Questions tagged [transaction-verification]

Refers to the process of checking the validity of transactions.

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Bitcoin check if the transaction is valid

When a node receives a new transaction, that node will check if the one broadcasting the transaction has enough coins to initiate it. Bitcoin follows a UTXO model, therefore the node has to check in ...
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Clarification on the script P2SH, how is executed to Bitcoin core?

This question is a continuation of the my post yesterday. Today I have a question on P2SH execution so, an example of the script should be this OP_0 <A Signature> <B Signature> OP_2 <...
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How are bitcoin transactions and the blockchain transferred over the internet?

So I have several specific question connected to this topic and I'm aware of the conceptual answers and I'm only interested in the technical details (with programming terms and concepts as I'm a ...
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How does this simple script use the OP_CHECKSIG opcode?

I have this Script P2PKH <A Signature> <A Public Key> OP_DUP OP_HASH160 <A Public Key Hash> OP_EQUALVERIFY OP_CHECKSIG The bitcoin.org documentation say this The entire ...
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Bitcoin Signature Verification

I am trying to implement the OP_CHECKSIG opcode of Bitcoin and verify whether a signature is valid or not. I have the signature that I recieve from the transaction data and the public key(the hex ...
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Verifying a bitcoin Signature and what is the transaction data that is signed?

Given a bitcoin transaction where it is able to redeem it's UTXO's, how can I verify in Java if the signature is actually a valid signature or not. I was trying to use the Bouncy Castle library where ...
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How does OP_CHECKSIG work

Hi I am learning bitcoin and learning how scripting works and how to use P2PKH. I was wondering how does OP_CHECKSIG work. I want to understand what is the data that the private key signs to create ...
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How to prevent double spending Bitcoins?

If I create a transaction, my node will check my UTXO's and if i have enough BTC to do this transaction it will be mined. So let's say I want to spend 12 BTC to Anna. The System will check if i ...
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What happens to transactions included in extinct or invalid blocks?

I have read that a block contains several transactions. An attacker can forge fake a block. The blockchain is safe because the system will choose and keep the longest chain. So the fake block will ...
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Is verification of a blockchain computationally cheaper than recreating it?

One of the advantages of cryptocurrencies like Bitcoin that is often repeated is how hard it should be to manipulate past transactions. The reason that is often stated is that you would have to re-...
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How exactly do transactions work?

When I search for transaction in bitcoin I am able to find explanations which tell me that there are e.g. two persons A and B and A wants to tranfer a number of bitcoin to B. Imagine A wants to pay 2 ...
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Bitcoin transactions validation process

I have a general understanding of building blocks. But am hoping someone can fill in the details/gaps. Also, can you correct if something is not right? Thanks. Scenario: Bitcoin transactions are ...
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Following SegWit implementation, is BIP-146 signalling and implementation still on the docket?

Is BIP 146, which defines using the low S value, still on the docket to be signalled and implemented given that SegWit fixed the txid malleability issue by moving the witness outside the transaction? ...
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How does Proof of Stake prevents dishonest behaviour compared to PoW?

I know that in Proof of Work (PoW) once a node has found the solution (the nonce) they announce it to the network. Then the rest of the nodes can easily verify the correctness of the block hash and ...
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How can I calculate/estimate how quickly a machine can verify transactions on the blockchain?

If I have some machine with particular specs in mind (processor/memory/bandwidth), how can I estimate how quickly that node can download and verify transactions? In a quick search I wasn't able to ...
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How can I find the coinbase transactions where the bitcoins involved in a transaction were created?

I am exploring a transaction and if would like to know when was the money created, I guess I would end up with a lot of coinable transactions. For a certain transaction I could explore the previous ...
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Schnorr vs ECDSA

I understand that Schnorr signatures provide an improvement on ECDSA in that they are a fixed 64 bytes instead of the longer ECDSA sig format, however, I don't see how this is an advantage over ECDSA ...
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If I set assumevalid=0 after syncing the blockchain will Bitcoin Core go back and validate historical blocks?

I originally synced my node using the Bitcoin Core default assumevalid value. If I set assumevalid=0 in bitcoin.conf and restart my node, will my node go back and validate historical blocks?
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Bitcoin transaction fee calculator

I'm new to bitcoin. Is there a website where I can type amount of BTC I want to send and type of transaction - Urgent, Normal, Economic and they give me the price in USD how much the transaction fee ...
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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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Checking if a receiver has enough coins

How do miners verify the blockchain transaction history to check if the sender has enough money if the address can be changed at any time?
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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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Why are only specific transaction types accepted into the mempool?

In the Bitcoin Mainnet, only specific transaction types are accepted: Bitcoin uses a scripting language to specify (and satisfy) the encumbrances, thereby allowing a whole host of transaction types....
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Message: “this payment has not yet been transmitted”

My smartphone wallet samsung android with application bitcoin core version wallet 7.04 does not get paid. Message: "this payment has not yet been transmitted". from March 18 at 18:56 (NYC) I have ...
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Where is sum(vin) > sum(vout) check in Bitcoin Core?

I'm searching the function that validates a transaction according to Protocol rules - "tx" messages especially step 14 sum(vin) > sum(vout). I found this interesting function CheckTransaction(...
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Are transactions with the same ScriptSig a security problem?

For instance while looking at the transaction stack of my address, tracing it to exchanges I use, I came across this: https://www.blockchain.com/btc/tx/...
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Bitcoin checks and balances

When a new block is created, does each block need to be validated? How does it differ from validating transactions? Why miners would waste time validating transactions and blocks when they could ...
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Indexing of transactions in the blockchain

Say we have transaction T(1) from many years ago, at block height 125001; then a new transaction T(2), consuming all the outputs from T(1), comes up around block height 568720 (that's Today). There's ...
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Bitcoin fake transactions

Suppose, A and B are malicious attackers. Both want to send unlimited fake transactions to each other. I know that the transactions won't be accepted in the blockchain. In fact, they don't want their ...
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How to generate the digest from a raw bitcoin transaction for verifying signature of specific input?

I'm writing a stand alone process that needs to verify that a known UTXO is part of a new transaction with a valid signature. Inputs [ UTXO, raw transaction, input_number ] How do to I verify the ...
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Confirming transactions in the Merkle root and SegWit

I'm trying to find out how exactly transactions are confirmed in a block. I understand that to confirm a transaction, you hash it with its associated transaction and then the associated hashes until ...
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1answer
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How can block time and block size be fixed when transaction volume is constantly increasing?

As I understand it the network rejects blocks over 1MB, and block hash difficulty is set after each block is created as to keep the block time close to 10min. But if people are constantly joining ...
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How confirm my own doublespend transaction got confirmed

Transactions in the testnet are right now almost always double spent with a new txid (possible due to tx malleability). This is actually quite nice for testing purposes. So I'm wondering - when I ...
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How does transaction authentication between buyer and seller look for?

I am new to cryptography and would like to understand how a digital signature works between a buyer and a Bitcoin seller. How does transaction authentication between buyer and seller look for? Please ...
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On blockchain scalability bottleneck

It is often said that the major bottleneck of blockchain scalability is that every (honest) node has to process every (valid) transactions. But the progress of a blockchain is how fast it reaches ...
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Validate 3rd party transactions on Bitcoin-qt debug window

Is there a way to validate a random transaction via transaction ID on the debug window? Imagine I want to validate a transaction between 2 wallets I don't control. I believe its possible to check if ...
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P2SH secure spending. How?

Maybe my question is stupid, but imagine that I'm trying to spend inputs from p2sh. For example, p2sh scriptPubKey looks like: OP_SHA256 ...
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Why are the inputs of Bitcoin transactions signed?

This is my understanding of what a transaction looks like: inputs: input0: txid: <funding tx0 TXID> outputID: <output ID of UTXO in the funding tx0> scriptSig: <...
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API for getting the Hash-of-thing-to-sign

Does anyone have, or have access to a simple API that can calculate the hashofthingtosign for old transactions along the blockchain? I'm just looking for something simple to see what the "...
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How are 'Not Mineable ' cryptos able to verify transactions?

NEM, Stratis, BitShares are 'non mineable' cryptocurrencies. How do they verify transactions if there are no miners? Maybe nodes only? Or... what am I missing here? I ask because I assume with a non ...
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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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Is it posible to create a transaction output that can either be reddemed by privK of Addr A or by privK of Addr B AFTER certain blockheight?

I am thinking about how to secure your Bitcoin savings. One idea I had was to create sort of a "backup" address B for an address A which stores the bitcoins. So what I want to achieve is that you ...
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When do scripts executed?

Can anyone explain when does a script executed exactly? There are several information about "how scripts are executed" but no information about "when".
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How does blockchain technology handle the actual transaction data?

My understanding of how a transaction is secured in blockchain, especially in bitcoin, is that the output of transaction data is locked to the recipient's address (a shorter version of his public key)....
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May it be a risk to use the origin as the change address?

Follow scenario: The balance of my origin address is 1 BTC. I'm transfering 0.1 BTC to a shop where I'm buying some goods, my wallet returns the change to my origin address. Now my origin address has ...
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How do you get Sibling Hashed Values in a Merkle Proof?

Merkle Proofs are one of the main reasons that people attribute Bitcoin's use of Merkle Trees. But I'm struggling to understand how these work in practice. Please explain theoretically as well as ...
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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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When a node receives a transaction, what steps does it do to verify that transaction?

I know that it verifies the block hash by calculating each hash of the contiguous blocks in order, but does it verify the balance of each wallet sending the transactions as well? And does it do the ...
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How miners validate each transaction?

There is a locking to each transaction? and sender also attach his digital signature to that transaction? When this transaction comes to miners then how they validate this transaction is valid. ...
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how do miners verify transaction without identifying sender and receiver?

I mean in satoshi paper we read sender and receiver have limited anonymity. By keeping public keys anonymous. The public can see that someone is sending an amount to someone else, but without ...