Homework on Consensus - Questions

1 all actors work toward a similar objective so when an individual misbehaves he will be spotted and put aside by the natural consensus generated by all the others

2 in a central database trust is generated by the audit of a 3rd party giving it easily many points of failure

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

The nodes together work to establish if a transaction is true and the it becomes part of the block

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

A central database is not decentralized and can be overruled by a central authority.

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  1. When all the computers agree on a transaction before moving to the next step.
  2. The computers are incentivized to tell the truth.
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1). In a blockchain you need multiple decision makers to determine what the truth is. The parties involved in determining the truth in the blockchain are incentivised to find the actual truth.

  1. In a centralised database the truth can be determined by whoever has control over the database. In this system we are required to trust that the information they hold is the truth.
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  1. What does it mean when we say that in blockchain, consensus determine the truth?
    It means that that the truth is decided by people collectively.

  2. How is this different from how truth is determined in a central database?
    The truth in a central database is determined and decided by centralized authority, not by people collectively. The owner/owners make the truth.

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What does it mean when we say that in blockchain, consensus determines the truth?

The system of compute nodes all verify a claim. Through mulitple independant, non-bias responses a sum of true -vs- false votes will agree on the validity of something. Being that this is computated without human influence the mathmatical detrmination is trusted because the majorty have all determined an output that do not conflict.

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

Truth in a centralized database is established by the admin. In some cases the argument can be made that a baseline of observed results is used as that “truth,” but, due to a limited set of computers in that pool, and a possible corrupt dataset the “truth” is ultimately what the admin says it is.

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Homework on Consensus - Questions

  1. What does it mean when we say that in blockchain, consensus determine the truth?
    Consensus determines the truth due to unity and common ground by the use of incentives.

  2. How is this different from how truth is determined in a central database?
    It can be hidden or erased before the truth reaches consesnsus.

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  1. In blockchain, consensus is built upon incentive, and there is incentive to be truthful. In this way, consensus determines truth.

  2. In a central database, centralised authorities (in whom we need to trust) determine truth. With blockchain, truth is trustless.

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

Consensus determines the truth within blockchain as there is never a central database approving transactions or making decisions on their own. With blockchain, the network of computers (e.g nodes) are consistently validating the transactions based on past records on the blockchain, all together they reach a consensus as to whether the transaction gets confirmed & added to the record or not.
This is usually by validating a sufficient amount of funds in the wallet that is requesting a transaction & the origin of the funds they’re wanting to send.

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

A central database determines truth based on one persons judgement, this judgement can be corrupted, and generally has an individual coming to decision, validating & processing transactions or direction. Therefore, the ‘truth’ can be tampered with, and or mistakes are at a high risk.

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In blockchain mutual agreement by system participants determines whether a transaction is validated, whether an entry is made into the ledger, and whether a new block is written. This is what it means when people say that: ‘consensus determines truth’ in blockchain.

In a central database all transactions are validated by and through the central authority. The central authority makes all the rules - they can say the sky is red - and this determination must be accepted by system participants. Centralised structures are closed systems, there is no way to objectively validate transactions. The consensus mechanism has been effectively turned on its head, because now all participants in the system must accept consensus as determined by the system or the system fails and the party is over.

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Consensus is reached on the blockchain automatically where as a data base needs to be validated by a person or persons

Homework:

  1. What does it mean when we say that in blockchain, consensus determine the truth?
    It means that there has been an acknowledgment among nodes, validators, participants and or other voting means (ex: oracles) within a blockchain to achieve a specific threshold of agreement of what is actually agreed upon as true, valid or otherwise. In this case, a network on a blockchain is incentivized to reach truth some agreed upon vote between those in a blockchain.

  2. How is this different from how truth is determined in a central database?
    In a central database, there may be a centralized power or authority that determines what is true that can override the majority. In the scenario where there is a centralized database and one group, set of individuals or person may have controlling power to veto others and the majority. There may be no incentive to tell the truth as it means to the majority, but only the minority.

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  1. What does it mean when we say that in blockchain, consensus determine the truth?
    Nodes/miners are incentivised to be honest. Dishonesty is being punished.
  2. How is this different from how truth is determined in a central database?
    No incentive is given for any transaction. Central DBs can be easily manipulated.
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  1. All the computers in the blockchain have to agree on what is added to the database (transactions, etc.). Whatever is agreed upon by all the computers is the truth and is added to the database. And the information that is agreed upon to be true and is added to the database can never be changed or altered.

2.) In a central database it can be only one source that determines what is true and not true. One source that determines what is added to the database. Information can be removed or altered by that one source.

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

Answer: as it has been mentioned in earlier videos, blockchain is a network of peer nodes (each node has a full blockchain history). In order for some piece of data to be added to the blockchain (e.g. transaction), the consensus has to be reached between all the nodes - each participant (a node) has to look at this transaction and agree that it is indeed valid and can be added to the blockchain. Once the transaction is verified, participants reach consensus and add this transaction to the blockchain. The decision is decentralized, because everyone is participating in it.

  1. How is this different from how truth is determined in a central database?
    In a central database, there is usually a singly source of authority making decisions. E.g Central bank
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  1. In fact not being able to cheat means that all or at least almost all blockchain nodes are playing by the rules, which means one can be confident that consensus (general agreement) is reached on the decisions to be made, so the result of each decision is trustworthy.
  2. For datasets being valid in a central database it requires trust among the content contributors and operators of the database. A central database is permissioned and usually not open for everyone to verify all of its content and content history.
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  1. No central authority can determine what is the authentic blockchain record. Bitcoin miners are incentivized to get to the truth.

  2. In a central database what will be recorded is decided centrally and can be altered.

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  1. Because the nodes must have consensus before adding a block to the chain, we know that it must be the truth.

  2. In a central DB whoever owns/manages/administers the database get to decide what the trust is.

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1.multiple nodes must come to an agreement before any transactions are added to the ledger, also incentive. People gain money from being honest. 2. in a central data base the owners or worker could be un trust worthy and alter the facts

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Homework on Consensus:

  1. Consensus determines the truth in Blockchain through common agreement of transactions. This is done through agreement among computers within the network on certain transaction elements. The elements include the individual having enough funds to spend, etc. If it is concluded the transaction makes sense, it is then verified and accepted into the database.

  2. The truth within a central database is determined through a single authority or power. Which, lays the way for corruption. However, the decentralized network consensus within Blockchain is a team effort, removing chance of corruption.

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