Homework on Consensus - Questions

Blockchain and Bitcoin 101
#4379

  1. What does it mean when we say that in blockchain, consensus determine the truth?
    When a transaction is about to enter the blockchain, the network decides whether the transaction holds true. Each player of the network is financially incentiviced to be honest which will lead to consensus.

  2. How is this different from how truth is determined in a central database?
    In central database a single authority can alter the truth to support their agenda. Also “consensus” could be reached by a handful of operators.

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#4380

1. What does it mean when we say that in blockchain, consensus determines the truth?

An entry in the blockchain network is verified by the network, either true or false.

2. How is this different from how truth is determined in a central database?

True or false is not determined by the entire network, it is determined by certain actors in the network which can be a single or multiple entities

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#4381

  1. All nodes should reach consensus before a transaction is verified. So that means that if a transaction is verified on the blockchain all nodes confirmed this as being true.

  2. it is not confirmed to be true by all parties involved in a central database.

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#4382

  1. Because it is a mechanism that determines whether the data are true or no

  2. Because it is distributed and not a single entity can add without the consensus agreement from network.

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#4383
  1. Blockchain consensus determines the truth by being verified on a network by multiple sources and companies. It becomes very difficult to cheat and lie about where things have come from because there are so many other companies or computers verifying transactions or products that when there is an anomaly it gets noticed and denied by others with financial incentives for everyone to tell the truth.
  2. This differs from a central database because its more of a network where everything is visible and traceable throughout many different companies or transactions rather that single database showing only one type of transaction or one company.
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#4384
  1. What does it mean when we say that in blockchain, consensus determines the truth? - in every transaction that is about to be listed in the blockchain, a validating decision from all the computers in the network is required. Participants to the blockchain are rewarded for signalling transactions that do not make sense, everybody in the network is rewarded to play by the rules.
  2. How is this different from how truth is determined in a central database? - blockchain validators are decentralized, it is necessary that all participants to the public ledger validate each of the transactions. in the central database, the name itself says centralized, decisions can be made by entities or individuals without the agreement of all the rest of the participants in the network.
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#4385

Many nodes in the blockchain are validating a transaction and all of them must come to a consensus that this transaction is good. If one transaction is false the nodes will not find a consensus and hence it will be rejected. Hence only if the network finds consensus = determines the truth. On top consensus is removing trust and is achieved through incentives. Meaning if you tell the truth you get incentivised - if you don’t tell the truth you get punished. Easy as that!

  1. How is this different from how truth is determined in a central database?
    Since the “database” is a decentralised network and all of the players (nodes) need to find an agreement (consensus) that determines the truth, it is very different from a central database. Whoever has the key, resp. access to the database can change it as he wish.
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#4386

Homework on Consensus - Answers

  1. Only when every part of the blockchain network agrees that the information which wants to get added is correct it will get included.

  2. We now have a system which rewards people for telling the truth. So we don’t have to trust anymore.

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#4387
  1. What does it mean when we say that in blockchain, consensus determines the truth?
    All sides from network agreed on what is true and what is not true. So an individual cannot cheat.

2.How is this different from how truth is determined in a central database?
One can change information as he like and others have to just belive/trust that what is written is true and actually it doesn’t need to be true.

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#4388

  1. All nodes in the network need to agree on a transaction. They need to reach a consensus.

  2. In a central database an individual can alter it’s information, which can’t be verified.

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#4389

  1. Consensus is the method or algorythm that provides a common and incentives based approval of transactions or data (ensuring that they happened, that they are correct and the data is not manipulated etc.). Therefore consensus is the approach to know or access the truth and in a way it is automatic not in a technical sense, but rather in the sense that for a public ledger, where consensus works to record and track the data - there really is no other option but to get to the truth.

  2. In a central database theoretically a consensus can be claimed to be used, however as it is usually not entirely public and equally traceable to all participants, it can be manipulated or adjusted by whoever has access to the database or to the authority that holds the key or master version of the database. The main difference is therefore the fact that in a central database there is one key authority determining the truth and there is no such central authoritative figure in blockchain.

3 Likes
#4390
  1. Consensus is the agreement between nodes for a transaction.
  2. There are fewer people involved in a central system which means that the truth can be bent whereas in this system we can be sure everything is true.
1 Like
#4391
  1. In blockchain, the phrase ‘consensus determines truth’ means that in a trustless system where we do not need to rely on one particular entity and “trust” them with opaqueness, we can have a distributed system where everyone keeps track of the record and is incentivized to tell the truth about the data on the blockchain. This is because the group consensus will reject a false addition to the blockchain due to incentives.
  2. This example of truth in blockchain is different than how truth is determined in a central database because truth on a blockchain works through a distributed system with no singular point of failure and where the provenance of a transaction can be trusted because information may not be modified on a blockchain, only added, therefore the data is immutable and safe as it is backed up in so many places.
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#4392

Consensus --> Acceptance of a transaction by the members of the network comps
The difference of Blockchain Consensus --> The members of the network are incentivized not to cheat whereas the administrator of the central database may cheat.

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#4393

Q1. What does it mean when we say that in blockchain consensus determines the truth?
A. All parties agree with the transaction and it is confirmed true by all parties. Once confirmed it then put on the blockchain forever. These parties have an incentive to tell the truth to get a transaction reward.

Q2. How is this different from how truth is determined in a central database?
A. With a central database the truth is determined only by the governing body that makes the decision, like an administrator on any kind of network.

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#4394
  1. By allowing a unanimous verification of transactions, it becomes very difficult for fraudulent or incorrect data to be transmitted between parties. This along with incentives aimed at nodes for the verification process encourages honesty with financial stimulus.
  2. This in contrast with a centralised database, creates a network of supply as opposed to the linear model we see in typical supply chains whereby data provided between suppliers is passed in in a chain rather than a web or network.
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#4395

  1. If all nodes agree or disagree a trasaction to be true; then consesus in gained and therefore removes the need for trust because it can be verified.

  2. In a central db no consesus in needed; it is trusted by whoever owns the db.

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#4396

  1. What does it mean when we say that in blockchain, consensus determines the truth?
    Consensus is a mechanism for reaching agreement on whether a transaction shall be added to the blockchain. The blockchain database is decentralized on thousands of computers, and reaches an agreement between all the networked computers. If the entire network agrees that the transaction is valid, that decision is considered “truth.”

  2. How is this different from how truth is determined in a central database?
    In a centralized database, the is usually a single source of data which can be manipulated, changed, modified, deleted, etc. It is an much more vulnerable system than a decentralized one where many can verify the data. Truth is determined by trust. Blockchain is a trustless system.

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#4397

1- In the blockchain, each transaction was verified by consensus and is there for true.
2- A central database doesn’t use consensus to verify the truth.

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#4398

What does it mean when we say that in blockchain, consensus determines the truth?

It means that consesus is achieved by interconnected chain of nodes that verify each step in the process, which removes the need for trust.

How is this different from how truth is determined in a central database?

When we use blockchain there is no need for a central authority to verify the process, hence, there is no need to trust the central organization that they will say the truth. Instead, there is a decentralized body of verifiers who determine the objective truth that can’t be altered.

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