Homework on Consensus - Questions

[Dimitri_N]

1. Because it shows or verifies when a user is cheating or being dishonest.

2. It’s different because there is no incentives on a central database. So, you cannot know if that user is telling the truth or not.

[Cryptek]

1. What does it mean when we say that in blockchain, consensus determine the truth?
   -> It is because several computer, which has the same version of the blockchain, can validate the transaction that is true.

2. How is this different from how truth is determined in a central database?
   -> On a central database, what is written in the database is the truth. You can’t compare it with other version of the database.

[MikeM]

1. Consensus is agreement on the transactions that are accepted into the database. If all the computers in the network agree on the transaction it is accepted as valid. The decisions are made by the group and checked by the group mathematically. Doing this creates a system where trust of one authority is not needed because everyone can check to see that the transaction is valid.
2. In a central database there is one authority that determines the valid transactions. There is no consensus of many computers. One source has to be trusted. There is no way to prove the validity of the transactions.

[Ryan_Lewis]

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

• This means that nodes in blockchain networks are given incentives for accurately reporting the truth. The incentives are financial rewards which explains why mining can potentially be lucrative.

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

• In a centralized environment/database the data is secured and private. Therefore, manipulation can be performed on the data in a centralized database. Which means the truth can be manipulated without verification unless you have access to that database.

[yodasaysso]

1. What does it mean when we say that in blockchain, consensus determines the truth? Since the blockchain is decentralized, it requires many different nodes to verify that transactions in a block before it is accepted to the blockchain.
2. How is this different from how truth is determined in a central database? The blockchain is decentralized which allows for “trustless” transactions.

[epicangel]

1. Through cooperation and incentives computers on the network decide what to allow in the blockchain
   Since good behavior is incentivised through monitary rewards we can say once we have a consensus…we have the truth.
2. In a central database everything is changable and there is no consensus (agreement)

[TonyD]

1.) The nodes on the chain communicate with one another to verify whether the information introduced is true or not. Sense the system is uneditable, there is no way for the information to be manipulated/destroyed

2.) “Truth” requires trust in the other parties involved, with a much more convoluted way of verifying (I.E. Communication with others down the supply chain, if possible, to verify). However, in this system, “truth” can be manipulated/destroyed

[Iceman085x]

Consensus determining truth on a blockchain means all the nodes on the blockchain has a say on whether a certain line of code represents a certain act. The entire population of nodes on blockchain can come to a conclusion and double check other nodes solution. This allows something to be determined as true when the majority of the nodes agree on the same point or piece of data. This differs from a central database because a central database just needs a single entity with authority to decide if something is true. This entity does not need the input of anyone else to determine truth.

[JasonM]

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

In blockchain it is the network of computers that must unanimously agree (consensus) the legitimate transactions that get added to the blockchain.

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

This differs from a central database as here transactions can be removed/updated by a use with relevant access. Essentially the truth is subjective.

[SamuraiDeFi]

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

The blockchain’s de-centralized network of nodes are provided with financial incentives/ rewards to compete with each other, play-by-the-rules & not lie, when verifying which incoming transactions are to be recorded into the public ledger/ database. Transactions are comfirmed, only after the nodes are able to come into a consensus/ agreement, as to their validity/ truth; --Consensus removes trust through incentives.

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

De-centralized database consensus eliminates the need to trust each participant/ stage in a transaction/ supply chain. There is no need of having to rely/ trust on one &/or more centralized persons/ entities being able to confirm a transaction; --Rather, math is used to prove whether or not to trustlessly verify the validity/ quality of transactions/ inputs.

[BHogan]

1. It means that when one puts a transaction or order on the blockchain anyone can verify whether or not that person is being truthful about what they claim to have purchased or claim to own.
   2.It’s different because unlike with centralized databases one cannot fudge numbers or amounts of an item if it is put on the blockchain. Whereas with centralized data it’s in people’s best interest to cheat the system, the risk-reward is high. With consensus people are already incentivized to not cheat the system, making the whole machine run without fraud.

[LuizCyriloA]

1. What does it mean when we say that in blockchain, consensus determine the truth?
   Collaborative work to validate if a transaction is good, and if agreed it is good, then it is added to the chain.
2. How is this different from how truth is determined in a central database?
   Single copy of the DB, so the truth is always the copy you have.

[TravisFoster]

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

We know that several different parties validated the truth as there was not a single decision maker and that all parties in the network reached the same conclusion upon checking the ledger. Everyone is incentivized to tell the truth because it makes them money.

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

In a central database the owner can independently manipulate data because proof of authority is all that is required. This is a system determines it’s “truth” by using trust and generally cannot be audited by parties attempting to validate the proof.

[rahul_mulay]

a) it means all the nodes on the blockchain network needs to come-up with same right answer to reach consensus , the right answer then becomes the truth.

b) In central database, the truth is determined by looking a the one single source with latest transaction which we need to trust is correct, while in blockchain its trust less,

[nmd55]

Consensus determines the truth since in blockchain, a decentralized network of computers must be in agreement to confirm a transaction. It removes trust and is achieving this through incentives. It makes it very hard to cheat.

[pedram_ezzati]

1. because there are plenty of system in blockchain, so each translation should be confirmed with these systems , so it is not possible to put wrong translation in chain because other system will not confirm it
2. in the case of database it can be easily modifed

[ivory_elephant]

1. In blockchain, the addition of new blocks on the chain - which store information on transactions, is done through consensus. Essentially this means that the block is validated by nodes on the network and that a block will only be added to the chain when a large number of nodes agree that the block is true. It is the consensus of the nodes that determines what is written on the blockchain.

2. On a central database, there is no consensus mechanism per se, data is validated by the entity responsible for the input of information. As such the system is designed around the trust of the central entity.

[SmooveSaudi]

1. Consensus is an important decision which lets you know that when a transaction is made on one ledger in the blockchain the rest of the ledgers in the blockchain agree and accept it.

2. Blockchain is a trustless and decentralized network, a decision is made by many parties instead of one governing entity as is the case in a central database.

[CharlieMo]

1. That transactions are valid only when the CPUs in the network agree.

2. Transactions don’t require community verification to be validated. No trustless factor possible

[Daniel.P]

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

With consensus, all transactions can be checked back on to make sure they are legitimate because all parties want to play by the rules with incentives.

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

in a central database the truth can be chosen by the one with authority.