Homework on Consensus - Questions

Blockchain and Bitcoin 101
#2311
  1. It means that the network has to be in agreement that a transaction occurred. Without consensus, the truth cannot be known.
  2. In a centralized database, there in no consensus. Blockchain contains multiple computers which need to agree in order to verify.
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#2312

1.) the individuals involved come to a trustless based agreement thru the use of blockchain.

2.) centralized databases are not trust less systems by design.

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#2313

If the math doesn’t work it’s not true. Can’t be forged
Central database is full of fraud because it’s trusted by whom? Completely untrustworthy.

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#2314

  1. What does it mean when we say that in blockchain, consensus determine the truth?
    Consensus in the blockchain is determined my multiple random people verifying the data.

  2. How is this different from how truth is determined in a central database?
    The truth in a decentralised network is incentivised by financial rewards making it trust-less and verifiable. Truth is determined in a central database by needing to trust the people running it.

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#2315 
1. What does it mean when we say that in blockchain, consensus determine the truth?

The truth is only accepted to be the truth when everybody agrees (consensus) that something is the truth.
2. How is this different from how truth is determined in a central database?
In a central database there is no others required to give consensus before a change is made to the database.

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#2316

1- It means that false transactions will be rejected, and only those approved by “consensus” of all nodes will be added to the blockchain
2- Truth in a central database is not decentralized, and is not determined by consenus. Instead we rely on a 3rd party to validate and confirm truth. To do so, we must place trust in that 3rd party

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#2317
  1. It means all different ledgers can verify transactions, their provenance and see whether or not they are real. Blockain throughout its network validates only real transactions.
  2. A central database could not reach consensus since it’s operating by itslef therefore biased.
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#2318
  • What does it mean when we say that in blockchain, consensus determine the truth?
    Every transaction is being checked by all nodes in the network database independently and only when when they have a consensus meaning they all come to the same result, the transaction is being approved.
  • How is this different from how truth is determined in a central database?
    There can not be an independent verification by countless parties, because only one party - the central database - is involved.
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#2319
  1. What does it mean when we say that in block chain, consensus determine the truth?
  • People in block chain have to come to a general agreement to what is true or not
  1. How is this different from how truth is determined in a central database?
    ~ That the people mining transactions have to come to a general agreement together for what is true where in central there is a hierarchy for who is deciding the truth
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#2320

Consensus determines the truth is the process of the nodes verifying the Blockchain is correct. For the Blockchain to be correct all the nodes must agree.

You didn’t really cover the workings of other central databases however I’ll say Blockchain is different because information can not be taken away or manipulated and all the nodes must agree in order for a transaction to be completed
Also centralized databases aren’t public

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#2321
  1. If one aspect of the transaction input has a computer of the network (blockchain) in disagreement, there can be no consensus. The whole computer network must be in agreement.
  2. A central database does not have any network of checks and balances.
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#2322

  1. it means that all information stored on blockchain has to be first confirmed/validated by all parties.

  2. Blockchain users are incentivized for being honest. blockchain is decentralized means there is no “higher authority” to interfere in the process.

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#2323

Because the database/blockchain is decentralized and transparent which makes it trust less. All nodes are independent in verification process.
In central database the database can be manipulated as required without any verification. There is no transparency. We have to trust what is been told or shown.

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#2324

  1. It means that the information agreed upon by the participants of the blockchain becomes the right information, is unchangeable and will be used for future references. If some of the data does not fit the consensus reached by the network it will be rejected.

  2. In a central database there is only one party responsible for approving data, which can be altered or removed by it afterwards. Blockchain removes the need to trust the governing entity’s honesty by agreeing upon the data as a network of nodes, that earn by being honest and preventing cheating.

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#2325
  • What does it mean when we say that in blockchain, consensus determine the truth?
    [Andy] Consensus mechanisms help blockchain networks verify which transaction is true and which is not.
  • How is this different from how truth is determined in a central database?
    [Andy] The difference lies at the number parties involved in the verification process. Blockchain requires a wide range of validators whereas central database only needs one.
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#2326

1- Consensus determines truth in the sense that all actors can check and agree on the record of transactions and each new block has been validated by the network

2- in a central database the owner of the database will unilaterally decide how to alter the database so the truth is determined by a central authority

2 Likes
#2327

When a system is decentralized, the community of miners must all agree on the transaction for it to be entered onto the blockchain. In a centralized setting, a very small group has the authority to manage its ledger in any manner they see fit.

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#2328

  1. What does it mean when we say that in blockchain, consensus determine the truth?
    In case of Bitcoin it is the verification of a transaction by decentralized nodes were each node has the incentive to tell the truth.

  2. How is this different from how truth is determined in a central database?
    It can be altered by the central database owner and there is no incentive to ban fault play.

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#2329
  1. Consensus determines the truth because every transaction requires the mutual agreement of many nodes. You can not cheat the system because you are incentivized to be honest.
  2. Truth is not really determined in a central database because it is based on trust.
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#2330

The consensus has at least more than 50% and this must be the truth than, every node has a copy of the blockchain, if somebody tries to doublespend or anything like that the network will not agree on it so the transaction will not get accepted, there is no real truth in central database because in a central database false entries do not even get found or just overseen. With Swift to make a money transfer from europa to the usa it could happen that the money disapears and this used to happen 5 to 8 times every year.
Nobody needs banks!

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