Questions tagged [transaction-verification]

Refers to the process of checking the validity of transactions.

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21
votes
3answers
5k 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
32k 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
18k 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 ...
9
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1answer
1k views

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
2k 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
17k 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 ...
7
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2answers
2k 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 ...
6
votes
1answer
252 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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4answers
905 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 ...
6
votes
1answer
661 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
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1answer
198 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
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1answer
207 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
371 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
1answer
589 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
81 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 ...
4
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3answers
671 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
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
votes
2answers
102 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 ...
4
votes
3answers
11k 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
237 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
228 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
2answers
392 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
1answer
362 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
620 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
218 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
1answer
435 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
776 views

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

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
691 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
7k 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
215 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 ...
3
votes
3answers
259 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
888 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
193 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
189 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
843 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
174 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
518 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
367 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
368 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?
2
votes
1answer
185 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
131 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
2answers
674 views

Difference between transaction chain vs blockchain

What are the difference between transaction chain in bitcoin and blockchain used in bitcoin? Is it sufficient to say to each transaction refers to previous transactions in the transaction chain and ...
2
votes
2answers
625 views

How does the computational cost of verifying transactions scale with the number of total transactions?

As more transactions are added to the block chain, does each individual transaction (ie. I send a bitcoin to a friend) get more expensive (in terms of FLOPS) to verify and commit to the chain? If each ...
2
votes
2answers
218 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:/...
2
votes
1answer
87 views

How are past transactions validated (when there have been softforks)?

Let's say I run a bitcoin client for the first time. It downloads a copy of the blockchain from the very beginning and starts validating all the transactions included in all the blocks. Since there ...
2
votes
2answers
348 views

Confirm own incoming transactions

Is it possible to only mine your own incoming transactions? So you can confirm a Bitcoin transaction (only locally).
2
votes
1answer
40 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 ...