Questions tagged [transaction-verification]

Refers to the process of checking the validity of transactions.

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545 views

Why does only the earliest transaction matter for double spending?

On page 2 of Bitcoin paper, it says: The problem of course is the payee can't verify that one of the owners did not double-spend the coin. A common solution is to introduce a trusted central ...
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1answer
129 views

How does CoinJoin affect the total transaction size?

As I understand it, CoinJoin is a method to aggregate multiple transactions into a single transaction, mostly for privacy purposes. How does this aggregation affect the total size of the transactions?...
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1answer
169 views

Can arbitrary transactions be aggregated?

Is it possible to take multiple transactions in the form: [A->X] , [B->Y] , [C->Z], where A,B,C,X,Y,Z are arbitrary, unrelated Bitcoin users/wallets and aggregate them to a single transaction: [...
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219 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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1answer
1k views

When creating a transaction, how can you prove that you own your address without exposing your private key?

I'm trying to understand how Bitcoin works under the hood, but there's something I don't get at all, and can't find it. Suppose I own address A (I have the public key, A-public, and the private key A-...
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1answer
32 views

Which sender is banned in case of nvalid transactions or blocks?

When a node receives an invalid transaction or block, as far as I know, it bans the sender for 24 hours. However, I didn't exactly get which sender is banned. Is it the neighbor node that provides the ...
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1answer
431 views

why verification of transaction after proof of work?

I have question about bitcoin protocol. In Satoshi's paper it is mentioned that: New transactions are broadcast to all nodes. Each node collects new transactions into a block. Each node works on ...
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2answers
532 views

Does an Invalid Transaction persist in the mempool?

My basic understanding is that a transaction will continue to exist in the MemPool until it can be completed, (or eventually gets evicted due to the size of the MemPool). To me, this leads to a ...
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1answer
188 views

What happen to my bitcoin

I have payed last april 21 and april 25 should be my payment but it took days already here is my transaction id b5a9cb6a67429ec60c51f3aa197bec67af0003c841890132051f9fea40f71f76 And the same as april ...
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1answer
328 views

How does a non-upgraded node read a SegWit transaction? [duplicate]

I'm trying to understand how my node would interperet a SegWit transaction if I do not upgrade. Even if I do not upgrade, I should be ...
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1answer
72 views

tx-malleability who re-signed the tx?

It would be really great if there was a way to loop through all the txids in a new block and be able to check if you (can) sign your original transaction the same way it was re-signed - that it ...
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2answers
171 views

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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923 views

How does merkle tree verification of transaction work?

From what I have read, suppose B sends 1 bitcoin to C. C wishes to verify B's payment and asks C for the block number (location) that input transaction is located at. (Is this correct understanding/...
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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 ...
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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. ...
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1answer
172 views

How can I work out why a transaction isn't being included in any blocks? [duplicate]

I've crafted a testnet p2sh address using python-bitcoinlib. The script contents is 2-of-2 multisig: 2, key1, key2, 2, OP_CHECKMULTISIG Redeem script: ...
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136 views

Double spend a tx output already spent but unconfirmed because of low fee

In the protocol rules for validating transactions it says: Rule 9: For each input, if the referenced output exists in any other tx in the pool, reject this transaction.[5] I assume that when a ...
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1answer
532 views

Bitcoin testnet3: unable to push/publish raw transaction: how to verify validity of transaction?

I have created a raw transaction and am now trying to push the hex format into testnet3. I have used following two ways and both are giving me two different errors, first one: curl -d '{"hex":"...
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293 views

Who pays for the computational cost when validating a transaction

Suppose Alice wants to validate a transaction (check this transaction does exist, not make a new transaction), and suppose her has not downloaded all transaction history. My understanding is, 1) ...
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3answers
3k views

How does the Bitcoin Network verify whether the wallet has enough bitcoins for the transaction?

How does the Bitcoin Network verify whether the wallet has enough bitcoins for the transaction? I understand that it is verifiable by scanning the entire blockchain and see whether the wallet has the ...
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3answers
260 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 ...
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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 ...
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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 ...
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3answers
1k views

What counts as verification or validation of a transaction?

I understand the general ideas and properties of the block chain, but have not been able to understand how a transaction is created and gets to be verified or validated.
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1answer
502 views

Signing tx with OpenSSL, but fails when sending with bitcoin qt. How to debug?

I try to create a tx with 4 inputs, and sign it via cmdline and openssl on a cold storage machine. Then I want to send it via bitcoin qt (or blockchain.info). Signing with a single input and a single ...
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1answer
69 views

separating proof of work from mining possible?

I (think to) understand that proof-of-work is the process through which transactions are verified and the health of the network is being ensured. I also (think to) understand miners get bitcoins for ...
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1answer
63 views

What information about a transaction can be assumed accurate before confirmation?

When sending a Bitcoin transaction, what information in that transaction can be assumed to be accurate before receiving a confirmation? Can you verify the from address? Can you verify that the ...
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1answer
186 views

Verify value of input address

Think about a bitcoin transaction: Inputs: Address1: 2 BTC, Address2: 1 BTC Output: Address3: 3 BTC So the value of Address1 is because of two previous transactions where every one of those 2 ...
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3answers
97 views

How do Bitcoin and Colored Coin react to malformed transactions?

I need some help to clarify Bitcoin and colored coin mechanics. Are the assumptions below correct (and complete)? If an error (maybe a fraud) is presented in a Bitcoin transaction, nodes (including ...
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1answer
142 views

Does a new nodes verify all transactions or only blocks

When a node downloads the genesis and all blocks, does it verify all past transactions, or just the blocks (eg check the nonce/hash relation, thereby assuming the containing transactions must be right?...
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1answer
897 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 ...
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190 views

How are transaction fees claimed from a technical point of view?

A typical transaction has one or more inputs and one or more outputs. Since there is no amount specified for inputs, the rule is that ALL of the inputs is always transferred. Any discrepancy between ...
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672 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 ...
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1answer
63 views

Will Bitcoin remember unperformed transactions?

Let's say I transfer 0.05 BTC from 1 input to 1 output and don't pay a fee. If there are 6 blocks per hour, this means that my input has to be 369 hours (about 15 days) old so no fee is required. Let'...
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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).
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1answer
493 views

What is the memory usage for checking transaction inputs?

Whenever a transaction is received by a node, the node verifies its validity. To that end, it checks for each transaction input whether that input is part of the UTXO set. It is my understanding that ...
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180 views

Do Bitcoin miners verify validity of merge-mined Namecoin blocks?

I've been reading a little about merged mining as used in Bitcoin and Namecoin. It seems like merged mining effectively eliminated Namecoin-only mining pools, right? Since Namecoin-only pools are ...
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489 views

How is it possibile to verify payments without running a full network node?

I've read the Nakamoto's paper "Bitcoin: a peer-to-peer electronic cash system". In paragraph Simplified Payment Verification he said that is possible to verify payments without running a full network ...
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1answer
596 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. ...
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1answer
373 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 ...
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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)...
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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, ...
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2answers
276 views

I Want To Confirm That My Bitcoins Are Being Held In New Wallet

I sent a couple bitcoin from one of my trezor wallets to a different trezor wallet. I don't know the details about how bitcoin "sending" between wallets work, and now I feel the need to confirm that ...
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1answer
363 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 ...
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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 ...
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1answer
777 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 ...
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1k views

OP_CHECKSIG signature hash type 0

On the Bitcoin Wiki's OP_CHECKSIG documentation: Firstly always this (the default) procedure is applied: the public key and the signature are popped from the stack, in that order. If the ...
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82 views

How to send an invalid transaction for testing purposes?

How could I send an invalid transaction—for testing purposes, such as with testnet or regtest? For example, I would like to to try to double-spend, spend non existent coins, etc.
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317 views

How instantaneous is a Bitcoin transaction?

How quick does a bitcoin transaction happen? (assuming that both parties are online at the time) I read somewhere on the Internet that it's not recommended to accept a bitcoin payment right away (...
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256 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 ...