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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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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How to get unspent bitcoins using bitcoinj

I'm trying to get unspent transaction using bitcoinj like here without using api calls. How can I do this?
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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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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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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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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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5answers
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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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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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3answers
784 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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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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1answer
752 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
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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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Create an issuance and a send within the same block (XCP)

Using counterparty api I am issuing an asset, signing the raw transaction and sending raw transaction. Api I used is http://counterparty.io/docs/api/#create_issuance As it takes 10 or more minutes to ...
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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
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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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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 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 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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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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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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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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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
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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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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 ...
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1answer
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UTXO all sent to change address?

I have read this question that asks if all UTXOs in an address are sent to a change address or only the UTXO involved in the transaction. As part of a spending transaction, the public address is ...
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445 views

Is the UTXO set computed from scratch by new full nodes?

When a new full node joins the network, does he, by default, compute the UTXO set from scratch from the blockchain so far; or does he simply trust the UTXO set he received is valid?
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Why is Bitcoin Core using LevelDB instead of Redis or SQLite?

Why did Core move from BDB to LevelDB? Why don't they use SQLite or move to Redis now? Is there a technical reason for this choice?
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Bug with bitcoinchain.com? [closed]

The bug is with https://bitcoinchain.com Before I report it I would like to see if I can gain any additional clues as to what might be going on in order to assist their developers to get to the root ...
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Do all outputs have an address associated with them?

I guess more specifically, a decodable address? I have seen transactions on blockchain.info where the address was "unable to decode" Is there a way to count these? Also do they stay in the UTXO set ...
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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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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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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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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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258 views

Why is it not possible to replay transactions?

What if a miner takes a transaction which is already on the chain and adds it to a new block to earn the fee once more? Which mechanism prohibits replay attacks of this type?
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How can I extract the values of all UTXO for a specific section of the blockchain?

I'm working on some statistics concerning the distribution of the UTXO set. I'm especially interested in the values of the UTXO, and would perhaps like to limit extraction to certain sections of the ...
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Specification of Transaction Inputs - Bitcoin vs Ripple

In Bitcoin, the transaction inputs (UTXOs) are specified as a tuple (transaction index, vout) since there is no notion of an account in the bitcoin system and the address (pointed to by vout) alone ...
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Transaction with Multiple Inputs having Same Address

Why do transactions have multiple inputs with the same address? Is it because the amounts were obtained in the address through multiple separate transactions. Shouldn't the amounts be clubbed to a ...
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1answer
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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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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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How can a lightweight client make sure output has not been spent yet?

It's simple to prove the creation of a UTXO: You just need to provide the transaction data, the Merkle branch, and block of the creating transaction. Then, as a full-node, it is simple to check ...
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1answer
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What is the memory usage for checking transaction inputs?

Whenever a transaction is received by a node, the node verifies its validity. To that end, it checks for each transaction input whether that input is part of the UTXO set. It is my understanding that ...
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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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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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Why does bitcoind use a fork of LevelDB for key-value storage?

Since 0.8 bitcoind uses LevelDB for the storage of the UTXO set in chainstate/ and the block index in blocks/index/. On github special branch of LevelDB can be found: https://github.com/bitcoin/...
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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 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 ...