What is Proof of Elapsed Time (PoET)

Proof of Elapsed Time (PoET)

Proof of elapsed time is a consensus technique for the Ethereum blockchain that reduces resource and energy utilization while maintaining process efficiency using a fair merit system.

On a blockchain network, the algorithm decides who gets to mine coins and who wins a block using a procedurally chosen amount of time. The PoET algorithm creates accountability by guaranteeing that outside parties may verify lottery results by running a verified code in a secure environment.

  • A consensus mechanism called Proof of Elapsed Time (PoET), created by Intel Corporation, allows described blockchain networks to decide who will build the following block.
  • Every node in the PoET network has an equal opportunity to win, thanks to the system’s lottery-style distribution of winning odds.
  • Each node in the blockchain network receives a random wait time from the PoET algorithm; they must all go to sleep during that time.
  • The node that woke up first and won the block will be able to add a new block to the blockchain because it had the least wait time.
  • The PoET process is comparable to Bitcoin’s proof-of-work (PoW). Still, it uses less energy because it permits a node to go to sleep and perform other jobs for a predetermined period, improving network energy efficiency.
  • The PoET process is comparable to Bitcoin’s proof-of-work (PoW). Still, it uses fewer resources because it permits a node to go to sleep and perform other jobs for a predetermined time, improving network efficiency.

Further in this article, we will discuss the following: 

  • What is Proof of Elapsed Time?
  • How did it work?
  • How is PoET Different from PoW?
  • What Is Hyperledger Sawtooth?
  • Important Components of PoET?
  • How does PoET Algorithm Operates?
  • Advantages of PoET

What is Proof of Elapsed Time?

This consensus, often known as PoET, is anything but poetry! Most blockchain technologies, including Hyperledger Sawtooth, use the algorithm (in addition to PBFT). PoET chooses the node that will win the next block in a manner akin to a lottery. PoET was first implemented in Hyperledger Sawtooth in 2016–2017 by Intel. The “miners” must initially sign up for the network and receive a membership credential. Then, the nodes have to wait for a predetermined time after joining the network. Finally, before beginning to mine a new block into the blockchain, the miner must wait for the specified minimum length of time.

In PoET, the miner chooses to mine the blocks for that round. The mechanism often selects miners fairly and with a respectable amount of randomness. In addition, miners can “sleep” while waiting for their turn because it uses relatively little electricity.

Blockchain networks employ a consensus algorithm to confirm transactions and add new blocks. However, proof of elapsed time (PoET) is a consensus technique frequently used on public blockchain systems to select block winners or miners. Blockchain networks that require identification from potential participants are known as permission blockchain networks.

The PoET network consensus process must guarantee two essential components. First, it ensures that the networking devices choose a time arbitrarily and not one shorter so they can win. It also proves that the winner has passed the waiting period.

How did it work?

The PoET method distributes the odds of winning across the most feasible network members based on a fair lottery system where each node has an equal chance of being chosen.

Each participating node in the PoET network must wait for a predetermined amount of time; the first node to finish the waiting time successfully wins the new block. In the bitcoin blockchain, each node produces a randomized wait time and goes to sleep for that time. The peer network is broadcasted with the essential information by the one who wakes up first or with the least wait time and submits a new block to the blockchain. The subsequent block discovery follows the same procedure.

How is PoET Different from PoW?

The methodology is exactly the same as Bitcoin’s proof of work (PoW) consensus mechanism, but without significant energy consumption. In addition, it boosts the effectiveness of the network by enabling a node to sleep and move to other duties for a predetermined period.

Because one must provide a certificate to anyone who wants to join the network, proof of elapsed time does not encourage decentralization and openness the way proof of work does. Additional network requirements are also taken care of by running trustworthy code in a secure setting. It ensures that we execute the trusted code safely and cannot change any party. Additionally, it provides that the outcomes may be checked by users or other permitted parties, increasing the transparency of a stronger sense of belonging.

However, for the cryptocurrency market to continue to thrive, PoET must control the cost of the consensus process. Therefore, agile maintain proportionality to the benefit gained from the process.

What Is Hyperledger Sawtooth?

Similar to a blockchain, Hyperledger Sawtooth is a decentralized cryptocurrency created for business applications, including logistics and supply chains. However, it might also use it for time-consuming and error-prone corporate processes like inventory management and accounting.

  • An open-source corporate blockchain-as-a-service platform called Hyperledger Sawtooth allows users to run customized smart contracts without being familiar with the system’s internal architecture.
  • Companies like SAP, IBM, Intel, and the Linux Project support a broad-based blockchain development consortium called Hyperledger.
  • Numerous consensus techniques, such as Practical Byzantine Fault Tolerance (PBFT) and Proof of Elapsed Time, are supported by Hyperledger Sawtooth (PoET)

Important Components of PoET

The PoET network consensus procedure must ensure two essential elements. First, the process ensures that the participating nodes truly select a random time and do not select a shorter window on purpose to win. The method demonstrates that the winner has completed the waiting time.

Intel SGX

Two critical elements of the Proof of Elapsed Time are within the control of Intel SGX:

  • Highly specialized hardware can generate a certificate that makes the code appear reliable.
  • The trusted code executes in a safe environment. The remainder of the application cannot check out or make changes to the reserved and private storage area.

A network user can demonstrate to other consumers that he is using reliable and correct network code by utilizing the first point. Without this capability, the network cannot identify whether a participant is actually executing the PoET correctly. Furthermore, thanks to the second clause, a corrupt player cannot change PoET’s trustworthy code once you set it.

What is SGX?

Although SGX is an advanced software, at its core, it is essentially a set of CPU directives that applications can use to isolate specific, reliable code and data fragments. It gives programmers a secure environment to hide sensitive data or code from outside intervention or scrutiny.

Code that runs in a TEE utilizing SGX can produce a signed attestation that shows the code is initial in a trusted environment. So this can be done by a platform or application rooted in the processor. This feature substantially impacts PoET consensus functionality but also adds an implicit barrier to entry and limits its applicability. It is inaccessible to anyone, not even antagonistic persons, with access to a platform and the highest authentication to access its memory. Due to its possible security, embrace SGX as a security feature with great expectations.

How does PoET Algorithm Operates?

The time-lottery approach ensures that every network member has an equal opportunity to win the prize and add a new block to the network. The PoET controller updates the stopwatches on each participating node.

It ensures they can create a new block after their waiting period ends. When the node wakes up, we deliver the block and a cryptographic test to the PoET administrator for verification. First, pick the freshly proposed block if the controller accepts the newly proposed block by the first node to wake up. It begins the selection for a waiting time procedure. Let’s explicitly delineate the steps in the process.

Selection Method

Each participating node must first exchange its certificate generated by the Intel Software Guard Extension to add a new block to the network (SGX). After that, they are eligible to get a timer object.

The integers were assigned as a timer object using Intel’s RAND random number generator instruction (waiting countdown time). It generates values that are unpredictable and hard to distinguish. Each participant node’s time object has begun to operate at this point.

Creation Method

After the time object ends and the node awakes, it will be feasible for it to add a new block to the network. Then, using a hash method like SHA-256, the active node generates the hash of its block of transactions and sends it for review.

Advantages of PoET

Proof-of-work methods are substantially more effective when we use PoET. At the same time, it provides an excellent solution to the “Random Leader Prediction Phase” without requiring a significant investment of time, money, or the intricate incentive structures and staking processes necessary to demonstrate stake consensus.

Since PoET provides a beautiful private blockchain network consensus mechanism, it is the recommended consensus method for Hyperledger Sawtooth. In addition, it scales well and works as a “plug and play” simulation for testing Blockchains Sawtooth configurations.


PoET is an additional effort to provide Byzantine Fault Tolerance consensus procedures for distributed ledger systems. It makes use of SGX, which is a cutting-edge innovation in and of itself.

What transpires with SGX will significantly impact PoET’s ability to function as a durable consensus financial modeling. In addition, it’s an excellent tool for Hyperledger Sawtooth and is necessary for research and development on modular blockchain frameworks.

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