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Questions tagged [transactions]

This tag should be used for questions related to transactions. Transactions are signed messages regarding the transfer or generation of bitcoins. They are broadcast throughout the Bitcoin network and, if accepted, integrated in the blockchain.

128
votes
10answers
290k views

Why is my transaction not getting confirmed and what can I do about it?

I sent a transaction without (or with an exceptionally small) transaction fee using extremely small or unconfirmed inputs while the stars were not standing right. For whatever reason, I have been ...
46
votes
3answers
8k views

How does change work in a bitcoin transaction?

It seems that when you send a bitcoin transaction, all the coins in the sending address are spent in that transaction, divided into the amount that you intended to send, and "change", which goes back ...
61
votes
3answers
23k views

How to redeem a basic Tx?

Given a raw, standard Tx (wiki): 01000000 01 26c07ece0bce7cda0ccd14d99e205f118cde27e83dd75da7b141fe487b5528fb 00000000 8b ...
60
votes
9answers
24k views

How anonymous are Bitcoin transactions?

I read some sources that say Bitcoin transactions are anonymous, some that say they are semi-anonymous, and some that say they are not anonymous at all. In what ways are the transactions anonymous ...
33
votes
3answers
28k views

Who gets Bitcoin transaction fees?

Whenever I send bitcoins from one wallet or one exchange to the next there is always a fee. This makes sense with the exchange sites, they are just collecting the fee so they can make a living. What ...
50
votes
6answers
51k views

What is the Merkle root?

The Bitcoin wiki Vocabulary article explains why the Merkle root exists: Every transaction has a hash associated with it. In a block, all of the transaction hashes in the block are themselves ...
21
votes
2answers
13k views

Redeeming a raw transaction step by step example required

I am looking, specifically, for a step by step example transaction of sending Bitcoin which uses an actual transaction (How To Redeem A Basic Txn, from a few years back, does a great job of outlining ...
38
votes
2answers
5k views

What is the coin selection algorithm?

When creating a transaction in the standard client, what is the algorithm used to determine which unspent outputs will be used as inputs? Has this changed since the first version? What different ...
41
votes
3answers
11k views

Why does Bitcoin send the “change” to a different address?

For example I have an address (A) with 20 BTC and send 9 BTC to address (B). Bitcoin will create a "change" portion of the transaction where the remaining 11 BTC goes to address (C). Why not send ...
7
votes
2answers
4k views

How does the ECDSA verification algorithm work during transaction?

I understand the basic concept ECDSA where if Bob wants to sign a message it generates a random number n, multiply it with the secp256k1, r = the x value , s = (H(x)dr)*n^-1 mod q. Also the ...
36
votes
6answers
23k views

What happens if I mistype the address when making a payment?

I sent bitcoins to an address, but I think I made a typo when I copied it. Where did these bitcoins go. Can I get them back?
47
votes
2answers
36k views

What are bitcoin “confirmations”?

When I receive bitcoins I see a certain number of "confirmations" in the client. What do these mean? Why do most sites make me wait for 6 "confirmations" before a purchase will go through?
36
votes
5answers
2k views

How do I accept bitcoin payments at a real world store?

From what I understand, there are some requirements for using bitcoins at a physical store: Both the store owner and the client must have Internet access The client must have a cellphone or a laptop ...
41
votes
4answers
35k views

What are multi-signature transactions?

What are multi-signature transactions, and why might they be used? Also see: How does one make multisignature transactions with the bitcoin client? How can I create a multi signature 2-of-3 ...
17
votes
4answers
11k views

How can I create a multi signature 2-of-3 transaction?

Can somebody help me with step-by-step list of how to create a multi signature 2-of-3 transaction?
11
votes
1answer
3k views

UTXO model vs. account/balance model

I understand that Bitcoin uses unspent tx output and Ethereum account balance based. However, recently there are lots of discussions on that Bitcoin's UTXO database has become too big. Does this mean ...
43
votes
5answers
24k views

What is meant by Bitcoin dust?

I've seen the term "dust" used to describe small transactions that might be considered as spam by the Bitcoin network. Is there is a generally accepted definition of this term?
11
votes
2answers
4k views

How to sign a transaction with multiple inputs?

I have been able to program an application in python that sends valid transactions that spend 1 input, but I really can't get it to work with 2 or more inputs. So my question is, how exactly is the ...
39
votes
2answers
20k views

Explanation of what an OP_RETURN transaction looks like

How is OP_RETURN used and why was it introduced in the first place?
24
votes
3answers
34k views

What is a double spend?

What is a double spend? As someone who uses Bitcoin, what do I need to know about how the Bitcoin system prevents double spends? Are there still circumstances where they can occur?
15
votes
2answers
8k views

What is the maximum size of a transaction?

I see from the source code (script.cpp) that there is an upper limit in the script size. It there any other limit to avoid a single transaction preventing other transactions of smaller sizes to get ...
71
votes
6answers
18k views

How can I accept bitcoins on my website?

I have an online store and would like to begin accepting bitcoins. How can I go about doing this?
30
votes
2answers
12k views

What is a Finney attack?

What is a Finney attack? Extra points for explaining its purpose, the prerequisites for it to be possible, how the attack can be performed and the origin of the name "Finney attack".
13
votes
6answers
6k views

How to debug a long “0/unconfirmed” status in the bitcoin client?

When someone gets a status of "0/unconfirmed" on a transaction for a long time - what could he be doing wrong? What should he check to solve this?
4
votes
1answer
732 views

How is transaction fee calculated?

Some says that transaction fee is calculated based on the size of transactions. In short, does it mean based on the number of utxos? To be precise, does it mean depending on the size of all of input ...
27
votes
5answers
9k views

In getrawtransaction, what is the vout integer in the vin list?

I'm working on trawling the bitcoin transactions coming in via getrawtransaction. I haven't been able to find the neccessary documentation to describe the vout integer in the vin array: {"txid"=>"...
23
votes
1answer
4k views

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 ...
28
votes
5answers
2k views

What would happen if a portion of the Bitcoin network was separated from the rest of the network?

Yesterday I asked a question over at SuperUser, so that I could have my facts straight before asking this question. The scenario sets the basis for this question. Regarding bitcoin, what would ...
28
votes
2answers
20k views

Why are there two transaction outputs when sending to one address?

I did a small transaction some days ago: https://www.blockchain.com/btc/tx/4c07a07dfd9d5b79d168ec6835df876c64e82350a8f9211bf586d858a5aeb9ba Some info: 1JFWE8THcAQQRYx99c43DXSGyoPL9Zs62D is my ...
14
votes
7answers
4k views

Are bitcoins INHERENTLY fungible?

Does each bitcoin has a unique identifier, like currency notes have serial numbers? If so, could you trace a particular bitcoin's ownership chain (ie find the current owner of a particular bitcoin by ...
5
votes
3answers
1k views

How can I avoid paying transaction fees?

A bitcoin transaction requires paying a fee to the network, and that fee changes depending on network congestion. During busy times the fee rate may increase substantially, so how can a user avoid ...
39
votes
4answers
39k views

How do I see the IP address of a bitcoin transaction?

How do I see the IP address that someone used to send or receive bitcoins with? Is it stored in the blockchain?
21
votes
2answers
11k views

How to sign a transaction using only an offline computer?

I think it is possible to generate keys on an offline computer and sign. To create a transaction I need to input transactions detail, and somehow I have to transfer signed transaction from offline ...
13
votes
4answers
3k views

Can a Bitcoin transaction have the same address for input and output?

Can a Bitcoin transaction have the same address for input and output, i.e. spend some of the coins that are linked to an address and send the rest back to that same address? Is there some reason why ...
18
votes
3answers
1k views

Can a bitcoin transaction be reversed from the receiving end?

I know this seems like a duplicate of the question 'Can a bitcoin transaction be reversed?' but none of the answers there were explicit enough as they all seemed to assume reversal triggered from the ...
6
votes
1answer
2k views

Can multiple transactions transferring the same bitcoin be done in one block?

For example, one bitcoin from address A to address B, then from address B to address C, Assuming that prior to the transfer from address A to address B, no bitcoin had been sent to address B. If ...
14
votes
1answer
2k views

How to know there is a new transaction?

I am developing a program that monitors transactions. The first question is how can I know there is a new transaction? I can consider the command listtransactions. However, there is a bit of an issue ...
37
votes
2answers
32k views

Do unconfirmed transactions expire?

Do they just sit there unconfirmed (e.g. when you be evil and don't pay a tx fee) forever? Or do they get deleted after a few days?
28
votes
3answers
46k views

What's the minimum transaction with bitcoin?

What's the minimum transaction with bitcoin - local wallet to local wallet. Can I send for example $20 in bitcoins to another person?
46
votes
7answers
9k views

Is there any way to track an individual bitcoin (or satoshi)?

For example, if I wanted to "collect" important bitcoins is there any way to track a coin rather than a series of transactions? If I wanted one of the bitcoins from the infamous "Bitcoin pizza" ...
7
votes
3answers
4k views

What is a step by step way to insert data in OP_RETURN?

I was following https://bitcointalk.org/index.php?topic=453086.0 for creating a message in OP_RETURN. I am able to decode my raw transaction, but on signrawtransaction it gives error: {"code":-22,"...
15
votes
3answers
4k views

What is the number of transactions in a block?

What determines the number of transactions that can be validated in a block?
13
votes
3answers
7k views

What is the exact formula for calculating transaction fees?

According to the Wiki: If the blocksize is more than 250 kB, transactions get increasingly more expensive as the blocksize approaches the limit of 500 kB. Sending a transaction when the blocksize ...
11
votes
2answers
4k views

Transactions with a wait time (using nLockTime)

I'd like to know if there are transactions that can only take place at some predefined moment. In principle, it should be possible to use the parameter nLockTime to wait for a particular block number: ...
22
votes
2answers
2k views

What percentage of Bitcoin transactions never complete?

Occasionally transactions will be broadcast to the network that will show in a 0/unconfirmed status in the Bitcoin client. It is also the case that from time to time for various reasons those ...
5
votes
3answers
1k views

How can market-based transaction fees scale?

Can someone please explain to me what I am missing? I don't see how variable, market-based transaction fees can scale. I go to a merchant's website to buy, how do I select a mining peer to pay ...
15
votes
1answer
967 views

Are Bitcoin transactions permitted to have no outputs (i.e. all inputs become transaction fee)?

I am interested in the possible use of the Bitcoin (or other altcoin) blockchain as a generalized distributed ledger, meaning that it is useful for tracking information other than coin transactions ...
3
votes
1answer
1k views

What is a block?

I know bitcoin has a block chain that is from my best representation a list of blocks. I know the block holds many transactions. But i'm still very much lost as to what a block is and how a block can ...
8
votes
3answers
7k views

How to calculate a hash of a Tx?

How does one calculate the hash of a Tx? Which fields need to be double SHA hashed and in what order?
7
votes
2answers
2k views

Why does the blockchain need blocks?

I think I understand the main parts of the Bitcoin blockchain. While I was explaining the concept to my girlfriend she asked me why groups of transactions are actually stored in a block? Every ...