Questions tagged [transaction-verification]
Refers to the process of checking the validity of transactions.
222
questions
0
votes
1answer
37 views
how does bitcoin solve the same chain replay attack?
Let's say I send 10BTC to Bob. I have 30 BTC. So after transferring, I should have 20.
Now, after I transfered 10, transaction can be copied and broadcasted to the network again by Bob(he might have ...
1
vote
1answer
34 views
Do full nodes store the complete merkle tree or do they regenerate it when creating a merkle proof?
I understand what the merkle root is for. And I understand that blocks don't store the merkle tree.
Question 1) Is there any place that the complete merkle trees get stored? I don't mean the merkle ...
1
vote
1answer
39 views
Is this Merkle hash root problem existent in Bitcoin?
In the Wikipedia article about Merkle trees, I was just reading this, unable to understand where the problem lies:
Second preimage attack
The Merkle hash root does not indicate the tree depth, ...
1
vote
2answers
119 views
What's the blocksize limit after segwit and how do legacy nodes deal with segwit transactions?
Normally, I heard that the bitcoin blocksize is 1MB, but with the Segwit update the blocksize can be up to 4MB, so we should say that the blocksize is 4MB, right? Moreover legacy nodes only receive ...
1
vote
2answers
37 views
Time allowed to a node to react to verify a transaction and number of verifications?
Do the person acting as full nodes have to be active and online around for a particular decided time, like a job where you have to be around your machine because a transaction for verification can pop ...
1
vote
1answer
59 views
How do SPV clients acquire transactions from other nodes and verify that they are part of the blockchain?
I explored SPV clients as a subject from a lot of different resources, but there are a few of things that are keeping me confused:
I found out that SPV clients have no mempool even though SPV clients ...
0
votes
0answers
15 views
How are transations validated? [duplicate]
As per my understanding whenever someone sends a bitcoin it gets added to the transaction pool. The miner then take these transactions from the pool and add it to the block. However, I wanted ...
1
vote
1answer
72 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 ...
2
votes
3answers
85 views
Basic question about transaction verification
I am fairly new to crypto and had some questions about how transactions are verified by the nodes
Would it be correct to say that the full nodes check to see if the sender(Alice’s) signature is valid. ...
1
vote
1answer
54 views
What can I do with “unspent” transactions? Can I transmit them to a chain?
I withdrew some bitcoin from a service's account I maintain. The transaction shows up in my wallet, but it has been marked as "unspent" ever since. What does this mean?
0
votes
2answers
45 views
Why is 'script' used in a transaction instead of the output address?
I see transactions contain script for each output, but this "script" seems to be deterministically derived from the address associated with the output.
Why does the bitcoin protocol opt for the use ...
0
votes
0answers
45 views
Unspent bitcoin transaction
So about two weeks ago i sent bitcoin to a friend, and it was confirmed but in the summary it was listed unspent, he claimed not to have received. I was really confused since then, now this morning i ...
7
votes
1answer
467 views
Why is there no such thing as a redirected, forged, or fake transaction?
In the past, we had numerous questions about "fake" or "forged" transactions. Such transactions could supposedly be created even without holding any bitcoins, yet would end up in the mempool or even ...
2
votes
4answers
161 views
If two parties submit a conflicting transaction between each other, how does the network decide which one is correct?
Let's say parties A and B both submit a transaction to the blockchain with a different version of what happened. Party A submits a transaction saying Party B gave him 3 BTC and Party B submits a ...
4
votes
0answers
82 views
How many bitcoin transactions can be verified per second on commodity hardware in 2020?
I am trying to figure out how many Bitcoin transactions could be verified per second.
Am I correct that signature verification is more expansive than computing Merkletrees and hashes and constitutes ...
0
votes
1answer
33 views
Is there any open source tool to verify segwit transaction without publishing it?
I have created below transaction:
...
0
votes
1answer
37 views
Given a Bitcoin transaction as JSON data, how can I determine the number of confirmations?
According to blockchain.info, 4,198 confirmations have been received on the following Bitcoin transaction at the time of this writing. Give then following Bitcoin transaction as JSON (ref: transaction ...
0
votes
1answer
53 views
Is it possible to skip verification of blockchain data when using bitcoin core?
Because I need bitcoin core client only for JSON-RPC requests. Will I need pruned initialization or normal initialization of bitcoin core client for successfully running such requests? (I guess client ...
0
votes
1answer
37 views
How do people using thin clients know the correct merkle path of transactions they've sent without knowing the full block?
User A send a transaction to user B. Those transactions are bundled together into a merkle tree. User A and B can both use the transaction plus the merkle root, plus the merkle path to prove the ...
2
votes
0answers
50 views
Transaction validation cost
what relation is between transaction size or a number of input and validation cost? for example, It's o(n) or o(n^2)?
0
votes
0answers
131 views
Bitcoins stuck in memory pool [duplicate]
I sent my 0.1 bitcoin on the 8th of January from an offline wallet (Bitcoin Core), to an online wallet. Still haven't got the btc in my new wallet. The status on the offline wallet says: "unconfirmed, ...
1
vote
2answers
71 views
How do nodes validate that a UTXO in a new transaction is unspent?
Does it check every block in between where the UTXO first appeared and the current time to make sure it didn't get spent then? Or is there some other caching or other method to make the check faster?
0
votes
1answer
48 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 ...
4
votes
1answer
51 views
At what block height may locktimed transactions get included?
Transactions with outputs whose sequence is smaller than UINT_MAX are interpreted as locked until the timestamp or block height specified in nLockTime is reached.
Specifically regarding the block ...
1
vote
3answers
292 views
Get transaction data from full node
Background Information
I am building an application that requires the ability to query any bitcoin full node (from a python script using raw tcp sockets) in order to read the OP_Return value listed ...
1
vote
1answer
51 views
Can attackers change transactions during a 51% attack?
If in a 51% attack transactions can be reversed, isn't it possible that the chain with more hash rate also changes transactions (for example if x sent 5 btc to y, they would change it to x sent 500 ...
0
votes
1answer
58 views
How to verify locking and unlocking scripts?
I've selected an arbitrary transaction id and retrieved its associated transaction details using the blockcypher explorer as follows:
from blockcypher import get_transaction_details
...
0
votes
2answers
141 views
Verify Bitcoin Transaction
Following the great post [Redeeming a raw transaction step by step example required, I came up with code below but the verification failed.
// pubkeyBytes, len: 65
// ...
0
votes
2answers
64 views
Sent BTC from Coinbase, blockchain explorer says Confirmed. Is recipient lying or could something else be the issue?
Sent BTC (approx $500) from Coinbase, Blockchain explorer says Confirmed. Is recipient lying they have not received or could something else be the issue such as his wallet?
Recipient says it could be ...
0
votes
1answer
40 views
What stopping miner from altering value in transaction to increase transaction fee?
I'm learning bitcoin through this book "Mastering Bitcoin, 2nd Edition by Andreas M. Antonopoulos". I'm at Chapter 6 "Transactions".
Here is my doubt:
Example there is node A, received transaction ...
0
votes
1answer
76 views
Not able to Spend 2-2 MultiSig UTXO
I created 2-2 Multisig Account 2NECouPA4UVNMzX1K7kekc4W3VudDhMdFkM from msrFNhKwLu9GrT3hFoizz21xEwJ61xMsym and n1NPFEJHBA8j63B5dgJ3aQcufA8VmrN27U, I tried spending UTXO from this account but got an ...
1
vote
1answer
85 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. ...
1
vote
1answer
122 views
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 <...
0
votes
1answer
116 views
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 ...
0
votes
1answer
117 views
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 ...
0
votes
1answer
91 views
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 ...
2
votes
1answer
289 views
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 ...
2
votes
1answer
501 views
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 ...
2
votes
1answer
64 views
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 ...
1
vote
3answers
221 views
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 ...
1
vote
2answers
408 views
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-...
0
votes
1answer
45 views
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 ...
2
votes
1answer
33 views
What does “Green address verification” mean in the context of transaction validation?
I am only new to Bitcoin and I would like to know what a "Green address verification" is. I have an Electrum wallet ver 3.3.6 and I think the term is being used in the context of faster transactions ...
0
votes
3answers
100 views
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 ...
0
votes
1answer
39 views
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 ...
1
vote
1answer
55 views
Can anyone initiate a Blockchain transaction into the mining pool?
Let's say user A has public key P and corresponding private key P'. Can someone else initiate a transaction for public key P with some wrong private key, let's say P''? Once this goes to the memory ...
4
votes
1answer
576 views
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?
1
vote
1answer
83 views
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? ...
1
vote
1answer
104 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 ...
0
votes
2answers
117 views
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?
