Homework on Consensus - Questions

Blockchain and Bitcoin 101
#281
  1. What does it mean when we say that in blockchain, consensus determine the truth?
  • The nodes in the network need to agree what is true and accept it, or false and discard it. Consensus is built on incentive, ensuring all parties have it in their best interest to play by the rules. This is a decentralised, trustless system.
  1. How is this different from how truth is determined in a central database?
  • There is no consensus mechanism or verification in a central database, leaving it vulnerable to bad actors. Centralised databases are also vulnerable to outages, hacks, data corruption, complete loss of data and censorship.
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#282

  1. That someting is only the truth if more than half of all actors involved agreed to the same truth.

  2. The truth is what one single person believe or claims to believe.

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#283
  1. What does it mean when we say that in blockchain, consensus determine the truth?

Every node has a copy of the blockchain, so every node can indipdentently verify if a transaction makes sense or not. If a node tries to cheat, it’s very easy to spot, as the rest (majority) of the network will give a different result when verifying a new transaction. Thus, the truth is determined by the network, not by a single node.

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

In a central db one must trust that the records in the database are correct. This is very difficult, as it’s easier to hack and modify a central db than modifying all ledgers stored in all nodes part of a blockchain network.

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#284

1.Consensus allows decisions being made by all parties involved. There is no provenance without consensus.
2. It is very difficult to cheat and manipulate with information because everything can be verified due to decentralization.

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#285
  1. Consensus means all computers on the network up to the latest transaction are mathematically validated
  2. on a central database all trust is placed on a person filing in the data
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#286
  1. Consensus determines the truth because it is decentralized. There can not be one or a few bad actors falsifying information because it takes many parties in agreement to verify each new piece of information.
  2. In a central database one party controls the information on the ledger. This is prone to attacks, corruption, error, acts of god, deliberate falsifying. These situations are avoided in blockchain because no one or even a few parties control information, It takes the majority to be in agreement.
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#287
  1. What does it mean when we say that in blockchain, consensus determine the truth?
  • All nodes/computers must come to an agreement to include a transaction or not include a transaction to be put into the blockchain. This provides decentralization because several parties were involved in providing trust instead of a single party. All decisions are being made together.
  1. How is this different from how truth is determined in a central database?

-The truth is verified by a single party and does not provide security and could be dishonest in the information that is shared or stored within a centralized database. Nobody is double checking the information that gives the database trust.

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#288
  1. Meaning there is no need to “trust” a 3rd party to determine data accuracy. Since the database or ledger is unchangable, and decentralized mathamatical verifications of potential descrepencies will be detected.
    2.When a database is centralized, there is no way to determine if that party is telling you the truth as it is purely under their control. Consequently, you have to “trust” them whether or not they are honest.
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#289

What does it mean when we say that in blockchain, consensus determine the truth?
Blockchain determines truth as consensus has real time agreement of validation. Its like all the partners in a business come to the same conclusion on a matter. Things are validated.

How is this different from how truth is determined in a central database?
Consensus is different from a centralized database because consensus is validation by all the partners on the blockchain. A centralized database is extremely unreliable and has one validator which is a weak spot in the validation. In essence the consensus makes validation much easier and less work.

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#290

  1. Consensus is dependant upon every user of the network, in that they all agree on a certain thing to be true. Transactions and other details visible on the public ledger are easily agreed upon and added to the blockchain, or they are discarded.

  2. If the database is centralized, then the network is vulnerable to manipulation, censorship, incorrect auditing, etc. One main authority in a centralized network could potentially declare what they want the truth to be, and then silence or otherwise censor other users in the network who are not in consensus.

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#291
  1. What does it mean when we say that in blockchain, consensus determine the truth?

CONSENSUS removes trust. All results/outcomes are achieved through consensus.

Everyone is incentivised to play by the rules. Everyone is incentivised to tell the truth. Participants are financially rewarded to play by the rules and “tell the truth”. All nodes need to agree what is true/not true. Include transaction in blockchain? Or not?

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

When a decision is made on a blockchain, several parties (the nodes) are involved to reach a consensus. Before a transaction is written into the blockchain, all parties must verify and agree it is correct.

On a standard database, the process of writing “facts” int the ledger is not decentralised or trustless, and does not require consensus to record “the truth”. It can involve one individual, who can also delete/modify the data.

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#292

  1. What does it mean when we say that in blockchain, consensus determine the truth?
    It means that mutliple parties have decided that a transactionis is valid and can be added to the blochchain.

  2. How is this different from how truth is determined in a central database?
    This is different from a central database where a single authority decides when a transaction is added to a database.

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#293

1. What does it mean when we say that in blockchain, consensus determine the truth?
Consensus is the set of rules that determine the validity of new transactions. When we say that consensus determine the truth, we mean that we let those rules determine the validity of transactions and the state of the ledger.

2. How is this different from how truth is determined in a central database?
In a central database, there is no set of rules or system to determine the consensus. In most cases, a single person or board of people can determine the truth.

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#294

1- The network only accept the true and validated transactions and invalidated transaction is not accepted

2- In central database, date are recorded based on trust with the editor while on block-chain it based on consensus

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#295

What does it mean when we say that in blockchain, consensus determine the truth?
Consensus is agreement among server nodes in a blockchain network regarding the overall state and the validity of new blocks within that context. New blocks by definition, must substantiate the existing blockchain, so nodes collectively confirm truth about overall state when accepting new blocks.

How is this different from how truth is determined in a central database?
Central database truth is simply a report of current state without trustless protocol-level verification.
It differs from the blockchain truth consensus mechanism in two ways.

  1. Central database truth is not established within the context of history or a verifiable audit trail.
    There is no temporal constraint mechanism within a central database against which to test integrity.
  2. Central database truth is not maintained and confirmed autonomously by a network of server nodes.
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#296

Question 1

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

In blockchain consensus is determined not because someone says its true.If all the ledgers running on the nodes in the network verify a thing to be true then there is consensus.

Question 2

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

On a central database records can be altered either maliciously or through hacking to alter a record and there is no way to verify a record has not been altered and by whom. A central database has no external trusted copies to verify in real time a record is true or not.

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#297

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

Consensus is created throgh nodes in a network checking and verifying each others
copies of the database. When a big enough group of nodes in the network agrees on
the same database-copy, you reach consensus, which is the truth in blockchain.

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

In a central database you have a central actor that decides what is true or not.
This makes it more likely to be manipulated, and also an easier target to attack with
a single point of failure.

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#298

1 all nodes in the block chain are intensified to tell the truth. In a decentralized network it is hard for a single member to tell not the truth, because all information is verified by the network and once there is
wrong information, this information will not be verified and with that not taken in the consens of the network
2 in a central db you have the single point of truth and have to trust the central organization

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#299
  1. It means that the collective agrees and determines the truth.
  2. In a central database there is an Authority that decides how the truth is determined.
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#300

Homework answers.

  1. All parties need to agree whether transaction true or false. I see consensus as a agreement, if all nodes determine truth then it can be written on blockchain.
    2.Central database can be manipulated by the owner of database, central db owner can refer to third partie but who ever is doing research is going to lose time and money on doing research. But on blockchain consensus all parties have to agree on the originators claim/transaction etc.
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