Homework on Consensus - Questions

Blockchain and Bitcoin 101
#1771
  1. All transactions are validated by multiple nodes on the decentralized network which must agree. If true, the transaction is accepted and added to the blockchain. If found false, the transaction is not added to the blockchain and is rejected.
  2. A centralized database has no continual independent oversight of data integrity. There is only one authority here, and that authority can choose how to manage or mis-manage their data.
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#1772

the truth is scrutinized by many different people and computers (nodes) worldwide with little or no interaction between each other hopefully creating an environment of neutrality this reduces a bias that could colour the result they then add to the ledger or discard the information
2 a centralized database can be manipulated by individuals or groups it can be edited and have its focus changed the people who work with a company i.e. investors have to rely on the honesty or competence of the database and the people who work with it with a database that is diverse and rechecked by peer checked it is not as likely that greed or manipulation would take hold and maintain its hold added to the fact it can be publicly checked at a seconds notice by anyone on the system that adds a deeper level of security …it brings the bad deeds only grow in the darkness

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#1773

My answers:

  1. The network of computers work together to verify if the transaction makes since, which would then be approved
  2. Because in a central database, it’s only using one source which is not checked against others to hold each other honest.
#1774

Hi there! Yes, so everyone verifies and approves changes to the blockchain, so this agreement determines truth.

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#1775

1.- It means that the computers that verifies the data that wants to be integrated in the Blockchain needs to agree on the fact that this data is true or not. These computers are financially incentivized to tell the truth.

2.- In a centralized database it’s easier to influence and therefore manipulate the consensus decisions. Whereas, in a decentralized database network ( Blockchain ) it’s harder to coordinate such an influence.

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#1776

  1. It means that you can’t lie while you are a part of the consensus, because all data are automathicly verified by the network.

  2. In central database there is an authority, which we have to believe in.

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#1777

Answer:

  1. In blockchain, consensus are achieve by various computers agreeing to a transaction authenticity which these computers are incentivised to tell the truth.

  2. In a central database, it is very difficult to trace the network source of the supply chain resulting in unverifiable sources providing bad supplies.

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#1778

Homework on Consensus - Questions

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

All changes in the database (blockchain) has to be agreed upon by all the nodes. The nodes check certain rules, and if they’re all in agreement that the rules have been met, they reach consensus. This makes it trustless. One can trust the data that the network has agreed upon as the truth.

As an example, a food supply network could also commonly agree on certain rules about food related information.

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

Truth (data) in a centralized database can only be changed by entities that have been given permission to change it. Therefore one can not trust a centralized database to be true without also trusting the same entities.

In a blockchain network, instead, one only have to trust consensus (the rules of the network). Every network also has an insentive to follow the rules.

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#1779

A given number of computers must agree on what is true and what is not true. If that given threshold is met (6 confirmations in the case of Bitcoin, for example) then the transaction is said to be true because it has reached consensus.

Actually, truth can’t be determined with a central database at all. “Truth” in a central database is just an a priori assertion by an authority. You must trust the central database completely and have no way to validate it. The opposite is true with blockchain - truth is verified by a number of nodes instead of decreed by one authority.

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#1780
  1. Each computer has a complete “ledger” of all transactions. All the computers in the network have to agree that is true. If it is not true (specifics of the transaction) it will not be processed.
  2. There is no consensus mechanism in a central database. Data is just stored as is.
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#1781

  1. If the network agrees a transaction is good it gets added to the ledger and if the network finds it to be false it gets discarded.

  2. Since if the central database gets corrupted the truth is altered.

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#1782
  1. A majority of the nodes agrees that a transaction is valid, and then it is added to the ledger.
    2.In a central database a single entity can decide the validity of an input.
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#1783
  1. All nodes in the blockchain are incentivised to “tell the truth”. Each node verify each new transaction.
  2. In a central database truth is based on trust. In a decentralised database truth is based on consensus through verification.
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#1784

  1. consensus is the decision of accept and confirm each transaction and be double checked by the network. the truth is verified so cannot cheating.

  2. in a central database is difficult to verify every transaction, or source of information. fake information can’t be avoided. the truth in a central datyabase can easily be manipulated.
    in consensus it builds on incentive. truth behavior makes reward wich is not the same case in a central database.

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#1785

Again, I like to start with the simple definitions, so, consensus means a general agreement. In blockchain this consensus, this general agreement is achieved by the decentralized network comparing the actionable data being requested to enter onto the public ledger, or blockchain. When all in the network agree that the actionable request is valid, it is allowed to be recorded. Remember, once recorded it can NOT be removed. This creates trustlessness, or verifiable actions open to real time audits, which is then truth. In other words, just because I say I did something doesn’t necessarily mean I really did it; even if five of my friends agree that I did it, it still might not be so. However, if I have the entire teaching staff of the university stating that, yes, I completed all the classes required for my degree, then that consensus makes it true.

But let’s take that one step further, I have a document that states that I have a degree, but is it verifiable, or did I obtain it like that character in the movie Catch Me If You Can? Did I just make a very convincing forgery? This now illustrated how truth is determined in a centralized database. In this example, the university is the one single party that has decided that I have completed the required classes for my degree, and the other universities and businesses looking to hire me, “Trust” that the university I attended did, in fact teach all required subjects for the position I am applying AND that I completed all classes. My prospective employer is “Trusting” both that I completed all required classes AND that the classes pertained to the position for which I am applying.

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#1786

  1. Consensus determines truth by using verification through provenance and the decentralized network.

  2. The truth of a centralized database is prone to manipulation based on who has access to the data.

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#1787

Provenance is the ability to track something to its origin. Bitcoin POW (Proof of Work) consensus gives us provenance. Consensus determines the truth because all miners are double checking each others proof of work. Everyone must follow the rules of the network if they want to be rewarded for their contribution :smiley:

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#1788

Okay. are you trying to tell me that my answer is wrong? Consensus comes from provenance, consensus is the agreement among a group of entities that something is true. Provenance is the chronology of data that the entities must reach an agreement or consensus.

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#1789

It was half right half wrong. Provenance comes from the consensus. You switched it. In the original answer you should remove provenance.

“Consensus determines the truth when all nodes in the network come to an agreement in a decentralized way.”

This means that the truth is being verified by many computers, giving as feature such as provenance. Without consensus we wouldn’t have provenance. I hope this made it more clear now. :slight_smile:

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#1790

Consensus come from incentive