G. Maxwell
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Reference an UTXO of a transaction that has not been yet mined
3 votes

Worth keeping in mind: Unless all inputs to the original transaction are segwit and at least one is sighash all, the original transaction will be vulnerable to third party malleability so your second ...

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Accidentrally spent from unconfirmed transaction
3 votes

There is nothing wrong with spending unconfirmed outputs. Bitcoin core will happily spend its own unconfirmed outputs, though it does prefer not to if it has a choice. Your transaction can't confirm ...

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Is there a max number of tx outputs allowed by consensus?
3 votes

There is no direct limit on the number of outputs, but transactions can't have more than an allowed amount of weight and this indirectly limits the number of outputs.

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How long does it take to validate a full block?
3 votes

Your question doesn't actually provide enough context even with the proviso that you don't care about which machine specifically. Do you mean cold-cache during initial block download or do you mean ...

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Bitcoind address index
3 votes

The scantxoutset RPC in 0.17+ will do what you want, although unless you batch query several addresses at once it may be a bit slower than what you were asking for.

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What is the optimal Bitcoin Core 0.17 settings in bitcoin.conf settings for running a full node with a very beefy system?
3 votes

dbcache is the only significant performance influencing option. Performance may be improved somewhat by increasing receive and send buffer sizes. You don't specify exactly what application's you're ...

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How come Merkle tree is more efficient when tree branches are not stored in blockchain?
3 votes

The speed of the hash is roughly linear in the number of bytes processed: SHA2 processes block of 64 bytes at a time, and the time taken is equal to the number of blocks processed. Computing a ...

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Does a Block contain the list of transactions? Or only the Merkle Tree?
3 votes

In order to validate a block nodes must have the actual transactions themselves, even a list is insufficient. But the question "Does a block contain X" is a bit like asking "What is the sound of one ...

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Does BIP39 mnemonic construction avoid repeating words?
3 votes

No, the BIP39 construction does not avoid repeating words. It is possible for a word to show up multiple times, but since there are 2048 words it is fairly unlikely for repeats to show up in randomly ...

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I mistakenly deposit my BTC to my BCC address. How can i get it back?
3 votes

You will need to contact HitBTC and ask them to correct it. In theory they have the private keys and can recover these coins in a way similar to splitting Bcash and Bitcoin in the first place, but ...

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How do transaction fees exacerbate instability in Bitcoin in the future?
3 votes

As Nick answered quite adequately: After subsidy has diminished sufficiently as soon as a block is mined that clears out the mempool there will be no income for a miner that mines a successor block, ...

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Why hasn't cold storage (offline signing) been supported by Bitcoin Core (GUI) up till now (0.19.0.1)?
2 votes

Prior to segwit doing this securely required carrying around enormous prior transactions. Prior to PBST there wasn't a standard serialization that covered all the interesting use-cases. It's been ...

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Including transactions in a block - rules and time / technical aspect
2 votes

There really isn't any "starting over" in mining, because mining is effectively progress free, like a lottery and unlike a race. Nothing is lost when updating the transaction list, other then the ...

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How to calculate the risk-free rate of cryptocurrencies?
Accepted answer
2 votes

Bitcoin itself has no returns: 1 Bitcoin is worth 1 Bitcoin, always. Presumably you actually want to discuss the returns of a Bitcoin plus ordinary currency pair, such as BTC/USD. In that case you'd ...

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Does parent also pay for child?
Accepted answer
2 votes

Does it also work the other way - that is, does transaction with high fee pays for child transaction that has low fees, given that they are both in the mempool? Or is the policy only "one way", from ...

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Confirming transactions in the Merkle root and SegWit
2 votes

But how would someone know which associated transaction is required to hash with your transaction to confirm its validity? And where would you get it from? Your question is a little vague, it sounds ...

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Why are exactly 4 bit windows used in the lookup table of libsecp256k1 to speed up point multiplications?
2 votes

What you are talking about is the table used for constant time operations w/ secret values, e.g. for signing and key generation (see the heading "Point multiplication for signing"). To prevent ...

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What will happen if all bitcoin nodes are pruned?
Accepted answer
2 votes

If all nodes were pruned a new node would keep making connections looking for an unpruned peer forever and fail to sync. If instead almost all were pruned it would simply take a longer time than ...

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What are the advantages of using Secp256k1?
Accepted answer
2 votes

What are the advantages (and disadvantages) of using this over other specifications such as secp256r1? Secp256k1 is less widely used than secp256r1 so for some time there were faster implementations ...

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Serialized transaction bigger than the actual transaction object? CVE-2013-4627
2 votes

Yes. The attack was adding junk to the end of otherwise valid transactions to cause the junk to get relayed around. (as an aside, if we hadn't fixed that, segwit would have been easier to deploy...)

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BIP 144 transaction format and soft-forks and old nodes
2 votes

When an old node connects to a new node the new node detects that the old node doesn't support the new transaction format and so it converts any transaction it sends it-- e.g. segwit transactions in ...

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double spend attack: Is this actually true for the more time progress the higher the probability of success for attacker
2 votes

I believe you are asking if the inter-block interval matters for the success rate of a high hashpower reorg attack. It does, because if it is too fast the honest participants will spend a substantial ...

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How do miners send blocks to network peers?
2 votes

Blocks are usually sent using BIP152. This transmits blocks using an 80 byte header, 6 bytes per transation, plus the coinbase transaction. To give a concrete example block ...

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Error while send transaction: Data push larger than necessary
2 votes

Your transaction is failing validation with SCRIPT_VERIFY_MINIMALDATA, which is described in BIP 62 rule 3 protections against malleability. CheckMinimalPush() requires a push of 0x01 to be done ...

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How segwit blocks are seen by segwit and non-segwit nodes?
2 votes

There aren't two part to a block like you describe. The word segregated in segwit means that the witness data isn't included in the TXID computation similar to how it always wasn't included in the ...

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Why is the nonce bruteforced from 0 to n while mining?
Accepted answer
2 votes

It doesn't matter which nonces you test or in what order that other than you need to avoid testing the exact same block header twice (since that would obviously be a waste of time). It's useful to ...

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Reject transaction because of illegal data
2 votes

There have been miners that rejected transactions with OP_RETURN because its unnecessary spam. Virtually every node and miner limits OP_RETURN outputs by size. The amount of data relayed or allowed ...

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What is the network topology used at the physical layer of the Bitcoin network?
2 votes

the performance of the Bitcoin Network under various network topology and for which it performs the best Bitcoin must be secure, foremost, and if it isn't the 'performance' would be totally ...

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Does my segwit node only have segwit blocks?
Accepted answer
2 votes

BIP 144 equipped nodes doesn't fetch blocks from old nodes since they are only capable of providing witness stripped blocks. If someone sent it a stripped block (e.g. by lying about their support or ...

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Signature generation
Accepted answer
2 votes

No, only two hashes. The hash itself isn't typically described as a part of ECDSA though the input must already be hashed (because e.g. a signature of 0 is trivially forged).

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