Homework on Consensus - Questions

Blockchain and Bitcoin 101
#5792

  1. It means that not only one central entity can determine the truth but that several entities need to reach consensus which then determine the truth.

  2. A single database doesn’t have another entity for verification which means that it can determine “truth” by itself/easier but it’s subject to that one database.

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#5793

  1. The network of computers have there ledger, so every transaction gets double checked and need anetwork validation. It´s in the interrest of the comunity to be honest, which makes it impossible to cheat.

  2. Since there is only one owner of the database you need to trust. The owner infact can delete, remove, add or simpliy manipulate the Database in there own favour.

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#5794

  1. What does it mean when we say that in blockchain, consensus determine the truth?
    every transaction or certain value can be validated by checking the ledger of every node in the network, and if most nodes holds the same information, it becomes the truth.

  2. How is this different from how truth is determined in a central database? In central database, the truth is determined usually by single main database, hence alot less reliable than information (database) that being held and approved by multiple sourcse

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#5795

1. What does it mean when we say that in blockchain, consensus determine the truth?
In blockchain, every node in “the supply chain network” speaks to each other and is incentivized to “tell the truth”, any nodes that don’t tell the truth will have a negative effect. Due to this, all nodes tell the same thing, which is consensus; this consensus creates a decentralized and trustless network as everything gets verified in the same way.

2. How is this different from how truth is determined in a central database?
Usually a database only exists on a single server (with potential backups and read-replicas) and has full CRUD permissions on it (for at least some users); this would be the “central” database. The way “trust” would be determined in a central database would be reading the records and whatever get’s read at the time of reading would be “the truth”, even if those records were updated/deleted. Yes, it’s possible to record all changes to a database, but even those can be altered if you have the right permissions to do so.

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#5796
  1. What does it mean when we say that in blockchain, consensus determines the truth?
    Because all the nodes decide if the transaction or decision is to be put in the database.
  2. How is this different from how truth is determined in a central database?
    Because nodes gain financial incentive by verifying truth and being honest.
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#5797

  1. It means that the truth is verified by a network rather then separate parties. Every part has to confirm and verify a single exchange.

  2. A central database will not be available for everyone, hence the truth can only be determined through individuals or groups that have access, which again removes us from the faculty of not having to trust.

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Homework on Consensus
#5798

  • What does it mean when we say that in blockchain, consensus determine the truth?
    JL: Consensus means that all or majority of parties or nodes within the blockchain network must agree on the transaction for it to be posted onto the blockchain.

  • How is this different from how truth is determined in a central database?
    JL: In a central database, the truth is determined by a signle/small no. of actors. The rulesets to determine the truth can be amended without communication/agreement with the community/network.

[/quote]

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#5799

What does it mean when we say that in blockchain consensus determines the truth.
The nodes on the network independently verify that the transaction is genuine (prior to the transaction being added to the blockchain). This is consensus. The resulting truth is based on verification, no subjective trust necessary.
How is this different from how the truth is determined in a central database?
Truth in a central database is defined by the central entity. Everyone else must subjectively trust them.

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#5800
  1. Consensus is the agreement of the net work on state changes based on most recent 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.
  2. In a central database a single copy database copy or single individual chose what is truth. If the database is corrupted then truth is altered.
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#5801

1.) we had a network consensus, that means every node/miner in the chain talks to eachother and if this happend everbody validate the transaction and that makes impossible to cheat somebody. The chains give also the miners who validate an incentive to stay correct.

2.) For example: we had a supply chain with five suppliers, nobody knows something from each other and every one can cheat to eachother, what means that you might have trust to the supply chain. Thats completely the opposite to decentralization and a trustless network.

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#5802
  1. Consensus means that the participants in the network agree on the state of the blockchain.
  2. The state of a central database is determined by a single entity, not a p2p network.
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#5803
  1. Consensus determines the truth because when a new transaction is going to be added to the blockchain, it is only accepted if it is the truth. The nodes must all come to agreement, following such the transaction is approved to be added to the blockchain. A transaction will not be added to the blockchain if it is not agreed upon via consensus.
  2. Truth in a central database does not rely on consensus. One person could say this, the other person could say that. It relies on trust, and not on the blockchain.
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#5804
  1. What does it mean when we say that in blockchain, consensus determine the truth?
    Consensus is the collective agreement from the nodes of the blockchain network, that a new information is valid and therefore can be added/stored in the ledger —> “we reach consensus”
  2. How is this different from how truth is determined in a central database?
    Consensus “removing trust”: Blockchain is trustless because all decisions are made decentralized by different parties (they are double checking the “truth” instead of a central authority)
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#5805

  1. What does it mean when we say that in blockchain, consensus determines the truth?
    Consensus is accomplished by providing financial INCENTIVES, paving the way for the computers on the Blockchain network to play by the rules and, more importantly, telling the truth (validating transactions).
    ALL computers in the Blockchain network agree what is true and what is not. So, all decisions are double-checked and made together, making it very hard for anyone to cheat. After agreeing, the information is stored permanently in the database/ledger.

  2. How is this different from how truth is determined in a central database?
    Instead of multiple parties on a network double-checking the information that will be written permanently in a decentralized database, only 1 central authority is in charge of the central database of information (e.g., a Bank). There is no transparency of information and may be subject to manipulating the data (depends on incentives).

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#5806

  1. Because Blockchain is a network of various nodes, all nodes need to agree on a transaction before it can be determined to be a legitimate transaction. This is how consensus is reached in blockchain.

  2. In a central DB, only one authority determines what is the truth, e.g, a central bank determines whether a transaction is legitimate or not, and we just accept the “truth” from the central bank.

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#5807

1. What does it mean when we say that in blockchain, consensus determine the truth?
In a blockchain, every party involved in the blockchain needs to agree/verify on any addition to the chain, hence “truth” is established by everyone.

2. How is this different from how truth is determined in a central database?
In a central database, “truth” is determined by a single active entity, and whatever the entity says/provides/serves is accepted as true by default by the database clients

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#5808

  1. the truth is determined by all the nodes coming to a consensus where there cant be another version of the truth to be be in a block

  2. a central database truth can always be changed depending on who owns it or who is given authority to change the data.

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#5809

  1. Determining the truth through consensus on the blockchain is done when all nodes come to agreement on any particular transaction/set of transactions

  2. With centralised databased, truth can be determined and manipulated by whoever has control of the database

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#5810

  1. Nodes verifying the truth. We reach consensus through incentives.

  2. In a central database, the central authority decides the truth while in a decentralized network the nodes decide what the truth is by verification.

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#5811

1.This means that network validation prevent fraud. Multiple nodes are required to make a decision. They are incentivized to discover the truth. Network redundancy prevents accidental loss.
2. This is different as in the central database the owner can corrupt the database himself. Proof of authority is all what is required. It is difficult or impossible to independently audit.

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