Homework on Consensus - Questions

Blockchain and Bitcoin 101
#81
  1. in a decentralized manner, multiple computers holding onto the same ledger must determine and verify that what is being to the ledger is true. They are incentivized to determine the truth and vice versa for fabricating. This is why 51% attacks are a big deal.
    2 In a centralized database, the central authority determines what is true or not. They essentially write history and control the ledger. Similar to owning over 50% control/equity in a company.
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#82
  1. What does it mean when we say that in blockchain, consensus determine the truth?

It means that everyone (or at least 51% of the network) has to agree that something is the truth before it’s put on the blockchain.

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

In a central database the party that controles the database also controles what’s true and what is not.

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#83

  1. Multiple parties have to agree on the same thing for it to be accepted as truth.

  2. A central database is controlled by a single entity that could manipulate the truth, without anyone knowing.

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#84
  1. What does it mean when we say that in blockchain, consensus determine the truth?
    It means that if the whole nodes that participate in the network don’t agree on the accuracy of an information there won’t be consensus. If there’s no consensus on the information or transaction in question it can’t be added to the block. The other way round if an information or transaction is added to the block we can rest assured it’s verified piece of information.
    2.How is this different from how truth is determined in a central database?
    In a central data base truth is determined by trusting the central entity with out verifying.
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#85
  1. What does it mean when we say that in blockchain, consensus determine the truth? Consensus refers to a network or supply chain which either agrees or disagrees as a whole or consensus concerning a transaction or issue at hand. The blockchain or public ledger is agreed upon or disagreed upon based on the entire network’s decision.
  2. How is this different from how truth is determined in a central database? The difference between consensus in a decentralized database versus a centralized database is that in a centralized database there is one entity that states that something is true or not. Whereas in a decentralized database, the truth is based on a network that agrees or disagrees on a particular matter. With consensus, you remove having to trust one entity because of a decentralize network that provides incentives for each entity to verify data thereby playing by the rules of consensus. In doing so, consensus removes trust but promotes verification.
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#86
  1. It means that due to the decentralized nature of blockchain, we need a way to determine what is true and what is not. We do this by a consensus method which creates either incentives or disincentives to be honest about the validity of the transactions.
  2. In a central database, truth is 100% dependent on trusting the honesty of the governing body of the data, the company. Truth is determined by the people and systems put in place by the company to verify and validate the data. This ofcourse is very prone to manipulation and mistakes.
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#87

Hello everyone, is it possible that the video wasn’t uploaded completely? It seems like it was cut off at the end. All you hear now is “let’s Continue”.

BR Daniel

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#88
  1. A group of peers decides on what is the truth, the majority wins
  2. In a central database only delegats are allowed in the concensus mechanism
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#89
  1. Consensus determines truth because it is not one central authority saying its true and we take their word for it; but a group of many people and computers collectively say its true.
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#90
  1. What does it mean when we say that in blockchain, consensus determine the truth? In order for a transaction to be added to the blockchain, independent parties must agree that it is valid and these parties are incentivized to play by the rules.
  2. How is this different from how truth is determined in a central database? In a centralized database a single party has all the power to define the truth
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#91

1.) Consus is a mechanism where the participants work (in collaboration) for a common goal they want to achieve. As the participant receive incentives, they don’t want to loose reputation, money, etc. You have to play by the rules in order to be a part of that (eco)system.

2.) “Trust” only exists by a single authority. You have no controll, when, what, who is reliable for putting in or alter data. There is no public insight on that processes.

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#92

  1. When information is submitted to the blockchain, it is necessary for the distributed operators of the blockchain to evaluate and agree on the information before it is permanently incorporated into the blockchain.

  2. Traditional centralized databases have been designed to be managed by a limited amount of users without the need for any consensus mechanism across different parties. Thus, the main disadvantage is too much trust.

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#93
  1. What does it mean when we say that in blockchain, consensus determine the truth?

For example, when a new transaction occurs in bitcoin, all nodes in the network must agree that this transaction is valid. Does the person have enough funds in their wallet to spend? If all agree then transaction can be added to the blockchain.

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

In a central database, there are not necessarily any independent nodes validating that the data is correct. There is no consensus, nothing is being double checked. Only one party is deciding on something, not several.

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#94

Wouldn’t the consensus be determined by all participants, not a simple majority?

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#95

1.there is a network of computers that consenses al transactions that are going thru blockchain and they deside if the transaction is valid or not.
2. database is centralised and an authority can intervene

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#96
  1. When a specified number of blockchain operators agree on a block to be added and it is then added to the blockchain which after that all blockchains must agree that chain would be the “truth”. Agreement between a % of miners is the “truth” and therefor that chain has consensus.
  2. A central database on has one truth it’s own. The math and method of the distributed and incentivized blockchain tech is why it’s truth is so much more true that a single source.
#97

Homework on Consensus - Questions

1. What does it mean when we say that in blockchain, consensus determine the truth?
The network participants have to agree on what the next block is. A block which is not built according to the rules will be rejected even if it is the fastest to appear. Because all participants are following the same set of rules to judge whether new blocks are valid or not, blocks declared valid can be assumed to the truth - at least the truth according to the agreed upon rules

2. How is this different from how truth is determined in a central database?
Any information in a central database can be simply the most convenient truth according to the authority in control of it

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#98
    1. What does it mean when we say that in blockchain, consensus determine the truth?
      Blockchain is decentralized and the nodes have a copy of the ledger. With all new transactions consensus between all the nodes is needed for verification. So it is very difficult to cheat. Consensus removes trust and nodes get incentives to do so.
    1. How is this different from how truth is determined in a central database?
      A central data base can be manipulated by one person or entity.
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#99
  1. Consensus in blockchain means a decision is made together by several parties in the system in a trestles way. However, it becomes true through consensus or verification process of a collective group.
  2. Truth in a central database is determined by a central authority.
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#100

1 removes trust because its all open and visible by everyone in the network. result/transactions cannot be falsified and are only given as “valid” when agreed by everyone on the network

2 result/transactions cannot be falsified and are only given as “valid” when agreed by everyone on the network. In a central database the owner of the database will determine when somethings is valid or invalid. can be compromised and falsified too

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