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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How bitcoin nodes update UTXO set when their latests blocks are replaced?

Let's say bitcoin node has 100 blocks. Then he recieve another two blocks. Now it have 102 blocks. But now he recieve block 103. And this block is from another chain and our node have to remove blocks ...
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1answer
119 views

Do transactions with old UTXOs take longer to confirm?

Suppose I do a transaction with an UXTO created years ago. Would that take longer to confirm because miners would have to look further back in the transaction chain to verify it?
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Why do we need CCoins in addition to CTransactions?

As per my understanding CTransactions represents the atomic unit in Bitcoin. It has the inputs CTxIn and outputs CTxOut. Can any expert give the intuition of why we need CCoins in source code ? Why ...
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How does the wallet identify which UTXOs belong to a public address while creating a new transaction?

I am a beginner here. A Transaction output has a field for amount and a locking script but no direct field for public address for which the output is meant. When a new transaction is being created, ...
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1answer
303 views

Why does the order in which the transactions occur matter when we reconstruct ownership information?

I was wondering why the order in which the transactions occur matters when we reconstruct ownership information. Can't we just aggregate all the input and output for each account to calculate how much ...
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1answer
2k views

How is the UTXO database initialized?

The IDs of the unspent transactions are stored in the UTXO database. I assume that it's generated like this by the client: for block in blocks: for transaction in block: utxo.remove(...
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1answer
83 views

what is meant by DEFAULT_ANCESTOR_LIMIT in child pay for parent?

Why is 25 the max parents a child can rescue in a child pay for parent? I don't think I understand what DEFAULT_ANCESTOR_LIMIT = 25 means. Does that also mean that the child transaction has 25 ...
3
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1answer
106 views

Fundamentals: Addresses don't hold coins, wallets do?

In the beginning it was my understanding that: Every address has a private key Every address has a balance Every address may send and receive coins. This is simple. But now I am using more proper ...
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2answers
562 views

CVarint serialization format

Recently I started analyzing the UTXO set data that every full node stores in chainstate folder (a LevelDB database). By looking into the code you can learn more or less how the data entries are ...
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268 views

What's the maximum possible utxo growth rate now? Can that be turned into an attack?

Now bitcoin unspent transaction output growth rate (not total size) can be, 260k utxo/day (3×60×60×24). With 8MB blocks, that's 2.8 million. Single 1 bitcoin output can be split into 1000 x 1 mBTC ...
3
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1answer
96 views

Do you 'own' Bitcoins purchased via an exchange?

I have been told by some that bitcoin exchanges do NOT record BTC transactions by a buyer/seller on the blockchain, but rather hold them in their own name and ledger - eg, if I buy one BTC via an ...
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1answer
382 views

Extracting information from utxo for offline processing

I would like to extract as much information about the utxo set (all unspent transactions) up to a given block height, including value and scriptpubkey. This information is meant to be inserted into ...
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Why do we refer to previous transactions in each transaction?

Isn't it enough to just have the Input Address, Output Address, Amount and Signature for each transaction?
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888 views

How to directly query leveldb database to get get a record by transaction hash or by sender's address?

I learned that the blocks and transactions are stored locally in .bitcoin/blocks/index and .bitcoin/chainstate databases, respectively. I want to make a direct query to those databases to measure the ...
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3answers
549 views

How long is a Bitcoin?

I searched already but I couldn't find anything about the structure of a bitcoin. My understanding is that a bitcoin, which is different AFAIK from a bitcoin address, can be interpreted as a string ...
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2answers
7k views

How can the transaction history be checked when new addresses are generated?

When a new transaction is executed via a Bitcoin-client, the sender will have a different address than the ones used in previous transactions. I also know that all the full nodes in the Bitcoin ...
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1answer
446 views

utxo vs account-model [duplicate]

There are two possible models, the UTXO model and the account model. Each has advantages and disadvantages. Bitcoin chose the UTXO model. XRP and Ethereum for example use an account model. What are ...
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4answers
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Why do some transactions have more than one input?

I know a normal transaction has 1 input and 2 outputs (if there is change that is the second output). But what about this scenario? Lets say I'm withdrawing bitcoin from my gemini account and want ...
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2answers
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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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Other database besides UTXO?

In this post it is explained that the UTXO are removed after they are spent. This makes sense because they are not "unspent" anymore. But don't all UTXOs have a reference/connection to their ...
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2answers
226 views

If I reuse the same address can a previously used transaction be reused?

I was wondering, if I used an address adr0 to spend some coins in a transaction tx0 that give the coins to a different address adr1, and eventually, after some time, I receive some (completely ...
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1answer
618 views

How does one reference an unspent transaction output?

In a bitcoin transaction the previous unspent transaction outputs are referenced. How are these referenced? Do outputs have unique reference or maybe as unique transaction reference X output ...
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2answers
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Multiple Addresses in one UTXO

The 'decoderawtransaction' RPC method of the Bitcoin-QT client gives a JSON object with an array of addresses in each UTXO. For example, when I run: decoderawtransaction "...
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2answers
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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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2answers
690 views

fetching unconfirmed utxos from blockchain.info

A few weeks ago, I would retrieve unconfirmed utxos from Blockchain.info doing API call https://blockchain.info/unspent?active=$address. That enabled me to successfully make a micropayment channel (...
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Can the coinbase transaction be used to spend an UTXO?

I know the coinbase transaction's input is usually just has a dummy scriptSig, but what if a miner used it to spend an UTXO? Would it be verified as an actual spend, or would the block be rejected?
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How to prevent double spending Bitcoins?

If I create a transaction, my node will check my UTXO's and if i have enough BTC to do this transaction it will be mined. So let's say I want to spend 12 BTC to Anna. The System will check if i ...
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1answer
473 views

State of transaction and UTXO

What I have learned is that state is an abstract thing and is maintained by the node locally and the state of the current blockchain can be reached by starting all the way from the genesis block and ...
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1answer
819 views

Parse UTXO of a transaction from chainstate

I'm doing some analysis on the UTXO set by reading from the chainstate database. I was following the documents given by https://github.com/bitcoin/bitcoin/blob/...
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2answers
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How to Get UTXO using bitcore-lib?

I am using this library to make a wallet service that runs on a web browser. I use the library and browserify it so its compatible with the rest of my jquery. Now this tells me how to make and sign a ...
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1answer
273 views

Why is utxo time a priority for miners?

I've understood (maybe mistakenly) that once free transactions arrived to be collected into new block the miner will prioritize them by fee, then by maturity, meaning will take the transaction with ...
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1answer
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What is the link between address and use of the UTXO?

I state that I'm still a beginner. I need some clarification. I am using the Testnet. This is the information regarding the address I used to receive funds from a Faucet bitcoin-cli validateaddress ...
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1answer
96 views

How to query all utxos of an address from a full node?

I am new in the blockchain field, and I am trying to build my own block explorer from scratch to really learn about Bitcoin. I am currently running a full node in a raspberry pi, and I have already ...
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1answer
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How do blockchains in each nodes maintain consistency?

What I understand as (Please correct me if any statement is wrong) Every full node tries to generate a new block, in which different amount of transactions are included and what to be included will ...
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3answers
1k views

Litecoin litecore-lib receive UTXO and current balance

I have coded NodeJS script for bitcoin for send all balance from by address to some other one. Now I want to do this for the litecoin. For bitcoin I have used bitcore-lib and bitcore-explorers libs to ...
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1answer
171 views

Why does unspent address index differ between APIs?

I've been using Blocktrail's API: https://www.blocktrail.com/api/docs/lang/nodejs#data_overview to get data for the following unspent address on the testnet: 2N6qMqR9D4BTkD6fS1h6Sq3kRV2FeB1L14j. ...
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1answer
144 views

Is reliance on a UTXO Set provided by other users dangerous?

One of the largest hurdles in my mind to increasing the number of full nodes operating is the startup cost related to downloading the blockchain. A similar but less important (in my mind) issue is ...
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1answer
273 views

Where can I see the code of how the UTXO set is updated in case of a fork in Bitcoin Core?

I am looking for a filename and a line, or multiple ones if necessary. My goal is to maintain an index of addresses to UTXOs.
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1answer
187 views

What are spent transactions?

Satoshi's paper says: Once the latest transaction in a coin is buried under enough blocks, the spent transactions before it can be discarded to save disk space. What are spent transactions?
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1answer
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How does serializing in coins.h work?

I'm talking specifically about this: /** pruned version of CTransaction: only retains metadata and unspent transaction outputs * * Serialized format: * - VARINT(nVersion) * - VARINT(nCode) * - ...
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1answer
170 views

What happens to a node if .bitcoin/chainstate is corrupted?

I tried to search for answers to my questions, but didn't find any, but please forgive me if this is a duplicate question. Suppose somehow .bitcoin/chainstate gets corrupted, e.g., a UTXO is deleted. ...
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1answer
2k views

How can you consolidate your personal UTXO set? (different wallet answers welcomed)

With network fees so low at the moment, I've seen a lot of recommendations to take the opportunity to move funds to segwit addresses and consolidate your UTXO set. During peak congestion, many smaller ...
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1answer
106 views

How to distribute UTXOs in hard fork while preserving privacy?

Let us say I have a UTXO set S = {U1,U2, U3 ..., Uk} on a pre-fork bitcoin blockchain. How do I spend the previous UTXO S so that the new UTXO sets on both the chains are not linkable/tracable? Are ...
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3answers
960 views

What is the best way to download a “recent” UTXO set snapshot?

I am using bitcoinj to listen for payments. I need a way to maintain the entire UTXO set in a local database. Can bitcoinj be used to download every block (I think it downloads only recent blocks ...
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1answer
620 views

How to work out the balance for an HD Wallet extended private key?

I am working in C# with NBitcoin. I have created an extended master private key, and I can create the hierarchy of derived keys. In TestNet, I have requested some coin from a faucet, and the ...
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1answer
887 views

How do you create a transaction from a UTXO in BitcoinJ?

Is there a way to construct and send a transaction in BitcoinJ without a wallet? I just want to build my transaction from a utxo and broadcast it.
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2answers
1k views

Is there any tool to index ALL bitcoind UTXO?

I've got a full bitcoind node with txindex=1. listunspent command is useful only if node is in possession of a private key for address. So, if I want to check UTXO for random address, it will not ...
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1answer
384 views

How is UTXO tracked?

What is the best way to compute UTXO of any address? Do I have to traverse whole block chain each time? Is there a efficient way to compute it?
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2answers
727 views

How can this input address have multiple values at the same time?

For the transaction: https://blockchain.info/tx/ee1658bb4d0de80a91d2e0005218d4cfab7c302a352458bd6afb6376b47fbf81 it looks like there are multiple inputs with different values for the same address. I ...
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Is there a UTXO for IOTA? [closed]

How does the cryptocurrency IOTA keep record of the spent coins? Is there something similar to the UTXO where the unspent coins were recorded? And it somebody wants to spend a coin, do you have to ...