Questions tagged [validation]

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40 views

What would happen if I publish a modified version of an earlier block? Would it be rejected immediately by peer nodes?

I am reading the book "Mastering Bitcoin" and have finished reading Chapter 2 and 10, but I still don't find the answer. Suppose the current main chain has 5 blocks: B0 <- B1 <- B2 <- B3 &...
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2answers
124 views

How nodes verify if the hash on a P2SH output is from a valid script?

I understand how the validation works if someone wants to spend coins from a multisig address. But what if the receiver makes a mistake and provides an invalid script hash to the sender? Is there ...
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2answers
83 views

Does a node validates a transaction that comes with a block if it's already in its mempool?

Except for checking for double spends, if there's a transaction in a block that's already in the node's mempool, it can theoretically skip its validation. Does it actually happen, or the nodes ...
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1answer
526 views

Script to periodically update assumevalid block in bitcoin core configuration, good idea?

On my server my full node Bitcoin Core 0.15.1 can take several minutes, on starting, to "validate blocks". And during that time it's thrashing the disk, slowing down everything else. So I discovered ...
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1answer
546 views

Selfish Mining: stale or orphan?

In terms of a selfish attack many sources speak of orphaned blocks, i.e. blocks that are not on the main chain and thus not paying any coinbase transaction to its miner. Still I'm not sure and ...
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1answer
27 views

What do the classes ChainstateManager, CChainState, CChain and BlockManager do in Bitcoin Core?

What do the classes ChainstateManager, CChainState, CChain and BlockManager do in Bitcoin Core? Why do CChainState and CChain have a leading 'C', but ChainstateManager and BlockManager don't? These ...
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1answer
32 views

What does validation cover conceptually in the Bitcoin Core codebase?

What does validation (.h and .cpp) cover conceptually in the Bitcoin Core codebase? This question was asked by Larry Ruane at the May 12th 2021 Bitcoin Core PR review club on a Carl Dong PR to de-...
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1answer
55 views

How does the network verify previous transactions when transferring BTC between two users?

When transferring BTC between two users, the new transaction will consist of references to previous transactions. For example, if I user A wishes to transfer 1 BTC to user B, he will need 'n' ...
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1answer
66 views

How exactly does the network know if the miner has put forth a valid proof of work?

If all that the miner needs to do is find a hash with a certain number of leading 0's of the block's header, couldn't they just find a random hash with the required number of 0's that isn't ...
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1answer
73 views

Regarding block validation in blockchain

In mining process, miners validate the block based on proof of work or using some other consensus mechanism. Miners also validate the block. So in this validation process, miners validate only hash ...
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1answer
53 views

Is there a way to determine the difference between a BTC prefix 3 address and a LTC prefix 3 address?

I am trying to determine if there is a way to tell the difference between a BTC prefix 3 address and a LTC prefix 3 address, for validation purpose. Example if given this public key address: ...
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1answer
97 views

How 1 cpu 1 vote works?

How 1 cpu 1 vote works? What is its validity? Does it use IP address or mac address or similar to that? If yes, then it can be changed and can make fool to the network. If it can't, then how is it ...
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1answer
105 views

How miner makes sure that a transaction he picked up from mempool is actually valid? [duplicate]

I have read and searched enough about the roles and responsibilities of miners here; For example: Does the miner first validate transaction before doing POW or he does not validate at all ? Does a ...
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1answer
94 views

Verification of untypical scriptSig

I want to be able to redeem a P2SH output with a script doing a multisig but also additional checks. The scriptSig to redeem this output thus has to provide enough signatures, as well as some specific ...
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1answer
87 views

Where in the source code are transaction validation checks implemented?

I understand that consensus (mining) and transaction validation are different concepts. Correct me if I'm wrong, but I believe each full node validates transactions and puts the valid ones into its ...
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1answer
196 views

Is it possible to append new blocks to a block of arbitrary age?

First of all, I'm aware of 51% attacks and how they work. Though, I was wondering, if Bitcoin and other blockchains allow appending cryptographically valid, new blocks to blocks of arbitrary age (if ...
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1answer
743 views

How can one verify the address you are sending BTC to

I've had an incident with an exchange that provides addresses to deposit BTC funds. For some unknown reason, the exchange is telling me they have never received the funds. I read the address with a QR ...
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2answers
726 views

Blockchain and Transaction Validation

How do the miners check that I have enough Bitcoins. I cannot believe that they will walk through the huge and always growing blockchain established from 2009 to check each Transaction I made to ...
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2answers
347 views

Easy way to accept bitcoin payments without external service

Is there a way to accept Bitcoin payments without running a full node or rely on an external service? I'm thinking in some way to validate the transaction and then broadcast it to the network.
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1answer
30 views

Block Validation Process, in Terms of adding Block to the Chain

quick question - How does a Node react to a new block propagated to the network? In Terms to does a Miner stop mining when "he" gets information of a new block to validate it? or does it ...
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2answers
144 views

When are blocks validated?

Are blocks validated just before they are stored to memory, upon receipt from an RPC submit call, or at some other time? Can you point to the place in code where this validation process begins? Is ...
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0answers
127 views

Validate chain from `valid-headers` to `valid-fork`

The getchaintips JSON-RPC returns multiple branches of the blockchain. Chain tips can be in various statuses. The active and valid-fork are already validated chains. There is a valid-header valid-...
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3answers
103 views

Reject or refuse to relay a valid transaction

Under the Bitcoin protocol, how much control does a node have on how a transaction is dealt with once received? Can a node reject a valid transaction? Can a node refuse to relay a valid transaction to ...
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1answer
98 views

Does bitcoin validate transactions against the mempool?

I want to know whether or not bitcoin checks for the existence of transactions in the mempool as one of the many validation rules it performs for new blocks. If a transaction most exist in the ...
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3answers
109 views

Why must the entire chain be included in calculations if it's already been validated. Why can't the validated portions be archived to save energy? [duplicate]

I'm new to this so don't laugh. If all of the previous transactions in a blockchain have been validated as authentic, why does the entire chain have to be carried forward in the calculations? Why ...
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2answers
392 views

validation of a block with false transactions

When a miner can find a number to create a hash with enough zeros, the other miners can verify his work by testing that number and seeing if everything is correct. But how do they verify that the ...
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1answer
69 views

How do nodes come to consensus on whether a timestamp is valid?

From bitcoin wiki: A timestamp is accepted as valid if it is greater than the median timestamp of previous 11 blocks, and less than the network-adjusted time + 2 hours. If a miner submits a block ...
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1answer
42 views

Who set the rules for validating a block in blockchain?

Who set the rules for validating a block in blockchain? The rules can be set the creator of the blockchain network. There might be some rules on the application that uses the blockchain network. Is ...
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1answer
58 views

Can op codes be used instead of signatures?

Are there any op codes or combination of opcodes that can be used instead of a digital signature when creating a transaction?
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1answer
99 views

How can you send a transaction directly to the memory pool?

Is it possible to send a transaction to the bitcoin memory pool directly to have it mined without validating it?
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1answer
49 views

How do nodes contribute to security when the power comes from mining and what is the chain of transaction validation?

Blockchain security comes from the decentralisation of hashing power by miners. They append transactions to a block, perform PoW and add them to the blockchain when that validate blocks. How do nodes ...
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2answers
77 views

library for validating bitcoin private and public keys

I am building a python script that gets a string and determines if it is a valid bitcoin private key or public key, and if so it returns its type/format (base58, BIP32, HexaDecimal etc.) and its ...
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1answer
57 views

When a new block is propagated, nodes validate from genesis block to propagated block?

For example, I have a nth block and when n + 1 th block is propagated, i have to compare with n+1 block's previous hash and nth block's hash for validation. It is pretty trivial. But do i have to ...
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1answer
305 views

How does the p2p network monitor the validity of a transaction?

In Bitcoin, in order for a transaction to be added to the pool of valid transactions that will be added to the chain block by the miners, at least 51% of the nodes/peers need to review that ...
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192 views

Verifying ownership of utxos [closed]

Is there any other way besides signing a transaction to verify ownership of utxos?
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1answer
57 views

Why does bitcoin use signatures to verify transactions?

Why does bitcoin use signatures to verify transactions in order for them to be broadcasted and mined and is there any other method that could be used instead of signatures?
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1answer
845 views

How to create a valid unsigned transaction

How can I create a valid unsigned transaction which can be broadcasted and mined using these addresses? Could someone create the raw transaction and show me? sender's address: ...
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1answer
63 views

Must block contents be stored with the proof that they haven't been changed?

The replication of the block contents across all full nodes has been bothering me for some time. Isn't the header of a block enough for me to validate the block contents if and when I get them (which ...
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1answer
237 views

Wallet validation methods (centralized, SPV, etc.) - please clarify for Ledger and in general

1) ledger: https://bitcoin.org/en/wallets/hardware/ledgernanos/ Variable validation - Payment validation features are provided by the software wallet you use with this device. 2) wasabi: https://...
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1answer
106 views

Bitcoin RPC RegTest not validating addresses

I am attempting to use Bitcoin RPC in regtest mode, however, when I try to validate a bitcoin address with the following function public function validateAddress($address) { $command = new \...
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1answer
41 views

How and why we need to validate a transaction?

I've starting doing some researches about the Bitcoin protocol and the blockchain. I'm trying to understand all the sections in the Bitcoin white-paper. So far, i couldn't understand what is the ...
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1answer
100 views

Private Blockchains: Validation

I'm a software developer, and I have some questions about private blockchains, I'd like to have technical answers since I'm trying to understand blockchain at a code level. I'm going to write a ...
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2answers
448 views

Ttransaction validation in the bitcoin blockchain

I am confused. What is exactly a validation of transaction in the bitcoin block chain? Please correct me if I am wrong. I know we need 6 minner to validate our transaction and those 6 minner check ...
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1answer
126 views

Tendermint consensus: Are validators “known” and “pre-selected”?

What are similarities and differences between Tendermint consensus and Proof-of-Stak? For example, in both consensus, a validator is selected randomly (I think in Tendermint consensus they are ...
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1answer
83 views

Consensus roles for op_return

What is the validation rule, not policy, for op_return? What is the maximum length of the data that can be attached? Is it 514 bytes? As if the maximum script size was 520 bytes -1 byte for the ...
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1answer
45 views

verifying my modifications to bitcoind w/o broadcasting anything

I want to verify that my updates to the bitcoind source code don't break anything. One way that I thought of doing that was through loading the mainnet data into a regtest instance. To do that I first ...
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1answer
179 views

Can you create a valid p2sh transaction with the redeem script in the scriptsig alone?

From my understanding, for a p2sh transaction to be valid the redeem script must hash to the same value as the output script being used to fund the transaction. So can't you just put the redeem ...
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2answers
29 views

Create a transaction which sends bitcoin to the address it's being sent from?

Let's say address X has 1 btc. Can you create a transaction which would send the 1 btc from X back to X and broadcast it without having to sign it, since the 1 btc is going back into the address it is ...
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1k views
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Is every bitcoin transaction (eventualy) validated by every miner? [duplicate]

I can see that my bitcoin transfers becomes real when my exchange detects 2 or more confirmations. I believe each confirmation is a validation. Am I correct? If so, How many confirmations will have ...