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Questions tagged [transaction-id]

The unique identifier of a transaction corresponding to the sha256d hash of the transaction.

68 questions
25
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1 answer

What is Transaction Malleability?

The Bitcoin exchange MtGox has stated in this press release that "transaction malleability" caused them to stop sending bitcoins. A recent question asked if it really is an issue. But what is transaction malleability in the first place?
user6049
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2 answers

How can I avoid transaction malleability consequences?

Please note that this question is NOT a duplicate of other questions regarding transaction-malleability. My question is regarding a following scenario, that could happen on an exchange that uses on-chain wallet management: user deposits funds on…
mav
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8
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1 answer

What happens when two txid's collide?

Let's suppose that I can create SHA256d collisions, and I use this ability to create two transactions that have the same hash, A and B. These transactions are not the same, but they hash to the same value. I submit transaction A to the network, and…
Nick ODell
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8
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2 answers

How do I calculate the txid of this raw transaction?

I'm trying to parse a bitcoin block using Python. I called getrawtransaction over JSON-RPC. I got…
user21322
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6
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2 answers

What would be the fastest way to query for a certain txid to get its inputs?

I am working in an artistic/visualization project that analyses Bitcoin transactions. I have a Bitcore instance with insight API and from a Python script I query through the REST API so the queries are returned in json format. For the project I use…
muimota
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5
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2 answers

Why didn't Bitcoin implement segwit in the first place?

Why didn't Bitcoin implement segwit in the first place? Why and how does non-segwit Bitcoin enable a miner to change a transaction's txid? From Mastering Bitcoin ch. 7 § "Transaction identifiers": Before segwit, transactions could have their…
Geremia
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5
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SegWit and previous hash: txid or wtxid, or either?

With segwit there will be two transaction ids wtxid and txid Can either one of them be used as previous hash or only txid?
Albert S
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5
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1 answer

Duplicated hash values in mining reward

This transaction is contained in two MainChain-Blocks: https://blockchain.info/tx/e3bf3d07d4b0375638d5f1db5255fe07ba2c4cb067cd81b84ee974b6585fb468 On Blockexplorer there is a note of this…
Dennis Kriechel
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4
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1 answer

How to compute SegWit txid?

BIP141 says wtxid is SHA256 of [nVersion][marker][flag][txins][txouts][witness][nLockTime]. Is data that hashed as txid includes witness? And will txid be presented in block, e.g. be counted when building Merkle tree?
fjchen
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Compute TxID of Bitcoin Transaction

Originally posted to StackOverflow but with no response. Thought I might have better luck here. I've successfully created a Bitcoin transaction in C# according to the protocol specifications. Here's the transaction in…
Festus Martingale
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4
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1 answer

Pairing pattern of txids in merkle tree

For constructing the merkle tree txids are paired and hashed. ¹ But how are these txids paired? Does it happen chronologically or is there a certain pattern of pairing?
Aliakbar Ahmadi
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4
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3 answers

Duplicate tx ids

Is there a quick and dirty way to detect all transactions whose tx-id can be found in more than one transaction since the genesis block? I would also like to see mutated transactions as well although I am not sure if the blockchain keeps a…
Doug Peters
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2 answers

Why does txID generation consider signatures?

I've been reading a lot about transaction malleability, and noticed that the only way to achieve it is by altering the transaction signature/s. Why does the protocol even consider the signature in the payload for SHA256? The protocol should only…
masize
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How to calculate txid for segwit transactions?

I'm having difficulty calculating txid for recent transactions. I followed bip-141 at https://github.com/bitcoin/bips/blob/master/bip-0141.mediawiki For the first transaction in the first block found in blk00165.dat (testnet), I get the following…
fon
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Question about identical txids/merkle tree in Developer guide

I am new to the technical details about Bitcoin and has been reading Developer guide on bitcoin.org. I have a question about below contents mentioning merkle tree, identical txids. I googled and searched here but seemed to be no answer. Note: If…
Olivia Zhang
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