Consensus mechanism history which consensus mechanisms do you know

Behind every great cryptocurrency, there is a great consensus algorithm. No consensus algorithm is perfect, but they all have their own advantages. In the field of encryption, consensus algorithms exist to prevent double spending. The following is a quick overview of some of the most popular consensus algorithms to date, from blockchain to DAG and everything in between.

Proof of Work (PoW) 

Pros: We know it is effective

Disadvantage: slow throughput

Proof of Work is the first blockchain consensus algorithm. Designed by Satoshi Nakamoto for the Bitcoin blockchain, we would like to thank PoW, which contributes to the large-scale mining operations and power consumption we see all over the world. We know it is feasible (for many other consensus algorithms, we can say more), but at this stage in this field, it is beginning to be considered a traditional technology. With so many new alternatives, it is difficult to understand why new blockchains will use PoW.

In PoW, miners create blocks by solving difficult and useless problems. PoW runs on the “longest chain wins” system. So assuming that most miners work on the same chain, the fastest growing is the longest and most trustworthy. Therefore, as long as more than 50% of the miners’ work is honest, Bitcoin is safe.

Proof of Stake (PoS) 

Consensus mechanism history which consensus mechanisms do you know

Advantages: more expensive attacks; more decentralization; energy efficiency

Disadvantages: There is no taboo in pledge

In PoS, blocks are not created by miners, but miners use their tokens to “bet” which blocks are valid. In the case of a fork, the mint spends their tokens to vote for which fork. Assuming that most people vote on the correct fork, validators who vote on the wrong fork will “lose their pledge” on the correct fork.

A common argument against proof of interest is the issue of “no taboo in pledge.” The problem is that since verifiers can support PoW forks with almost no computing power, they can vote on both sides of each fork that occurs. PoS forks may be more common than PoW, and some people worry that it will damage the credibility of this currency.

Delegated Proof of Stake (DPoS)-choose your own validator

Advantages: cheap transactions; scalable; high efficiency and energy saving

Disadvantage: Partially centralized

DPoS is the crystallization of Daniel Larimer’s wisdom, and is actually very different from PoS. In DPoS, token holders do not vote on the validity of the block itself, but instead vote to elect representatives to verify on their behalf. In the DPoS system, there are generally 21-100 elected representatives. The delegates shuffle the cards regularly and get orders to deliver their blocks. A small number of delegates can allow them to organize themselves effectively and create a designated time period for each delegate to publish their blocks. If representatives continue to miss their blocks or post invalid transactions, the pledger will vote to eliminate them and replace them with better representatives.

In DPoS, miners can collaborate to produce blocks instead of competing with each other as in PoW and PoS. By partially centralizing the creation of blocks, DPoS can run several orders of magnitude faster than most other consensus algorithms.

Proof of Authority (PoA) 

Advantages: high throughput; scalable

Disadvantage: centralized system

Proof-of-Authority (Proof-of-Authority) is a consensus algorithm in which transactions are verified by an approved account, a bit like the “administrator” of the system. These accounts are the authority for other nodes to obtain the truth. PoA has high throughput and is optimized for private networks. Due to the centralized nature of PoA, it is unlikely to see PoA running on the public chain.

Proof of Weight (PoWeight)

Advantages: customizable; extensible

Disadvantages: Incentive mechanism is a challenge

Proof of weight is a broad classification of consensus algorithms based on the Algorand consensus model. The general idea is that in PoS, the percentage of tokens a user owns in the network represents the probability that the user “discovers” the next block. In the PoWeight system, some other relatively weighted values ​​are used. Specific example: Filecoin’s Proof-of-Spacetime depends on how much IPFS data the user stores. Other systems may include some weights, such as proof of credibility.

Byzantine Fault Tolerance (BFT) 

Consensus mechanism history which consensus mechanisms do you know

Advantages: high throughput; low cost; scalable

Disadvantage: half trust

A classic problem is that distributed computing is usually explained by Byzantine generals. The problem is that several Byzantine generals and their respective armies surrounded a city. They must unanimously decide whether to attack. If some generals attack alone, their siege will end in tragedy. Generals are usually separated by a distance and must communicate by passing information. Some cryptocurrency protocols use certain versions of BFT to reach consensus, and each version has its own advantages and disadvantages:

Practical Byzantine Fault Tolerance (PBFT): The first solution to this problem is called Practical Byzantine Fault Tolerance. Used in Hyperledger Fabric, few (<20) pre-selected generals PBFT runs very efficiently. Advantages: high transaction throughput, disadvantages: centralization

Federal Byzantine Agreement (FBA): FBA is another method of solving the Byzantine generals problem, such as Stellar and Ripple . The general idea is that every Byzantine general is responsible for their own chain, because they establish the truth sorting message as soon as they come in. In Ripple, the generals (validators) are pre-selected by the Ripple Foundation. In Stellar, anyone can become a validator, so you can choose which validator to trust.

Directed Acyclic Graph (DAG)

Consensus mechanism history which consensus mechanisms do you know

Advantages: network scalability; low cost

Disadvantages: depends on implementation

DAG is a form of consensus. It does not use the blockchain data structure and mainly processes transactions asynchronously. In theory, the biggest advantage of DAG is unlimited transactions per second, but like other consensuses, DAG also has advantages and disadvantages.

Tangle : Tangle is the DAG consensus algorithm used by Iota. In order to send an Iota transaction, the user needs to verify the two previously received transactions. When more transactions are added to the Tangle, consensus strengthens the effectiveness of transactions. Because consensus is established through transactions, in theory, if someone can generate 1/3 of the transaction, he can convince other members of the network that his invalid transaction is valid. Until there is enough transaction volume to create 1/3 of the transaction volume becomes infeasible, Iota will “recheck” all network transactions on a centralized node called the “coordinator”. Iota said that the coordinator is like the training wheel of the system, once the Tangle is large enough, it will be removed.

Hashgraph : Hashgraph is a gossip protocol consensus developed by Leemon Baird. Nodes randomly share their known transactions with other nodes, so eventually all transactions are propagated to all nodes. Hashgraph is very fast (250,000+ transactions per second), but it cannot resist witch attacks. Therefore, Hashgraph for the private network is a good choice, but you will not soon see it in the Ethernet Square realization or Dispatch public network.

Block-lattice : Nano (previously known as Raiblocks) runs on the blockchain and is called Block-lattice. Block-lattice is a structure in which each user (address) has its own chain, only they can write to the chain, and everyone holds a copy of all chains. Each transaction is decomposed into a sending block on the sender chain and a receiving block on the receiver chain. Block-lattice seems too simple, but it is already running in the wild. This unique structure does open Block-lattice to some unique attack vectors, such as the Penny-spend attack, in which the attacker exaggerates the number of chains that a node must track by sending a negligible amount to a large number of empty wallets.

SPECTRE : Serialization of Proof-of-Work events: Confirmation of transactions through recursive elections. The more widely known name is SPECTRE. It is a proposed Bitcoin extension solution that uses a combination of PoW and DAG to reach a scalable consensus. In SPECTRE, blocks are directed to multiple parent nodes, not just one, so the network may process multiple blocks per second. Mining blocks that point to some parent blocks supports the validity of these blocks. Compared with PoW’s “longest chain win”, SPECTRE uses “a block with the most sub-elements to win”.

Proof of Capacity

In the capacity proof method, the answers to complex mathematical problems are stored in digital storage such as hard disks. The whole process is called drawing. When the storage device is filled with solutions to mathematical puzzles, users can use the storage device to generate blocks. The user who finds the solution the fastest has the opportunity to create a new block. Therefore, users with the highest storage capacity will have a higher chance of generating new blocks.

Proof of Elapsed Time (Proof of Elapsed Time)

The elapsed time proof process randomly and fairly determines the producer of the new block based on the time they wait. To this end, the mechanism provides a random waiting time for each user, and the user who has the earliest waiting time will generate a new block. This consensus mechanism will only work when the system can verify that no user can run multiple nodes and the waiting time is truly random.

Proof of Identity

The identity proof compares the user’s private key with the authorized identity. Basically, an identity certificate is a piece of encrypted evidence of a user’s private key, which is attached to a specific transaction in an encrypted manner. Any identified user in the blockchain network can create a data block, which can be presented to anyone in the network. The identity certificate ensures the integrity and authenticity of the created data. In addition, smart cities can use blockchain consensus mechanisms, such as proof of identity, to verify the identity of their citizens.

Proof of Activity

The activity proof mechanism is a combination of proof of work and proof of rights. In the activity proof, miners try to find solutions to puzzles and get rewards. However, the block created in the activity proof mechanism is a simple template, which mines the reward address and header information. Then use the header information to randomly select a group of verifiers to sign the block. Verifiers with larger stakes are more likely to be selected to sign new blocks. Once the selected verifier signs a new block, it becomes part of the network. If some verifier does not sign the block, it will be discarded and a new block will be used. The network fees generated during this process are distributed between the winning miners and validators.

 

Posted by:CoinYuppie,Reprinted with attribution to:https://coinyuppie.com/consensus-mechanism-history-which-consensus-mechanisms-do-you-know/
Coinyuppie is an open information publishing platform, all information provided is not related to the views and positions of coinyuppie, and does not constitute any investment and financial advice. Users are expected to carefully screen and prevent risks.

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