consensus
  • README
  • Blockchain Consensus Encyclopedia Infographic
  • CONTRIBUTING
  • Introduction
  • Blockchain Consensus?
  • Glossary
  • Categorizing consensus
  • Chain-based Proof of Work
    • Proof of Work (PoW)
    • Proof of Meaningful Work (PoMW)
    • Hybrid Proof of Work (HPoW)
    • Proof of Work time (PoWT)
    • Delayed Proof of Work (dPoW)
    • Proof of Edit Distance
    • ePoW: equitable chance and energy-saving.
    • Semi-Synchronous Proof of Work (SSPoW)
  • Chain-based Proof of Stake
    • Delegated Proof-of-Contribution (DPoC)
    • Secure Proof of Stake (SPoS)
    • Hybrid PBFT/Aurand
    • Proof of Stake (PoS)
    • Delegated Proof of Stake (DPoS)
    • Proof of Stake Time (PoST)
    • Proof of stake Boo (PoS Boo)
    • High Interest Proof of Stake (HiPoS)
    • Asset PoS (APoS )
    • Traditional Proof of Stake / Tiered Proof Of Stake (TPOS)
    • Casper the Friendly Finality Gadget (FFG)
    • Correct By Construction (CBC) Casper
    • Variable Delayed Proof of Stake (vDPOS)
    • Proof of Stake Velocity
    • Magi's Proof of Stake (mPoS)
    • Leased Proof of Stake (LPoS)
    • Delegated Proof of Importance (DPoI)
    • Leasing Proof of Stake (PoS/LPoS)
  • Chain-based Proof of Capacity/Space
    • Proof of Process
    • Proof of capacity (PoC)
    • Proof of Signature (PoSign)
    • Proof of Retrievability (POR)
    • Proof of Location
    • Proof of Reputation (PoR)
    • Proof of Proof (PoP)
    • Proof of History
    • Proof of Existence
    • Proof of Research (DPoR)
    • Proof of Activity
    • Proof of Weight (PoWeight)
    • Proof of Zero (PoZ)
    • Proof of Importance
    • Proof of Care (PoC)
    • Raft
    • Proof of Value (PoV)
    • Proof of Participation (PoP)
    • Proof of Believability
    • Proof of Stake (POS) / Proof of Presence (PoP)
    • Proof of Ownership
    • Proof of Quality (PoQ)
    • Proof of Space (PoC)
  • Chain-based Hybrid models
    • GRANDPA
    • Proof of authority (PoA)
    • Ethereum Proof of Authority
    • Limited Confidence Proof-of-Activity (LCPoA)
    • Proof of Work (PoW) / Nexus Proof of State (nPoS) or Nexus Proof of Holding (nPOH)
    • Proof of Activity
    • Proof of Work (PoW) / Proof of Stake (PoS) / Proof Of Care (PoC)
    • Proof of work (PoW) / High Interest Proof of Stake (HiPoS)
    • Proof of Work (PoW) / PoM / PoSII
  • Chain-based Proof of Burn
    • Proof of Processed Payments (PoPP)
    • Proof of Burn (PoB)
    • Proof of Time
    • Proof of Stake (PoS) / Proof of Disintegration (PoD)
  • Chain-based Trusted computing algorithms
    • Proof of Elapsed Time (PoET)
  • Chain-based PBFT and BFT-based Proof of Stake
    • leaderless BFT dual ledger architecture
    • Albatross
    • asynchronous BFT protocol
    • BFTree
    • Byzantine Fault Tolerance (BFT)
    • Delegated Byzantine Fault Tolerance
    • Federated Byzantine Agreement
    • HotStuff
    • LibraBFT
    • Modified Federated Byzantine Agreement (mFBA)
    • Ouroboros
    • Practical Byzantine Fault Tolerance
  • Chain-based others
    • Proof of Trust (PoT)
    • Proof of Devotion
    • Snowglobe
    • Avalanche
    • Serialization of Proof-of-work Events (Spectre)
    • Scrypt-adaptive-N (ASIC resistant)
  • Chain-based DAG
    • BlockFlow
    • Direct Acyclic Graph Tangle (DAG)
    • Hashgraph
    • Block-lattice - Directed Acyclic Graphs (DAGs)
  • Magi's proof-of-work (mPoW)
  • Common Attacks
  • Performance indicators
  • ThresholdRelay
  • Holochain
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  • Pros
  • Attacks and Mitigation
  1. Chain-based Trusted computing algorithms

Proof of Elapsed Time (PoET)

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Last updated 6 years ago

PoET is a consensus mechanism algorithm that is often used on the permissioned blockchain networks to decide the mining rights or the block winners on the network. Permissioned blockchain networks are those which require any prospective participant to identify themselves before they are allowed to join. Based on the principle of a fair lottery system where every single node is equally likely to be a winner, the PoET mechanism is based on spreading the chances of a winning fairly across the largest possible number of network participants.

The timer is different for each node. Every participant in the network is assigned a random amount of time to wait, and the first participant to finish waiting gets to commit the next block to the blockchain. Similar to pulling straws, but this time, the shortest stem in the stack wins the lottery.

Used in

  • Resource-Efficient Mining (REM) provides an economic analysis to show that a miner’s revenue source originates from useful work, and not farming chips.

  • Solve BFT Validating Nodes limitation and required intel’s SGX. PoET uses a random leader election model or a lottery based election model based on SGX, where the protocol randomly selects the next leader to finalize the block. Every validator requests a wait time from an enclave (a trusted function).

    • The validator with the shortest wait time for a particular transaction block is elected the leader.

    • The BlockPublisher is responsible for creating candidate blocks to extend the current chain. He takes direction from the consensus algorithm for when to create a block and when to publish a block. He creates, Finalizes, Signs Block and broadcast it

    • Block Validators check block

    • Block is created on top of blockchain.

Pros

  • Node will rest, so more energy efficient

    Cons

  • Trust Intel, require dedicated hardware

    Read more

Attacks and Mitigation

Breaking a single piece of trusted hardware enables the attacker to always win the lottery. Both Sawtooth and REM argue that a statistical analysis of newly minted blocks suffices to detect whether a chip can be compromised. Second, the stale chip problem highlights that it is advantageous to collect chips as this increases the probability of minting a new block (i.e., every new chips is an additional lottery ticket).

Hyperledger Sawtooth