Questions tagged [utxo]

Unspent Transaction Outputs (UTXOs) are created by transactions and allow the owner of an associated address to spend a specific amount.

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Send transaction with 2 inputs and 2 outputs using Blockcypher

I'm using a node.js client of Blockcypher in order to broadcast a Bitcoin transaction. My code: const originWalletBalance = getBalance(originAddress) const fee = calculateFee() const txBody = { ...
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Is the paying of a transaction fee have anything to do with UTXO?

Say I have two addresses in my bitcoin core wallet, address A contains 0.1 BTC and address B contains 0.15 I choose to transfer someone 0.1 BTC, but there is also some fee, say 0.00001. Will the ...
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Bitcoin UTXO Balance Checking

I think I understand how the UTXO model works, the inputs, and outputs, etc. However, one thing I am still having a hard time still, is understanding how balance is calculated from a seed or xkeys. If ...
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How many useable UTXOs are possible with BTC inside them?

I've heard there are somewhere in the range of 80-100 million possible UTXOs, where users could hold their own keys, with their BTC savings inside, and still have them spendable in the future. Best ...
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How do exchanges like binance or kucoin store user assets?

My questions about storing user assets: An exchange creates unique deposit addresses for each users. Are these addresses all derived from a HD wallet and exchange controls all the keys and indexes? ...
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What happens if a transaction is duplicated across different blocks?

I'm sure I am missing something trivial here but I have a question. Let's say there are Node A and Node B. We send a transaction to both nodes. Both nodes now contain an unconfirmed transaction in ...
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How is an unspent TX output value verified?

I know that the current UTXO set is the set of all unspent transaction outputs in the blockchain that is equal to the total number of all bitcoins mined currently and that each UTXO has a reference to ...
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How are Satoshis accounted for?

How are Satoshis accounted for and transferred? As in, is it the case that when I have ownership of a particular Sat at an address, is it actually that I own sat number 241536 from BitCoin number ...
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Did Satoshi invent UTXOs?

Did Satoshi invent the UTXO model (the concept of "unspent transaction outputs" that are spent fully when invoked, leaving new UTXOs and "change"), or was the UTXO model based on ...
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What exactly is signed in "prev_out"?

What is signed by scriptSig? I use my private key to sign data from the unspent transaction? I sign the "prev_out" object? I read that the signature in "prev_out" is there to ...
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Possible for 2 transactions from the same address within the same block?

I am not talking about double spend. I am referring to 2 diff txns For example, Alice has 10 btc. She sends 3 btc to Bob and 4 to Tom. Is that possible in the same block if she has 2 UTXOs with each ...
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Had a question on using on-Chain Data(Glassnode) to measure Unrealised/Realised profit and loss of BTC holders - isn't on-chain data not complete?

https://twitter.com/Negentropic_/status/1408436526262988801 The link above shows this tweet and pic: Isn't on-chain data not the full universe of transactions? for eg. Example 1: we have 10 users ...
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Are a new set of keys created for each UTXO, or can multiple UTXOs be locked by the same PubKey?

I understand that each transaction, new pairs of keys are generated, usually derived from a master key say in an HD wallet. If your change for a transaction or received BTC Is in multiple UTXOs, are ...
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Cannot unserialize chainstate transaction outputs after de-obfuscation

I was able to read chainstate database. Getting the key and de-obfuscating to get a valid last block. However, when it comes to transactions that follow after that, I cannot de-serialize them no ...
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Use wallet db for locked UTXOs in Bitcoin Core

Related question: Why are UTXO locks stored in memory only? Sorry this maybe a dumb question for people good with using database in C++ however I am not able to understand what exactly is going wrong ...
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Why are UTXO locks stored in memory only?

Locks are stored in memory only. Nodes start with zero locked outputs, and the locked output list is always cleared (by virtue of process exit) when a node stops or fails. https://bitcoincore.org/en/...
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Is it possible to assign a single "from" and a single "to" address to Bitcoin transactions?

I am working on a project where we need to get the "from" and "to" address for every transaction across a number of cryptocurrencies. In account-based currencies, this is pretty ...
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Are UTXOs signed with a private key?

Are UTXOs signed by a private key? I'm trying to understand exactly which parts of Bitcoin use public and private keys. You need a private key in order to generate transaction output, and to create a ...
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TX Validation: Can a miner choose specific tx to validate from mempool? [duplicate]

I have made two TXs few days back and they remain unconfirmed so far. Can I be a bitcoin miner and validate them myself? And what happens if it remains as it is? There are some big amount of utxo ...
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UTXO Model and Trans Fee / Kb Clarification

I have been working on understanding the inputs/outputs and transaction details as according to the UTXO model which is discussed in this question and also thinking about how it relates to transaction ...
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Confused about UTXO management and consolidation

I have a few questions regarding utxo management and consolidation. I know that the more UTXO's you have, the heavier your transaction will be, the more fees you'll have to pay. The things I don't ...
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How do I view the list of all existing Unspent Transaction Outputs, not just for my wallet, with Bitcoin Core utilities or any other software? [duplicate]

I'm preparing data for a research/analysis, and I'm a bit new to bitcoin-cli. I need to obtain data for the chart like this: https://www.blockchain.com/charts/utxo-count , with only difference that it ...
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How does a miner verify a transaction which is spending an output of another transaction in the same block?

It is mentioned in this post that: If all validation of all transactions in a block succeeds, the consumed inputs are removed from the database, and all outputs of those transactions added as fresh ...
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Are unspent UTXO's on Bitcoin from before the AUG 2017 BCH fork at risk to a replay attack?

Is it true that any UTXO's that are unspent prefork of BCH AUG 2017, has a risk of a replay attack? Say I have 1 BTC in my wallet which has never moved since 2016. Now I load that private key into BCH ...
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What were some discussed and current potential issues with pre-forked Bitcoin coins from August 2017 that have never moved since then?

I was speaking to a friend that mentioned that there were issues with pre-forked Bitcoin coins from Aug 2017 that never moved. He wouldn't tell me exactly what the potential issue was, but what were ...
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How does a full-node index watch-only addresses?

I can import watch-only addresses into my full-node's wallet. I can start querying their utxos from that point onward. Where are watch-only addresses stored and how does my node keep index of their ...
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Comparing UTXO transactions with Accounts transactions

I have seen few websites that compare number of transactions and fees between Bitcoin and Ethereum. Examples: https://www.flippening.watch/ and https://cryptofees.info/ What does the high number of ...
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What exactly is the "vout" field?

This is driving me nuts. Through trial-and-error, asking numerous people and attempting to read endless articles and manuals, I've come to the conclusion that the "transactions" listed by ...
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When the UTXO in the cache is full, what strategy is used to replace one UTXO with another in the cache?

The UTXO set is stored on the disk, but some UTXOs are also stored in the cache. When validating a transaction, you need to query the UTXO pointed to by the input of the transaction. First, you go to ...
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Signing transaction for later use

If I have a segwit UTXO with for example 10 BTC , can I make some raw transactions ready to get broadcasted?
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What does the index of an UTXO stand for?

For example, here is the output of an API I hit with one of my testnet UTXOs. What is the meaning of the index field in this context ? "utxo":[ { "block_id":1899516, ...
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How is the balance of a Bitcoin address quickly calculated?

For what I understand, the balance of a Bitcoin address is the total sum of UTXOs of that address in the entire blockchain. The current size of the blockchain is around 350GB. How is the total sum of ...
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How to approach building a custom UTXO index on top of a full-node

I want to avoid physically importing addresses into a wallet. I want to write a UTXO indexing system on a per-address basis. I often wonder how a wallet can keep track of all of its addresses UTXOs, ...
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571 views

When does Bitcoin update the UTXO set?

I am kind of confused with something. I hope you can clarify it for me... Let's say I want to make a transaction. So my exchange wallet does that for me. The way it does this is it first grabs the ...
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Practical tips for validating raw transactions

I have a protocol that creates a raw signed transaction that is then broadcast to the network. The transaction aims to send X BTC to a single address Z. The transaction is created with the help of ...
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Difference between crypto coin vs crypto block?

I have several doubts about cryptocurrency when I started(bitcoin) reading about it. I google it around and it only added to more confusion. I am not able to understand the difference between a ...
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I somehow sent a transaction to my own wallet address

I wanted to make a transaction to a vendor but somehow I made it to my own address? It is yellow color and I put very very low fee. It is unconfirmed yet because of the fees. Should I just increase ...
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How would you create child pay for parent in bitcoind-cli

I have unconfirmed transactions in my bitcoind wallet. Some of the are mine and some are incoming third party transactions. I want to speed up their confirmation by creating CHPFP transaction - ...
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How to use UTXO of xpub derived addresses?

I'm new in Bitcoin, this is something I'm confused with. If we are deriving children, i.e. public keys, from xpub, without private keys, for the purpose of receiving outputs, how are we able to spend ...
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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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how does node create UTXO from blockchain for the first time?

Let's say I am a new node. I try to synch with the full node to grab the whole blockchain. Now, I synced with it .It's time for my node to create UTXO database .. How does it do this exactly so that ...
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How is the UTXOs of each partially-spent TxIn determined?

My current understanding of a transaction is as follows: a transaction (Tx) can have multiple inputs (which are previous unspent transactions = UTXOs), let's call them the TxIn a Tx can have multiple ...
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How to Create or Generate a New UTXO in Bitcoin Core?

I know how to use Console in Bitcoin Core but not that expert. I would like to ask is there possible for me to generate or create a new UTXO in Bitcoin Core? All I have with me are the list of TxID ...
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Best way to find list of UTXO related to xpub

Apparently the way to find a list of UTXO related to an xpub is to derive all addresses from the master private key and query a node with each and every one of them. It is possible to generate ...
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How to create a transaction input from tx id of UTXO?

I'm in the midst of working this github --> https://github.com/karask/python-bitcoin-utils/blob/master/examples/spend_p2sh_transaction.py Sorry as I'm not that good in this. I would like to ask the ...
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Private Key leakage due to reusing same address, how to prevent?

1 What precisely is the meaning of "reusing"? Is it receiving multiple times coins to the same btc address? Or is it also about sending coins? 2 How can people avoid this leaking of ...
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Do you sign only the previous output of transaction?

I need to confirm that I understand how transactions work in the Bitcoin network. Ok, so: Alice is a network node. Alice wants to send bitcoins to someone in the network. Alice is creating a ...
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How do Bitcoin balances work when an address is controlled by multiple parties together?

user1, pubkey1, 1.1 BTC user2, pubkey2, 1.2 BTC user3, pubkey3, 1.3 BTC user4, pubkey4, 1.4 BTC user4 sends 0.4 BTC to a 2-of-3 multi-sig account controlled by user1, user2 and user3 using P2SH. The ...
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Why is there "Change" in Bitcoins?

I have read about a change address and wondered why there even is the concept of change? Let's say I received 1 BTC from some person A and I want to send 0.4 BTC to another person B, afterwards. From ...
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Can we determine which one of the referenced outputs corresponds to a cashback transaction in BTC transaction scripts?

let me quickly elaborate the question. The structure of a BTC transaction script looks somewhat like the following example "...

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