Questions tagged [transaction-verification]

Refers to the process of checking the validity of transactions.

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23
votes
3answers
6k views

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 ...
18
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1answer
33k views

How do nodes verify Bitcoin Transactions?

I am trying to understand the role played by various nodes in the Bitcoin Network in verifying the transactions that are taking place in real time. I think that I understand the process of Transaction ...
17
votes
1answer
2k views

How is SegWit a soft fork?

Reading this section of BIP144, I noticed the followng statement: Parsers supporting this BIP will be able to distinguish between the old serialization format (without the witness) and this one. ...
13
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4answers
19k views

relationship between bitcoin miner and verification of transactions [closed]

Bitcoin miner mines a block, which can't be submitted to the network without proof of work. And the new block contains all of the new transactions. Hence the new block acts as a security measure, and ...
11
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1answer
2k views

What are the advantages of 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 ...
8
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3answers
3k views

If Bitcoin transactions require ~10 min to clear, how can payments get recognized within seconds?

Bitcoin Monitor offers to issue a notification moments after a payment is sent to a Bitcoin address. Yet if Bitcoin transactions require ~10 min to get written into the blockchain and confirmed as ...
8
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4answers
18k views

Why is mining necessary for the Bitcoin network/system? [duplicate]

I understand that a transaction is a record of 1+ Bitcoins being given from one party to another. I understand that a block is a collection of unverified (pending) transactions that gets verified ...
8
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2answers
3k views

Different error messages under “Mandatory script verify flag failed.”

I've been playing with raw transactions and signed transaction and I've noticed that the error "Mandatory script verify flag failed" comes in two variations. script failed on OP_EQUALVERIFY OP Script ...
7
votes
4answers
991 views

Is it possible to add a transaction input to a transaction in the mempool?

Is it possible to add an input to a transaction that is in the mempool? For example, if someone is paying 1 BTC to their friend, I can get the raw hex data of this transaction from the mempool before ...
7
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1answer
468 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 ...
6
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1answer
268 views

Is the SPV client model scalable?

SPV clients typically connect to full node peers and set filters on what information they download. How many SPV peers can a single full node support, typically? Is it reasonable to expect millions ...
6
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1answer
715 views

Transaction verification by miner VS full node with & without SegWit

I'm trying to fill a few gaps in my understanding of transaction verification and would appreciate any insight. Without SegWit Miners broadcast new blocks which contain the signature(s) with every ...
6
votes
1answer
201 views

Does every full node verify every transaction TWO separate times?

I am building my Bitcoin expertise, and want to verify my understanding on a specific point: at what point(s) do all full nodes verifies a new transaction? Here is my understanding in a nutshell, ...
6
votes
1answer
212 views

What happens in detail, when Bitcoin Core verifies a block during synchronization?

Since version 0.10.x, block headers are acquired separately, and therefore download is not delayed until previous blocks have been verified. Previous questions about synchronization mention that the ...
5
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3answers
1k views

Do miners have to hold all the blocks in memory?

Running a miner node, one would have to verify transactions. This includes checking all the inputs of all the transactions. Does this mean that a miner must hold all the block-chain in memory (...
5
votes
1answer
409 views

Where the P2SH script gets written?

I understand that when I'm doing a transaction, I'm locking those bitcoins to whoever provide the solution to a script that has the hash I posted. But, where does the hash get written? I would ...
5
votes
2answers
159 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 ...
5
votes
1answer
748 views

What is an “insecure transaction type”, as mentioned by Bitcoin Wallet for Android?

I am running Bitcoin Core v0.11.0.0-gd26f951 (64-bit) at home on Ubuntu, and have installed the Bitcoin Wallet for Android on my phone. I sent two transactions from home to my phone: First, Second. ...
5
votes
1answer
95 views

Can corrupted unspent transaction outputs list leading to higher than expected fee be seen as an actual threat?

Let's imagine, an attacker managed to corrupt your local list of unspent transaction outputs (or a blockhain explorer you use) in a way that certain unspent transaction outputs seem to hold less coins ...
5
votes
1answer
243 views

Why do bigger blocks make it more expensive to run a full node?

Does it cost more storage? For the transaction verification, to which extent bigger blocks make it more computational intensive? In terms of computational complexity, is the verification process a O(n)...
4
votes
3answers
677 views

How do miners understand what a transaction does?

Bitcoins are spent via transaction scripts that can be quite complicated. How do miners understand what a transaction does? A miner has to decide whether to include a transaction in their block, but ...
4
votes
1answer
593 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?
4
votes
1answer
1k views

Transaction's maximum size

Is there a maximum size for any given transaction? I just created this tx: http://blockexplorer.com/testnet/tx/194173dcc07b396433d5725abe76d52b10d42ebd3d1d10b465429f87fee12a52 and although it ...
4
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1answer
53 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 ...
4
votes
3answers
12k views

How do I lookup the details of a transaction, given the transaction ID?

I transferred BTC from GDAX to Binance. I have the transaction ID. How do I find out the status of the transfer. GDAX reports transfer complete. Thanks.
4
votes
1answer
240 views

walletnotify and transaction malleability

To monitor inbound payments for a web wallet, I plan to use walletnotify to record the transaction IDs, then on each blocknotify I will check the number of confirmations for each pending transaction. ...
4
votes
1answer
255 views

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 ...
4
votes
2answers
435 views

Bitcoind transaction data verification

I find myself a victim of either my poor googling skills, or the lack of detail in the bitcoind docs. I have a walletNotify script running on a full node that whenever a transaction to / from my ...
4
votes
0answers
87 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 ...
4
votes
1answer
425 views

How to calculate signature generation, signature verification, transaction verification speed?

I read this post on Bitcoin Scalability. As far as I understand sequence of steps in Bitcoin, simplified version of performing transaction should be following: On Sender's side: Create transaction ...
3
votes
3answers
818 views

How it is possible to validate existing Pay to Public Key Hash transaction without public key?

These are my understanding or assumptions. Sign a document requires secret key and message only as below SignDocument(secret key, message) => signature And verification of signature requires ...
3
votes
3answers
221 views

What if the execution time for an alt coin script exceeds the block time?

I don't know when and how often a script is executed, but it seems to me that there would be a problem if a single script (or a sum of all scripts in a block) exceeds the time it takes to be included ...
3
votes
3answers
14k views

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 ...
3
votes
1answer
506 views

What if is there is no solution to a block?

Please let me know if I understand something wrong. Let's say I want to create a new block and verify previous transactions. To do this, I need to: Choose which transactions I want to include in my ...
3
votes
1answer
782 views

Ethereum - how is the output of a contract computation verified? [closed]

This may be as simple as a pointer to some place in the docs I've missed, but how/where is the output of a contract's computation checked, or assured against a malicious miner with an intentionally ...
3
votes
1answer
711 views

Why does the Bitcoin core client use so much CPU time while synching?

I have always noticed the huge increase in cpu usage when I opened my client for the first time in a few days. I was wonder what this is from? I would imagine verifying all of the signatures of the ...
3
votes
3answers
400 views

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 ...
3
votes
1answer
1k views

Verifying a bitcoin trx on the Unix cmd line with OpenSSL?

I want to use openssl on unixoide systems to verify a transaction. I step on errors, when trying to verify a bitcoin trx’s hash. Here I am working on Mac OSX and OpenSSL (1.0.2a 19 Mar 2015). I know ...
3
votes
1answer
221 views

Is there any way to send an output to a script which can then only be sent to one of two addresses?

Is the following scenario possible? I want to send money to a script. This script will require knowing a private key to spend, as usual, but the script is only valid if the money is being sent to one ...
3
votes
1answer
192 views

Exhaustive technical explanation of signing & verification

I apologize for such a noobish question and am ashamed that I'm not getting this yet, but I can't seem to put together all of the pieces. I've read every question I can find on the subject, the ...
3
votes
1answer
1k views

Error validating transaction using BLOCKCYPHER

I recently followed the steps on the answer by StephenM347 to the following problem: Cannot access my bitcoins because my wallet is still synchronising. What can I do to spend them immediately? ...
3
votes
1answer
179 views

How are transactions verified to ensure only the eligible person can spend a Bitcoin balance?

I know each user has a public key and private key. The users signs the transaction with his private key and sends it to a Bitcoin address. What prevents me from claiming his coins? I read something ...
3
votes
1answer
523 views

What are the requirements of a transaction being included in a block?

What are the requirements of a transaction being included in a block? How does a miner verify that a transaction meets such requirements?
2
votes
3answers
387 views

Does the version prefix of an address force the type of transactions the address may treat?

A Bitcoin address is created with Base58Check encoding and it requires a version prefix, such as 0x00 for a P2PKH(pay-to-public-key-hash) address, 0x05 for a P2SH(pay-to-script-hash) address. Does ...
2
votes
1answer
188 views

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(...
2
votes
2answers
1k views

How can a miner verify that a UTXOs is not spent elsewhere?

How does a miner verify that a UTXO is not spent somewhere else, wouldn't he have to search the entire blockchain from that UTXO and onwards to see if this was the case? Assuming any real scale this ...
2
votes
3answers
135 views

When to check for confirmationsl

When monitoring incoming transactions for a web wallet, should I check for confirmations on a timer, e.g. every minute? Or should I check once every block by using blocknotify?
2
votes
3answers
92 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. ...
2
votes
1answer
309 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
2answers
250 views

Which kinds of transactions show quadratic signature-hashing scaling?

It has been stated: A major problem with simple approaches to increasing the Bitcoin blocksize is that for certain transactions, signature-hashing scales quadratically rather than linearly. https:/...

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