Questions tagged [transaction-verification]

Refers to the process of checking the validity of transactions.

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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 ...
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1answer
602 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 ...
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2answers
364 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 ...
19
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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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4answers
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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 ...
11
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1answer
3k 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 ...
2
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2answers
203 views

Incentive for validating block

When miners find a solution to a block and broadcast it, what is the incentive for the other miners to actually validate that it is correct? It seems that they might save time by just starting to work ...
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2answers
4k views

How can transactions be verified without the private key?

Trying to get my head around her royal Bitcoin here... I understand that blocks of transactions are broadcast to the network, and that miners verify that the BC is 'spendable' by trawling the ...
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3answers
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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 ...
19
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1answer
34k 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 ...
4
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1answer
510 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 ...
2
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2answers
224 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 ...
5
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2answers
285 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
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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 ...
2
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3answers
407 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 ...
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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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4answers
21k 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 ...
6
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1answer
784 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 ...
3
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1answer
197 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 ...
6
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1answer
214 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 ...
4
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1answer
444 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
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1answer
246 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 ...
2
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1answer
358 views

Verification of transaction once trasaction is broadcasted

I have few doubts regarding verification of transaction and am trying to find answers from last few days. I agree similar post exist in this portal but I am not getting satisfactory answer for my ...
2
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2answers
300 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
421 views

Full list of "special cases" during Bitcoin Script execution (p2sh, p2wsh, etc.)?

When executing a Bitcoin Script, there are some "special cases" where the interpreter performs extra verification beyond just executing scriptSig and then scriptPubKey. For example, if the ...
4
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1answer
198 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
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1answer
795 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 ...
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2answers
10k views

How Blockchain transaction verification takes place?

How does each transaction verifying node come to know if the sender has enough amount in its wallet to transfer to the receiver or not? How are Blockchain transactions validated?
2
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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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2answers
475 views

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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1answer
1k views

Is a miner running a full node?

Is a miner just running a full node that is connected with the mining hardware? Or is there such thing as a miner node? Does it use additional software for transaction selection? Thanks in advance!
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1answer
149 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 ...
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1answer
284 views

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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4answers
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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 ...
5
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1answer
429 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 ...
3
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1answer
217 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. ...
2
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2answers
76 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 ...
2
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1answer
214 views

"Instantaneous" transaction verification?

Jan Moritz Lindemann graciously educated me that difficulty is used not only to regulate the creation rate of a cryptocurrency but also to allow for block propagation thus prevent orphaned blocks. ...
2
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3answers
551 views

Why can't someone create a valid digital signature without knowing your private key?

I understand from the following two posts that private keys are not displayed by the sender when getting their transaction validated by the bitcoin miners: What happens to Private Key on Payment How ...
2
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1answer
364 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 ...
2
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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-...
2
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1answer
180 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 ...
2
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4answers
221 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 ...
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2answers
200 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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2answers
737 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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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 ...
0
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2answers
2k views

how to do address callbacks?

I'm building a webapp that needs to update account info and send a message when an account's address gets a deposit, and/or confirm withdrawals. I'm not sure what the best way to do this is. Would ...
0
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1answer
284 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 ...
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2answers
199 views

Can an attacker use a modified Bitcoin node to pass fake transactions into the mempool?

Is it possible for a malicious attacker to download a bitcoin software code, modify that code and use that software for his own benefit? I know that any changes implemented in the bitcoin software ...
0
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2answers
201 views

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 ...