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.

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4
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1answer
1k views

How is the hash that is signed calculated?

I'm a bit confused about the signature contained in the scriptSig of a transaction. My question is: what do we really sign? Is it the hash of the previous transaction?
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339 views

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 ...
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3answers
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Is there an open source tool to publicly destroy bitcoins?

Several interesting applications of bitcoins involve a scenario where they are intentionally "destroyed". Is there an open source tool that can be used to destroy bitcoins? And if so, is it possible ...
4
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1answer
566 views

Does it make sense to “collect” smaller transactions balances into a single account during low activity?

My understanding is that it's possible for extra bitcoins to be left in several accounts within my wallet. The scattering of these coins into different accounts may cause future transactions to ...
4
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2answers
864 views

Invalid public key was spent! How was this possible?

From previous questions this bitcoin 1FYMZEHnszCHKTBdFZ2DLrUuk3dGwYKQxh address had an invalid public key of "00" and was unspendable but the coins are now spent?? The invalid key was generated by a ...
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1answer
2k views

How to access any transaction detail in Bitcoin version 0.8 and above?

Since the Standard Client version 0.8 removed the full index of all historical transactions, some Bitcoin applications that relied on that functionality have stopped working. For example, one is no ...
3
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1answer
520 views

How can there be multiple outputs with same address in the same transaction?

I received a transaction such as below: (I changed the actual numbers but the format is exactly the same) { "amount" : 0.3, "confirmations" : 739, "blockhash" : "...
3
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1answer
401 views

Can transaction inputs reference outputs of pending transactions?

The inputs of a transaction reference outputs of previous transactions. These previous transactions must already be present in the block chain, or can also be pending transactions? I don't know if ...
3
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2answers
2k views

How to get a history of incoming and outgoing transactions for a certain address?

Along with the history of incoming and outgoing transactions, how would I find the first block that that address appeared in (to find when the wallet was created)? I want to do this by parsing with ...
3
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5answers
938 views

How to stream transactions on the network

How would I go about getting a stream of transactions broadcast on the Bitcoin network? Is this supported by the vanilla client? I know that the client can notify me on new blocks and on all ...
2
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1answer
576 views

How to tell which part of the previous tx I need to make the hash to sign for an old given tx?

I have recently been taught (here) how to create the hash to sign for a given "input script" for an existing transaction. I then sought to test my abilities and sought out a difficult transaction to ...
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2answers
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How to create the <sig> <PubK> part in “scriptSig”?

I've decoderawtransaction and see in the vin part a "scriptSig" ,which I believe to be the "unlocking script" . Assuming I have the private key in a paper wallet and someone send me transaction to my ...
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5answers
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Is there a way to initiate a payment request in bitcoin?

I'm writing a recurring billing system and I want to be able to contact a customer and request a certain amount of money. Is this possible via bitcoin? If not, could a URL be provided the customer so ...
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3answers
989 views

Can the number of transactions per second ever overwhelm the network?

I'm coming at this from a point of view that assumes Bitcoin has been widely adopted as a currency worldwide and is essentially mainstream. Every day people are using Bitcoin in the same way that they ...
14
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3answers
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Eligius pool and 'generated' bitcoins

I mine at Eligius pool and sometimes a new transaction appears in my bitcoin client labeled 'Generated'. Why does this happen? Do I also get these 'Generated' bitcoins if I use an e-wallet's address ...
12
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1answer
2k views

Why do we need blockchains?

We can generate and verify transactions without blockchain - why do we need it? I can generate a transaction, broadcast it to the network, it can be verified multiple times etc.
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2answers
2k views

How many bitcoins have been sent to Base58-invalid addresses?

Some bitcoins have been permanently lost when they are sent the the following addresses. The explanation I've found is that they contain characters that are invalid in Base58 ...
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2answers
2k views

Where is the Signature stored in a SegWit transaction?

I understand that SegWit makes transaction blockdata smaller, by not storing the signature in the Block, so that can fit more transactions in 1MB. This is because the signature is not anymore stored ...
8
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1answer
1k views

Can a single transaction have multiple outputs going to the same address?

I understand that a transaction can have multiple outputs. But can two outputs in a transaction refer to the same target address? Here's how this would like in pseudo style: [vout] => Array ...
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3answers
3k views

How would you end up with more than two transaction outputs?

I saw a Bitcoin transaction that has 6 inputs and 4 outputs. I understand that several inputs are sometimes used in order to meet the amount requirements of the output. As a result you have two ...
7
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2answers
917 views

Can different clients have different transaction fees?

BitCoin Wiki states: Different bitcoin clients and different versions have different rules for determining which transactions to accept and how large a fee to send.. Is it true that different ...
6
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2answers
5k views

How to do mass payouts in my application to multiple addresses at once, or very quickly?

Let's say it's pay day--I've accumulated a lot of bitcoins, and sent them all to a single address. I now want to pay a lot of addresses from this "pool" of coins, say anywhere between 100 and 10,000 ...
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1answer
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If addresses are hashes of public keys, how are signatures verified?

I've skimmed through the https://en.bitcoin.it/wiki/Protocol_specification and it seems that when sending someone bitcoins, I would sign the transaction data (not quite sure which parts exactly) with ...
5
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2answers
688 views

Can an output be spent in the block in which it is contained?

Is a Bitcoin block containing both a transaction that funds an output, and another transaction that immediately spends the same output, allowed by the protocol? Does such behavior occur "in the wild",...
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3answers
833 views

What are the risks of in-person private currency exchanging for travellers?

This answer suggests popularity growth of people privately exchanging bitcoins for a physical currency, in person. This might occur in "coffee shops, hotels, hostels, hackerspaces, etc". An example ...
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3answers
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Starting point for listening to bitcoin network transactions in Python

I would like to create a python script that listens to the bitcoin network and monitors some addresses, stored in a mysql db. As soon as a transaction is broadcast with one of these addresses as an ...
4
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1answer
561 views

nLockTime transactions, how do they persist? Are they broadcast before they are valid?

If nLockTime transactions aren't added to the blockchain until the nLockTime is met, then aren't they just being stored in memory of the miners and is there a risk they could get "lost"? I guess I'm ...
4
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1answer
314 views

Is it possible to collect bitcoins? (as a collectors item)

Is there any analogy to collecting BitCoins as there is in the physical world? For example, some notriety was given to the Pizza for bitcoin transaction here, and one of the answers was able to ...
4
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1answer
220 views

Lightweight client, bare necessities

What are the bare data necessities that a lightweight client would have to get from a server client in order to perform basic wallet tasks (show balance, transaction history, number of confirmations, ...
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1answer
3k views

How is a transaction's output signed?

In a transaction Tx, the hash pointer of the earlier transaction (say TxE) that serves as input to Tx must be signed by the sender S of Tx. This is to show that S was the recipient of TxE. It remains ...
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2answers
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How to interact with bitcoind using C++?

I know that bitcoind is written in C++, but I cannot figure out how to use its API within my program. I have been using a Python wrapper effectively, but I need another process running that is as ...
3
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1answer
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Do all Tx's have UTXO?

I am trying to understand how UTXO works. I came up with these charts https://statoshi.info/dashboard/db/unspent-transaction-output-set I don't understand why the 1st chart (total Tx's with unspent ...
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5answers
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3
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1answer
4k views

How to get instant notification of any Bitcoin transaction involving a specific public address as recipient without knowing the wallet or private key

Everything is in the title... For instance, Blockchain can do this if you import a public address and you set up their notification mechanism. Is there a way to do this in an intelligent (=efficient) ...
3
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1answer
938 views

Missing public key in transaction input

I'm in the process of understanding scriptSigs of transaction inputs and encountered some transactions with inputs that seem to be missing a public key. This is what I expect to see as a scriptSig. A ...
3
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1answer
386 views

How should a Bitcoin Oracle verify a transaction prior to signing?

What are the specific parts of a transaction(s) that need to be signed in the "inheritance scripting sample". Specifically, can someone provide more detail on what exactly is signed of the ...
3
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1answer
176 views

Why Bitcoin uses UTXO model? [duplicate]

I know what it means. But I can't understand why Bitcoin decided to make such a model, where you have no balance, only unspent transaction outputs. And isn't the same thing as having the balance? I ...
3
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2answers
753 views

Does sending non-ripple-money through Ripple require two people to be connected through a web of trust?

Say we have two people - first one puts some money into their Ripple address through a use of a gateway. They are not trusting anyone on the network, but need to send their money to a second party ...
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4answers
2k views

How does a wallet use unconfirmed outputs as inputs after unconfirmed transactions?

I have 10 btc on address A. Using raw transaction, I send 5btc from A to B and set the change address as A itself. Now because the transaction from A to B is not confirmed I can't spend the remaining ...
3
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1answer
613 views

Creating secure architecture and payout process

I studied lots of valuable q&a here, but still I have some doubts. Case - simple game (calm down - I'm not one of the rookies creating exchange as seen here), which allows to pay for a game. The ...
3
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2answers
2k views

How do I get to the value in the 'scriptPubKey' part of the transaction ?

How do I get to the value in the 'scriptPubKey' part of the transaction ? The sender knows only the address (1A3XjcuZmcszX2tGoVn1TrMNchuHwdAxZV) so how did he get into ...
3
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1answer
778 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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2answers
236 views

Single tx included in two different blocks

https://www.blockchain.com/btc/tx/a7bacce00e5df85d3547a3f83ac10c65eec30f715c1d77d8d4a7bc17fd470965 How is it possible that a single tx is included in two different blocks? Isn't it considered double ...
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1answer
4k views

What does a Bitcoin transaction consist of?

I gather that 2400 transactions fit into a 1 MB block. That's 436 bytes per transaction record. But what's in a transaction record? Is there a good Powerpoint presentation that describes how Bitcoin ...
3
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1answer
620 views

BIP65: “replacing ntimelock entirely”?

BIP65 discusses replacing the ntimelock field with the new CHECKLOCKTIMEVERIFY OP code: As an aside, note how if the SignatureHash() algorithm could optionally cover part of the scriptSig the ...
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2answers
1k views

Is there a standard procedure for refunding Bitcoin transactions?

I work for an online retailer, and we're currently testing a Coinbase payment implementation for our checkout. One of our big concerns is being able to send a refund in the event that we're unable to ...
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2answers
1k views

Multisig vs Multi input transaction signing

Let's say we have a 2 of 2 multisig address that we want to spend from, so the transaction should be signed by both of the private keys. Now let's say we have a transaction with two inputs, so once ...
2
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1answer
782 views

Reading transactions from blk*.dat files

I'm reading through each blk*.dat file in order. As I'm reading through each transaction, is it possible that I will read a transaction that is referencing an output (as an input) that I haven't ...
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2answers
111 views

Are Bitcoin signatures currency specific?

I am wondering whether signatures for Bitcoin-like currencies are currency specific, or given one program that can sign a Bitcoin raw/JSON transaction one can create valid signatures for other coins ...
2
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1answer
7k views

Bitcoin sent to a defunct address - what happens to it?

I got the address for my account on a site and wrote it down. As I had had a huge hassle buying my bitcoin that morning due to problems with the vendor's site (and which they denied was at their end ...