Questions tagged [validation]

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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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39 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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TX Validation: Can a miner choose specific tx to validate from mempool? [duplicate]

I have made two TXs few days back and they remain unconfirmed so far. Can I be a bitcoin miner and validate them myself? And what happens if it remains as it is? There are some big amount of utxo ...
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2answers
227 views

How are transactions verified with only the Bitcoin address, not the public key?

I understand how asymmetric cryptosystems and digital signatures work: You generate a (private key, public key) pair. You never share the private key, you make the public key ... well, public. You ...
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45 views

What will happen on creating a transaction with negative amount?

Bitcoin in short is a public ledger guided by consensus of its nodes. In theory, if there is no validation of transaction amount, if we were to create a transaction with negative amount, that would ...
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283 views

Is it theoretically possible to have an inverted nLockTime?

For example, an nLockTime == 500 prevents a transaction from being included in any blocks before the block 500. Why isn't there a parameter like nExpireTime == 500 that prevented a transaction from ...
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68 views

Does Bitcoin Core validate signatures by default?

There have been claims recently of Bitcoin Core not validating the signatures in a block by default. If this is true, can Bitcoin Core even claim to be a full node?
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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
48 views

What valid transactions are not broadcastable?

Many valid transactions are not broadcastable by default in bitcoin core to avoid attacks that could harm the network. These would rarely be found in a node's mempool but could, however, be found in ...
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1answer
149 views

How to verify if a transaction is signed correctly?

Given an arbitrary signed raw transaction, how can we easily verify if all inputs are correctly signed (assuming all inputs are existent/unspent and the fee is higher than zero)? Bitcoin core's RPC ...
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1answer
50 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
62 views

What kind of bug does bitcoin core possess that have to be replicated

In order to build a bitcoin client accepted by the current bitcoin nodes we to have to emulate the C++ code present in the bitcoin core client, with all its attributes even the bugs. For example the ...
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68 views

block verification cost

When a node receives a block, is it enough to validate root of Merkel tree ? How does block size affect the validation cost? What is the difference between the cost of validation 1mg-size block and ...
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92 views

Does each block contain all the Bitcoin transactions for that time period?

When a miner validates a block, does the block contain all transactions in Bitcoin for that time period? So does a miner validate an individual transaction between two parties, or are they validating ...
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57 views

How can a reciever verify that transaction data was not altered by 3rd party?

My scenario: My web server: - Generates private and public, and a wallet address from the public key for a user website account - Server can not connect to the outside (Can not connect to the Bitcoin ...
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1answer
116 views

When exactly do the transactions get validated?

I have some gaps in my understanding to the life cycle of the transaction that I want someone to help me fill them specially with the validation. What I understand about the life cycle with my ...
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177 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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How to Validate Signature with SigScript length 8b?

I created a raw Transaction: ...
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1answer
180 views

How to tell if a transaction is valid?

So I have been reading up on bitcoin and blockchain for awhile now, but I have yet to fully understand it. I understand that bitcoin leverage on DLT, which uses cryptography to verify transaction. ...
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1answer
92 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
63 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
61 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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47 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
51 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
80 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
114 views

Besides transaction validation, are there any other uses of the Script language in Bitcoin

Script's stack operations are used to validate signatures and scripts of transaction inputs and outputs. Is Script also used to validate block, network, or any other data? Seem like there are a lot ...
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39 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
86 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
105 views

How is a bitcoin transaction validated?

w.r.t. a bitcoin transaction, I am really struggling to understand how does bitcoin network validate that I 1) have the bitcoin that I want to send, and 2) haven’t already sent it to someone else. If ...
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1answer
48 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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593 views

When Schnorr signatures are part of Bitcoin will it be possible validate each block with only one signature validation?

In a recent talk Pieter Wuille talked about speed up verification when using Schnorr signatures and various algorithms for verifying multiple signatures. Would it really be possible to verify one ...
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1answer
158 views

Why every node needs to validate a transaction in Bitcoin

I am just understanding the Bitcoin network, and now understand that every block and every transaction is propagated to every node in the Bitcoin network (not sure yet the difference between full vs. ...
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1answer
85 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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1answer
191 views

How does a node decide whether a block is valid?

I'm a software developer, and I've been trying to figure out how a node decides whether a block is valid, I do understand the hashes in bitcoin, the merkle root, and all those aspects but my question ...
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432 views

Did the introduction of VerifyScript cause a backwards incompatible change to consensus?

My question is about the changes to bitcoin done by commit range [a75560d8, 6ff5f718], and their effect on consensus. Out of this range of four commits (all attributed to satoshi) during the dates ...
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91 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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1answer
88 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
222 views

Schnorr batch validation speed statistics

In this question Schnorr vs ECDSA I see in the Peter Wuille's answer the following comment about Schnorr signature batch validation: "Improving verification speed, by supporting batch validation of ...
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3answers
1k views

Block Validation: who does it? How much it costs? And is it present in all protocols?

Different threads were posted in order to clear up this question, but there are some points that I would need to confirm: When you become a full-node (NOT miner, you just downloaded the full ...
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1answer
457 views

Schnorr's batch validation

In the recent BIP about Schnorr's standardization, Pieter Wuille presents an algorithm for batch validation. In my understanding the most heavy operation is the multiplication by a scalar: to make ...
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1answer
216 views

How long does it take to validate a full block?

I'm interested to know how long does it take to validate a Bitcoin block on average home pc. I'm less interested in a precise number. I'm fully aware that it can be different between different ...
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2answers
224 views

How are blocks verified?

I see in the bitcoin wiki there is something called "script" which compiles down to some bytecode to be run by a very very basic virtual machine. Does this mean that each block is actually just a ...
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2answers
421 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
176 views

How does copying main stack prevent malformed unlocking scripts vulnerabilities?

https://github.com/bitcoinbook/bitcoinbook/blob/develop/ch06.asciidoc In the original bitcoin client, the unlocking and locking scripts were concatenated and executed in sequence. For security ...
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1answer
38 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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1answer
81 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
175 views

A couple of questions on Schnorr sig

In the BIP by Pieter Wuille it is told that the key prefixed version of Schnorr signature is needed when the scheme is used in combination with BIP32's unhardened derivation. Could someone provide an ...
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1answer
122 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
81 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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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 ...