Questions tagged [consensus]
Questions about the consensus system of Bitcoin and the protocol rules that are consensus critical.
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What is the logic (if there is) behind linking the nSequence and nLockTime?
The nSequence transaction field was originally intended for a replacement logic, but since it was never well thought out, it was never implemented. However, it has been implemented since the beginning ...
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What does nVersion represent in Bitcoin transaction?
Have a few questions about the nVersion field in the transaction serialization format and they are related to the purpose of this field.
What does this field tell us? In the sense that if it is ...
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Are the blocks produced by different nodes in the network comparable in terms of the order of transactions contained in them?
Having a transaction from person A to B and another transaction from person C to D that both took place in more or less the same time I assume that there might be a situation in which different nodes ...
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Miners setting timestamps up to 2h into the Future
When a miner adds the Timestamp to a block template, it must satisfy two conditions:
Timestamp must be greater than the Median Timestamp of the previous 11 blocks
Timestamp must be less than its ...
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Undefined opcodes in bitcoin core defined as "Synonyms for OP_RETURN" in rust-bitcoin
In rust-bitcoin, opcodes past the 0xba opcode are named as such: OP_RETURN_187, OP_RETURN_188, ..., OP_RETURN_254. Their description is all the same: Synonym for OP_RETURN. The definition for ...
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Is there a well defined last block?
It's fairly well known when the last bitcoin will be mined, but is there a well defined last block?
By that I mean, is there a block height H after which Bitcoin Core nodes will refuse to accept any ...
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Is there a way to participate in bitcoin consensus (tx, block, mining, etc.) verification without downloading the ledger?
It seems like theoretically new blocks could be determined from the list of addresses and the amounts possessed by each address, where maintaining the blockchain would be optional and mostly for ...
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is consensus needed when double spend attacks cannot happen(assume ideal case)
Suppose double spend attacks cannot happen(assume senders, miners etc are all ideal actors) in a network like BTC for cryptocurrency transactions. I am assuming still fork can happen if two miners ...
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Why does everyone say that soft forks restrict the existing ruleset?
I understand that a key element of a soft fork is that legacy nodes will accept transactions from updated nodes. This is essentially the whole point of a soft fork as opposed to a hard fork.
But ...
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why not change bitcoin consensus code to reject transactions sent to previously used addresses?
Bitcoin has a growing issue of UTXO dust. Usually this dust occurs from companies trying to track bitcoin use, by sending dust or small transactions to previously used addresses.
There is almost no ...
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Looking for Source of an Old Idea About Subdividing Satoshis
I remember seeing an old idea but unfortunately I didn't bookmark it and now I'm struggling to find the source again. Maybe someone will remember it and be able to point me to the source?
It was ...
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What are Bitcoin's transaction and script limits?
What are the limits of different transactions and scripts (by consensus and standardness)?
Some stack exchange questions discuss some of them (but not all) and all these are scattered around.
What is ...
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Is the nVersion=3 policy proposal introducing additional policy rules and going against the policy principle to only relax policy rules?
In the PR review club on "nVersion=3 and Package RBF" (February 22nd 2023) glozow stated:
But in policy we want to strictly loosen rules. Otherwise we could accidentally censor transaction ...
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Do nodes accept non-standard output scripts in a mined block?
As I understand, transactions with non-standard output scripts won't be propagated through the network. I'm wondering if I were to mine a block with weird transactions whether it would be accepted by ...
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Does the coinbase transaction have inputs?
I was wondering if I can add dummy data into a coinbase transaction’s inputs.
Is it possible to do this? Can you insert invalid input scripts into a coinbase transaction? Can you add multiple inputs ...
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Does version of Bitcoin Core determine my consensus?
As far as (voting) on the network?
I run a full node, but do not mine.
I hear people say we have a choice when changes are made.
Is it the version of Core that determines that?
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Why CHECKMULTISIG bug can't be solved?
I was reading Mastering Bitcoin and I read about a bug in CHECKMULTISIG. If the starting ideas of this command should work like this
<Signature B><Signature C> M <Public key A><...
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Does Bitcoin need future consensus change upgrades or could a billion people use Bitcoin today?
Do Bitcoin Core and other base-layer implementations necessarily need further upgrades in order to become sufficiently fast and efficient to process the volume of transactions that you and others ...
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Why exactly would adding further divisibility to bitcoin require a hard fork?
There are quite a few threads already on this topic, but they all focus on the necessity or possibility for such a change. I understand that, even though it is difficult and would obviously require ...
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What is the use of longest chain consensus rule?
I want to know Couldnt a chain be hardcoded in the bitcoin rules itself? Only so and so chain can be used. During the early days of bitcoin, I know a small group of enthusiasts were miners. And they ...
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Can you attack the network in a UASF-way?
Let's say that an attacker wants to deploy a softfork, that isn't desired by the majority of the Bitcoin users. Can he enforce that softfork in a UASF-way, essentially flooding the network with nodes ...
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persistence of the RBF bit in post-fullrbf chain
In case consensus decided to ignore pro-zeroconf nodes (in case that is or can be a thing),
then what's the point of having the RBF bit in a transaction, if everything in the system is enforcing RBF (...
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Do non-Segwit nodes reject Segwit transactions with invalid signature?
As far as I can tell, non-Segwit nodes receive anyone-can-spend transactions, and thus come with no signature to validate. If a miner included a Segwit transaction to a block with invalid signature, ...
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consensus on the moving average [duplicate]
I research on consensus and need a forced delay between submittability of new blocks.
In bitcoin you use stochastics + processor clock speed. This allows you to choose an expected forced delay, which ...
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Is every BIP actually a small fork?
What precisely do we consider as fork?
It seems that every BIP can be seen as a fork, at least a soft fork since a lot of BIPs indeed are backward compatible. How big or impactful something has to be ...
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Relation between PoW and integrity?
I'm pretty new to the Blockchain technology. In a video that I watched, the lecturer talked about Consensus Algorithms and said that they're used for maintaining the integrity of the blockchain.
Then ...
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what guarantee that miners will only include valid transactions in a block?
So, miners, if I got it right, before inserting a transaction into the Mempool, will request an arbitrary number of confirmations of full nodes that will search the entire blockchain to see if a ...
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The competitive practicality of Bitcoin
Bitcoin is to be trustless by the thousands of nodes, but is this no more trustless than the Federal Reserve system? An account size in 8b on each device is a feasible alternative with absolute ...
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When was the 10,000 B limit for scripts introduced?
The file src/script/script.h defines a MAX_SCRIPT_SIZE of 10,000 B. Among other instances, the MAX_SCRIPT_SIZE is used in the IsUnspendable() check, which allows us to avoid adding outputs with ...
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Would a consensus algorithm like the one I describe work?
Given n nodes(miners/validators),
Every unspent transaction output is broadcasted to all n nodes.
Each node will select a batch of transactions and add it to their
block. The specific mechanism of ...
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Is there code in libsecp256k1 that theoretically should be moved to the main Core codebase?
In this question on libsecp256k1 Pieter Wuille stated:
libsecp256k1 provides implementations for all kinds of operations that involve private keys, public keys, or both. That includes key generation (...
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Is the removal of Bitcoin checkpoints considered a hard-fork?
The value of DEFAULT_CHECKPOINTS_ENABLED is true and changing it will allow nodes using the default settings to accept blocks that would be currently rejected during a potential reorg. Is this change ...
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When was proof of stake theorized?
Hi l've seen a while ago that Proof of stake concensus mechanism was theorized a while ago (before proof of work) in distributed systems. But I can't find any source of that, while searching 'proof of ...
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Was the addition of OP_NOP codes in Bitcoin 0.3.6 a hard or soft fork?
I'm doing some deeper research into historical consensus changes and it seems like most folks consider the addition of the OP_NOP codes to be a hard fork. Here's the diff for their addition: https://...
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Why is the intersection of two quorums must be greater than N/3 when proving streamlet?
Why is the intersection of two quorums must be greater than N/3 when proving Streamlet, a blockchain consensus protocol [BY Chan, Elaine Shi, 2020]?
In Streamlet, honest node vote for proposed block ...
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In future will multiple widely used implementations around libbitcoinkernel be an overall net positive or net negative for the ecosystem?
Assuming the libbitcoinkernel subproject of Bitcoin Core is completed and successfully/safely extracts the consensus engine out of Bitcoin Core will having multiple widely used alternative ...
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Is there a consensus as to what is meant by 'Nakamoto Consensus'?
I sometimes hear that bitcoin's key innovation was the Nakamoto Consensus, which solves the double-spend problem without the need for trusted third-party intermediaries.
I take Nakamoto Consensus to ...
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What stage of the bitcoin protocol deals (or 'solves') the double-spend problem?
I understand that a key innovation in bitcoin is that it solves a key problem faced by previous attempts at a digital currency: the double-spend problem.
In addition, I also understand that the ...
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Does every single node in the blockchain validate the transactions in the mempool?
I have read several responses to various questions SE. Some responses partially respond to the question so I was hoping to get your help to bridge my gaps in understanding.
Does every single node on ...
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Is the minimum fee consensus, just policy, or both?
Intuitively, I think minRelayFee is policy while minBlockTxFee is validation, but DEFAULT_MIN_RELAY_TX_FEE is in validation.h while DEFAULT_BLOCK_MIN_TX_FEE is in policy.h.
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Criteria for Bitcoin protocol consolidation/freezing at the network level (full nodes)
In the Bitcoin development process, there exists the following high-level structure of control:
Anyone can submit a BIP that aims to change Bitcoin Core
The BIP must be approved by an editor
The BIP ...
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How blockchain consensus verify the transaction?
So many blockchain documentation tell that the blockchain uses the consensus to verify transactions. But what I understand the consensus only generate the hash to create the new block. I don't know ...
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Does the reference client Bitcoin Core determine the consensus rules?
Does the reference client Bitcoin Core determine the consensus rules? Why should we care what is in the BIP if when there is a discrepancy between the BIP and the Core codebase (like we saw recently ...
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Can you get the longest chain by keeping a constant low difficulty?
I'm struggling with this question that should be easy to answer.
If the truth is the longest chain,
what if I redo all the work from Block 1
until I have the longest chain by keeping a constant low ...
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Verifying Block 124724
Just for my own educational purposes, I'm writing something that verifies the blocks on the blockchain. I had in my code this line:
assert coinbase_amount == block_reward + total_tip
And it succeeded ...
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Was Bitcoin 0.3.7 actually hard-forking?
Reading through the wiki (bitcoin.it consensus versions) I noticed that release 0.3.7 ("scriptSig + scriptPubKey evaluations separated") is listed as a hard-forking change. In BitMEX's ...
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How do bitcoin nodes rollback state when a higher POW chain is introduced
Let's say the current chain consensus has a total POW of X... this is agreed upon by all 10k+ BTC nodes.
A new "magic" node joins and it has mined a chain (privately) with total POW = 2*X. ...
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Why is CAmount a signed integer?
Is there is reason why Bitcoin uses signed instead of unsigned integers for amounts? I can't imagine a scenario where negative amounts could come up. Was it simply something Satoshi implemented for ...
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What is the standard logic behind the ordering of outputs in the vout array for a transaction?
This question and its answers discussed the meaning and purpose of the vout array of a transaction in good detail. However, I have so far not been able to find any good information about how outputs ...
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If two miners come up with two valid nonces, how does consensus take place?
I am trying to understand how the consensus mechanism works. My understanding is that multiple nonces can satisfy the target hash requirement. What I'm trying to understand now is: if two miners come ...
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