical and efficient solution for private blockchain networks. Its reputation-based approach provides a high level of scalability and performance, making it a suitable option for businesses and corporations that require high-throughput networks. However, the limitations of PoA, particularly its lack of decentralization, may raise concerns for those in the cryptocurrency community who prioritize immutability and trustlessness. Overall, Proof of Authority presents an interesting and emerging blockchain solution that is worth watching in the evolving landscape of cryptocurrency.

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