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20 votes
Accepted

Why can't mining pools provide fake transactions within the generated blocks?

Suppose Alice wants to add a fake transaction where she receives X ammount of BTC. I understand that in order to add that transaction to the blockchain she would have to compete against all the other ...
Nate Eldredge's user avatar
10 votes
Accepted

What are miners signalling for when the block header nversion field ends in 4 i.e. 0x3fffe004?

They are signaling for Taproot. BIP 341 specifies that signaling occurs on bit 2.
Ava Chow's user avatar
  • 70.5k
9 votes
Accepted

How does the network protect itself against attacks where one miner with a lot of hashing power lies that it takes 10 minutes to create a block?

What you describe is a (variant of a) majority attack: if an attacker can construct a block every 3 minutes while the rest of the network can only construct a block every 10 minutes, that means the ...
Pieter Wuille's user avatar
8 votes
Accepted

If you have the required mining power, is it possible to mine your transaction in the next block without propagating it to the network?

Yes, since miners (pools) construct the blocks they mine, they can insert any valid transactions they want, including transactions that were never broadcasted to the wider network. They don't even ...
Vojtěch Strnad's user avatar
7 votes
Accepted

Preventing transaction fee collusion between large miners

In theory, preventing this problem is why miners exist in the first place. The sort of collusion you're describing can more generally be described as censorship: miners jointly deciding to delay ...
Pieter Wuille's user avatar
7 votes

Why does the hash-rate change so drastically?

The actual hash rate of the network is not (and likely cannot be) known. Blockchain.info and any other website that tells you the network hashrate is extrapolating it from the frequency that blocks ...
Ava Chow's user avatar
  • 70.5k
7 votes

Block Health at 94.82%, why do nodes accept this?

Why do Nodes accept blocks that have so many intentionally excluded transactions? Because nodes do not get do discriminate between blocks. If a block follows the consensus rules, it must be accepted. ...
Pieter Wuille's user avatar
6 votes

How does solving reduced difficulty hashes contribute to solving a block?

Contrary to popular belief, mining is not something where there is progress. Each hash has the same probability of being a valid block hash. You could get lucky and find a valid hash with your next ...
Ava Chow's user avatar
  • 70.5k
6 votes
Accepted

Mining Block header bit reversing

Let's take a look at this block, because it only has one transaction (the coinbase): 000000000000000000eb2d0ed97a7b2cff7f1408417dca83908004beb6fd9b95 Let's grab the raw hex data: ...
meshcollider's user avatar
  • 11.8k
6 votes

How does mining pool ensure the miner works on the problem?

Miners regularly send "shares" to the pool server. The shares are solution to a low-difficulty bitcoin puzzle. Each share stands some chance of being a solution to the current bitcoin puzzle, of much ...
Charles Bouillaguet's user avatar
6 votes

Why does a bigger block size infer miner centralisation?

Because a key aspect to understand is that transferring a block over the network globally is not completely instant. The bigger the block is, the longer the block propagation statistically takes. ...
user44404's user avatar
  • 546
6 votes
Accepted

How do mining pools ensure pool members don't cheat?

The work given by a pool includes the coinbase transaction which defines the payment as going to the pool, and is unique to that. If the client modifies the payout address, the proof of work they have ...
Claris's user avatar
  • 15.4k
6 votes
Accepted

Why are miners setting the locktime in coinbase transactions?

Wang Chun of f2pool (@satofishi) said on Twitter: “We repurpose those 4 bytes to hold the stratum session data for faster reconnect.” He went on to say: "The coinbase locktime is set to: ...
bordalix's user avatar
  • 512
5 votes
Accepted

Keeping valid shares for it's own when mining in a pool

The address the block reward goes to is in the data that is being hashed. That address is the pool's. If a miner finds a hash that meets the block difficulty, changing the address to the miner's own ...
user36303's user avatar
  • 786
5 votes
Accepted

Does mining power of different miners add up in mining pools?

Mining is a lottery, not a race. The fastest miner doesn't always win. In general, if you have X% of the hashrate, you will find X% of the blocks. This is because not just all pools, but every every,...
Pieter Wuille's user avatar
5 votes
Accepted

How miners with less power win?

That said, when the next block is being mined, again the same person will win because of his computing power. No. Higher mining power means just higher chances to mine a block. If there are 3 miners:...
hardfork's user avatar
  • 2,117
5 votes
Accepted

How do we know which miner or pool mined a block?

We know which miner/pool mined a block only if that miner/pool chose to identify themselves. Most commonly, they do this by inserting their name or other recognizable signature in the block's ...
Nate Eldredge's user avatar
5 votes

Why has BCH not received a 51% attack yet?

Because of the cost, specifically the opportunity cost. If a miner has 10% of the BTC hashrate, then if they pointed all of that mining power to BCH, they would still be losing money. With 50% of the ...
Ava Chow's user avatar
  • 70.5k
5 votes
Accepted

Do pools distribute "jobs" to miners based on "failed" solutions which have already been submitted?

I've read simplistic descriptions of mining as simply incrementing the nonce until a solution is found, but I've also read much more detailed explanations which would imply much more is involved. Even ...
Ava Chow's user avatar
  • 70.5k
5 votes
Accepted

Are there still miners or mining pool which refuse to implement SegWit?

No, in the past year, there were only 15 non-empty-non-segwit blocks mined which account for less than 0.03% of all blocks. Non-empty blocks without segwit transactions I've looked up the last ...
Murch's user avatar
  • 75.5k
5 votes
Accepted

Can a bitcoin transaction from a specific bitcoin address be banned? (via mining pools)

Yes, miners can censor transactions. A mining pool (or solo miner) can choose to not add a transaction to any blocks that they create. And, of course, this can be done dynamically so that transactions ...
Ava Chow's user avatar
  • 70.5k
5 votes
Accepted

Why can't default minimum fee rate be changed to 0.1-0.2 sat/vByte?

The primary reason for the minimum feerate (and related things like the discard feerate) is preventing the use of the P2P network as a cheap global broadcast system. If it's easy to produce ...
Pieter Wuille's user avatar
5 votes
Accepted

Does bitcoin mining pool hash randomly and separately

Most mining pools use the stratum protocol. Part of this protocol includes a field for part of the extraNonce, named extraNonce1. The extraNonce is just extra data that is put in the coinbase ...
Ava Chow's user avatar
  • 70.5k
5 votes
Accepted

How bitcoin miners choose timestamp in block header when mining?

My original understanding of mining is to pick a timestamp (the timestamp of when miners started mining) and then fix it. There's no reason for that to be the case, as mining is progress-free. It is ...
Claris's user avatar
  • 15.4k
5 votes

Information available to bitcoin miners in processing transactions

Miners have all the information about a transaction as anyone else looking at the pool of unconfirmed transactions (or the blockchain in case of confirmed transactions). From the transaction data ...
Vojtěch Strnad's user avatar
4 votes

Bitcoin mining - is it a race and how to not waste resources?

Yes and no: Yes, the first one to find a block gets the whole reward and the others have wasted their effort. But there is no progress in mining, so every attempt to build a block has the same chance ...
Murch's user avatar
  • 75.5k
4 votes
Accepted

How much power and cost do miners currently expend to mine one bitcoin?

Power usage per GH/s changes with every new ASIC product. I believe the Antminer S9 is probably still the state-of-the-art in december 2016. Batch 23 of this miner does 14 TH/s with 1372W +10% (at ...
Dr.Haribo's user avatar
  • 8,439
4 votes

Is Light Bitcoin a legitimate site or a SCAM?

There is no mention that they are doing mining at all, nor a figure for their current mining power, or blocks that they found, just some vague explanations that they are investing any deposits and ...
Murch's user avatar
  • 75.5k
4 votes

preventing fraud in a mining pool

The very last line of a block effectively contains: Reward for Solving this Block: Add 12.5BTC to Account for [Mining Pool]. If the miner tried to change that line to read Reward for Solving this ...
abelenky's user avatar
  • 1,344
4 votes
Accepted

PPLNS implementation

Well, that post is quite old. Variable-difficulty shares weren't a thing then. That said, I'm pretty sure the fix is as follows: When a share is submitted, the post says you should assign to it a ...
Meni Rosenfeld's user avatar

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