Homework on Consensus - Questions

Blockchain and Bitcoin 101
#844

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

    In blockchain, to test the validity of transactions we use multiple sources. The transactions that the majority of validators find to be legitimate are perminently written to the ledger. For a dishonest transaction to be validated and written it would require more hashing power than the entire network to overpower it.

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

    In a central database the administrator is the sole arbritror of truth. It is up to them to decide whether each transaction is legitimate or fraudulent. This makes the central database a lot easier to manipulate and corrupt than the decentralised blockchain.

1 Like
#845
  1. What does it mean when we say that in blockchain, consensus determine the truth?

Truth is determined by many nodes on the blockchain network. Those nodes need to agree on the truth and reach consensus, before the truth is published. If a rogue transaction or node is part of the system, all other truthful nodes will be able to identify and reject such a transaction - which would fail consensus.

  1. How is this different from how truth is determined in a central database?
    Truth is determined with a single trust relationship between the central database and the client. A central database is a single point of failure. It could be hacked. Its owner could be dishonest and change the truth. It is mutable.
1 Like
#846
  1. A transaction could only be added to the blockchain if multiple ledgers confirmed it being correct. This is the implied truth — checking each fact (correctness of a transaction) individually, by many parties, guarantees the whole blockchain to consist of the correct transactions.
  2. In central database, only the one who writes to it knows if the data is correct or not. It’s possible to cheat, by writing incorrect data and make it appear correct to all the consumers of that database.
1 Like
#847

  1. Consensus determine the truth means that in blockchain’s network nodes validate new/altered data & information (such as transactions) to be correct. this is done in a decentralised way. Firstly a node will validate a new piece of data on a block such as a transaction and will be incentivised to do so, in the case of a transaction they may be paid a fee to validate the transaction & verify the data on a block. This is then broadcast to the network. By using proof of work (in the case of bitcoin) all the network nodes are able to agree that the information verified by a node is correct. In order for data of a new block to be added 51% of the nodes must accept this. This is the key part of consensus - the network nodes all coming to agreement on the data or information on a block - and this is what determines the truth.

  2. Truth is determined on a centralised database by the entity which controls the database. They have the power to decided what is the truth and what is not. Often companies or entities will need to communicate with eachother to gain the information on what is the truth often with no proof of this being the case. This means the truth of each step of a network such as a supply chain is actually determined by the individual alone with no consensus. Audits and investigations are the only way to determine the truth.

1 Like
#848

  1. What does it mean when we say that in blockchain, consensus determines the truth?
    The transactions can only be added onto the blockchain network if they are verified by multiple public ledgers. These public ledgers verify and fact checks each transaction individually. This ensures to have verified and validated transactions.

  2. How is this different from how truth is determined in a central database?
    In a central database, the owners and administrators are the only ones that may know the true data. They could manipulate information so that it may seem trusted by users but in fact it is not. In addition, a decentralized database may fail due to hacks as well as leaving it vulnerable.

1 Like
#849

  1. In blockchain, you have multiple different nodes trying to verify the same transaction. If one of those nodes tries to cheat and publish false or altered transaction info it will be rejected by the other nodes and they will not receive any block reward. This is how consensus is used to determine truth.

  2. In a central database all transaction info is shared to a single “node” and then that “node” publishes what they determine truth is. This is the danger.

1 Like
#850

1-It means that whatever ALL NODES accept as the truth, it is the truth for the network.

2-In this case the central node decides what the truth is for the network.

1 Like
#851
  1. When we say that in blockchain, consensus determine the truth we mean that it becomes difficult for a company to cheat when there is a whole network of nodes to verify everything that is being done on the chain. Specifically when it comes to marketing and ingredients, etc. For example If a company is saying the source high quality ingredients, and the company exists on the blockchain then you would be able to easily and in real time see exactly where a company is sourcing its material from and if they are lying about something blockchain makes it so it is easily identifiable.
  2. Truth is determined in a central database pretty much by whoever is the central authority of said database. So basically they can just bullshit you and really you would not have much of a leg to stand on in determining wether or not what they are saying is in fact truth.
1 Like
#852

1. What does it mean when we say that in blockchain, consensus determine the truth?
In blockchain, the users all communicate with one another to establish an agreement on the truth.

2. How is this different from how truth is determined in a central database?
In a central database, there is a single point of origin and auditing for data-truth which can be corrupted or manipulated then broadcast to the network.

1 Like
#853

  1. What does it mean when we say that in blockchain, consensus determine the truth?
    Consensus is like voting. If enough people vote for one thing it becomes the truth.

  2. How is this different from how truth is determined in a central database?
    In a central database the Entity holding that database determine what is the truth on its platform.

1 Like
#854

multi party agree on a transaction or event? trust less consensus, everyone can check, no cheating, reward honest,

#855

  1. At a certain level of recorded and added changes there is no feasible way for anyone to gain control of the whole network to erase or change what is recorded. There are different levels for this, and some ways of taking over a network that might be a problem in the future when state actors will attack blockchains.

  2. Any “truth” in a database is relative, depending on the last change done with any account or even low-level tampering with records. Deleting logfiles after changing the data can in many cases make it completely impossible to detect changes.

1 Like
#856
  1. What does it mean when we say that in blockchain, consensus determine the truth?
    • It means that everyone in the network has verified that the propagated transaction is correct. The truth is obtained by verification of the transaction and whether it fits with the consensus rules.
  2. How is this different from how truth is determined in a central database?
    • Compared to a normal database whereby the truth is only verified by the host of the database. Thus, there is an element of trust for users of a central database that the host is not modifying or altering the data in it.
#857

  1. Consensus achieved by network participants, in btc it is done by the record of it’s chain transactions. 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. The ledger then represents the truth achieved by everyone’s concensus

  2. In a central database a single copy database copy or single individual choose what is truth. If the database is corrupted then truth is altered.

#858
  1. The “truth” is defined by the majority of computers in the network. The fact that it should agree with the actual objective state of things (a.k.a. the Truth) follows from the incentives.
  2. In a central database one bad actor could introduce false information, the truth is not determined by the majority.
1 Like
#859
  1. The Bchain sistem is decentralized , so each computer must to verify if a transaction is valid and could be written in the blockchain .So the decision is made insted of one regulatory office by a lot of computers so it gives more trust in the whole sistem
  2. In a centralized databases the true of an information is controled by only one , or few regulators .In Blockchain is a common decision , so is 100% sure
1 Like
#860

Homework on Consensus - Questions

  1. What does it mean when we say that in blockchain, consensus determine the truth?
    It means that when the nodes agree on a new transaction, it becomes the truth and then it forms part of the blockchain
  2. How is this different from how truth is determined in a central database?
    With a centralized control, the facts can be manipulated and unchecked making a lie the truth
1 Like
#861

  1. What does it mean when we say that in blockchain, consensus determine the truth?
    It means that the network needs to agree on what transactions are legitimate .

  2. How is this different from how truth is determined in a central database?
    A database doesn’t need any verification and can be manipulated by a central entity.

1 Like
#862
  • What does it mean when we say that in blockchain, consensus determine the truth?

you only get intensives if you validate in a correct way, so the main goal is to play fair and earn money

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

one central institution is responsible for “telling the truth”… this trust can be manipulated in an easy way… as an example a DB admin is able to change values in the Database and nobody is able to verify this manipulation

1 Like
#863
  1. Nodes in the network communicate and verify that everyone agrees about the blockchain.
  2. In decentralised network all the nodes have a version of the blockchain, and the consensus is reached between them. In a central database there is only one version of the truth.
1 Like