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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416 views

how can i query utxo to bitcoind(using bitcoin-cli) with public-private key not wallet

i want make a transaction to send bitcoin to others. so i need utxo by someones' adfress. but bitcoin-cli listunspent command only allows address in wallet. is it any idea to query listunspent with ...
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How to find utxo?

I might be over thinking this, but I'm trying to figure out the best way to build an unspent output pool. Should I just naively parse every block? Every input gets removed from the hash set, and every ...
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How is a Transaction Output Marked as Spent?

The Bitcoin developer guide states that each output of a particular transaction can only be used as an input once in the block chain. Any subsequent reference is a forbidden double spend—an ...
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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
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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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2answers
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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
164 views

Double spending UTXOs

I know that the inputs for a transaction(which is not coinbase) are UTXOs. Are UTXOs kept track of by some servers and also the owner's wallet? If there are servers which keep track of UTXOs, is it ...
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what's CCoinsViewDB::GetHeadBlocks for?

I have google a lot, there exists little information, confused with the code comments Retrieve the range of blocks that may have been only partially written. If the database is in a consistent state,...
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1answer
3k views

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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1answer
69 views

What are the mechanics of verifying that an output transaction is not spent?

I am trying to understand the mechanics of how a bitcoin transaction works. When the output gets consumed by a later transaction, who and how prevents this output from being consumed a second time? Do ...
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BTC not received after sending

I have a transaction sent from Coinbase on 12 Dec 2017. i can see it on the blockchain, fees taken but the rest is unspent. How can I force the transaction to complete. Why didn't it complete ...
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1answer
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Will all UTXOs eventually be worth 1 Satoshi?

If I want to spend 0.4BTC and I only have a UTXO for 1.0BTC, I will send 0.4BTC to the seller's address and 0.6BTC to my address. The seller has one UTXO and I have the other. One UTXO has become two....
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1answer
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What is the Big-O complexity to retrieve the balance for a user?

Here is the Q/A related to: How is a wallet's balance computed?. Based on this: [Q] What is the Big-O complexity to retrieve the balance for a user? Is it O(n), so basically do I have to iterate ...
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When you receive a BitCoin what do you actually get?

Say someone sends me 0.5 of a BTC to my desktop wallet, is it a digital file or lines of code that they send me which has monetary value? I'm very confused on what you actually RECEIVE with ...
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2answers
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Why the “Unspent Transaction Output Set” is called “UTXO”, not “UTOS”?

Just out of curiosity, the Wiki says UTXO means "Unspent Transaction Output", but what does each letter mean in the acronym?
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Where to find UTXO Metadata API

I'm looking for an API which lets me query for UTXOs on the base of specific meta data, e.g: When was the transaction containing the UTXO issued? From which address? etc. I have found this question: ...
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How is a wallet's balance computed?

I am wondering on how a wallet's balance is computed. Basically, from what I've read I assume that you look back at all transactions involving all the keypairs of a given wallet. Adding up all the ...
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634 views

Getting a crypto proof UTXO set

How to get a list of unspent transactions outputs (UTXO) from local files? Where is stored this data? In what files this data is fully present? I understand that this list is in "chainstate". But ...
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1answer
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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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2k views

How to check if an output has been spent?

Using an rpc client (e.g. bitcoin-cli), for a given transaction and index of an output of it, how can I tell if the output is currently an utxo, or if it has already been spent? In the latter case, I'...
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1answer
588 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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What is crypto-proof UTXO set?

There are many opinions about getting the actual UTXO set of blockchain. Do you think that this important database must be based on data which saved on disk and never modified after, only appended? ...
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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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With 100% segwit transactions, what would be the max number of transaction confirmation possible on a block?

With 100% segwit transactions, what would be the max number of transaction confirmation possible on a block? And, how many utxo can be updated by a block full of segwit transactions?
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What is an “unspent output”?

What is the meaning of the term "unspent output" in the Bitcoin protocol?
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1answer
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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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How big is the UTXO database?

Is there a query that will return the size of the UTXO database? Specifically, the total number of unspent outputs.
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Can there be a half segwit, half normal Bitcoin transaction?

I was wondering if it's feasible to compile a bitcoin transaction that is somewhere in between (segwit and non-segwit), maybe one of these scenarios. I'll call the non-segwit inputs, normal inputs ...
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1answer
215 views

How does Bitcoin protect against doublespends?

I am trying to understand the blockchain and I have read a bunch of these explanations, but they all don't address some of the questions I am still wondering about. So first I'll explain what I know, ...
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Why has UTXO set stopped growing since 2017-06-03?

The bitcoin UTXO set appears to have stopped growing on 2017-06-3 after 5 or more years of nearly constant increase. What are the reasons (or hypotheses) why? Charts below: 2012 to 2017-07-11 https:/...
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1answer
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How to create a tx that cannot be replayed?

I've got a very precise question about (self-)protection vs replay attacks in Bitcoin but to clearly explain myself, I need to explain what I did with Ethereum. When the Ethereum fork happened (ETH /...
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Where does Trezor get UTXOs from?

Since UTXOs are required to spend funds, where does Trezor get the unspent outputs from? Storing them in the hardware requires you to plug it in from time to time to update the UTXO set. You could ...
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How many UTXOs have a marginal fee cost that's higher than its worth?

I define marginal fee cost as the number of bytes required to add that UTXO as an input to a TX multiplied by the satoshi/byte rate of the blocks being found. So for a normal p2pkh UTXO, this would ...
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How many unspent transaction outputs are there?

I was wondering the other day how many unspent transaction outputs there are ? If you just keep track of the unspent transaction outputs you could import private keys, know its balance and perform ...
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1answer
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Where can I query the UTXO database?

Currently there are 35 million unspent transaction outputs. Is there a site somewhere where I can query this data to see, for instance, how many UTXO's exist with a value less than 20,000 satoshis? Or ...
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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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Where are my bitcoins - unconfirmed transactions [duplicate]

Using Bitcoin Core wallet, I sent coins to an address of mine outside of the wallet. All three transactions sit as unconfirmed though show in blockchain. https://blockchain.info/address/...
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1answer
761 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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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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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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Are the outputs of an unconfirmed transaction part of the global UTXO pool?

Well basically that. If a transaction is in the memory pool, that is, it is not yet in a block but nodes and miners know about it and validated it, Can I send another transaction that double-spends ...
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How is it possible to say that a bitcoin was fully spent?

Is a simple question, but I want to understand this at the low level. Since the UTXO is a database with the yet-to-be-spent coins, how can I say that a given coin was already full spent? What would ...
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2answers
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How does a miner know if a transaction has already been included in the block chain? Does he traverse through the complete chain to conclude this?

I am confused on what incentive a miner has on including a transaction apart from the transaction fee. So, if adding a transaction wastes any time, any miner should ideally not add transactions that ...
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1answer
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How can a Bitcoin transaction be used multiple times (If it is so)?

My understanding is that a transaction is a transfer of value between Bitcoin wallets that gets later included in the block chain. So a Bitcoin transaction is used only once in my understanding.
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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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1answer
360 views

How to get asm and hex from vout

I've got this weird string for a utx message (not my code) CTransaction(nVersion=1 vin=[CTxIn(prevout=COutPoint(hash=41caa5bf2b814135257b26e44b111f55c067f783e3cdf9bdf914e1ef7e403d05 n=0) scriptSig=...
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get utx scriptPubKey to become an object

I'm using this python script https://github.com/sebicas/bitcoin-sniffer When I see a utx I look at each output and find the scriptPubKey I expected to see something like "scriptPubKey": { "asm": ...
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1answer
571 views

Why do transactions send coins to the same address as they spent it from?

I often notice transactions such as: 364efe5a906de5971e242f9711008e58a5ab79f136a8044b66615e8662d35f09 Where funds from the address 3PU with 1.38 BTC are split to itself (1.35 BTC) and 37Ek (0....
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1answer
116 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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Where is the UTXO data stored?

When a new transaction is received it is added to the memory pool (after checking for conflicts). While mining, only the transactions which are in the pool are considered. What happens to the ...