Miner transaction selection considering sigops

There is a limit on how much a block can sigop (set to 80000?). There is also a limit on how much a single transaction can sigop (set to 16000?). It thus seems possible (and if it’s not possible, the remaining of this question is void, but then how is it prevented?) that an attacker submits five special transactions to consume the whole block sigop limit. If such attacking transactions are using very generous fees per byte, if the miner chooses which transactions to include in a block based on fee per byte metric, it would include the attacking transactions in a block, getting relatively huge fees per byte, but not filling the block because of sigop limit. This would mean that the miner could get more in fees if it avoided attacking transactions, but the question is whether such selection avoidance is implemented by default.

Can you make profit from a miner?

Someone named mr_richard665 on instagram told me he was a bitcoin broker that worked with bitcoingroup and that he could help me make 30% profit everyday from my investment if i let him manage my account by me sending my bitcoin investment to his miners wallet address,is this a scam?

If fork is happenedand and propagateted, miner in mining pool receives same block?

For example there are 2 mining pools A and B and they mined block in same time

Then A mining pool got a block that A mining pool mined?

Or nodes in mining pool receive independently so they select block regardless of mining pool?

I have known nodes choose a block which are propagated early to them and block is propagated not geographically close node but randomly(i mean block is propagated close nodes but this ‘close’ do not mean geographically close but close in network)

When miner is mining or propagating, miner can recognize which node is mining in same mining pool?

What happens if a miner receives a block but not its previous?

Suppose the following:

  1. A miner has stored the current blockchain A-B-C.
  2. It stops listening for blocks during some time.
  3. During that time, blocks D and E are mined and broadcasted.
  4. The miner reconnects and immediately listens to the block E, before even knowing about D.

Will the miner simply ignore that block? And, how will the miner update to A-B-C-D-E (step by step)?

How to change Bitcoin’s proof of work? Then enable miner

I’m using https://github.com/jgarzik/pyminer/blob/master/pyminer.py to test a few different hash functions. Instead, I’d like to try keccak, a few of them in some order like an “X5” and so on.

This is a toy project to try and change the proof of work in Bitcoin and recompile and test, either an old version < 0.10.0 since getwork() might be easier to test with, or the latest release – apparently bitcoin-cli can mine blocks if starting from a new genesis block and the difficulty is set so low that a CPU can mine as much as you like.

My problem is that I can’t find in Bitcoin Core where the proof of work is. I’ve looked in pow and validation files for near a week now, but no luck so far, or I just can’t see it for some reason.

I thought it might have been obvious in miner.cpp which I think is no longer used (but might be able to be enabled?), and the best I can find is CheckProofOfWork in pow.cpp.

It doesn’t seem to check whether the PoW is sha256d. Does it? I must be missing something. So it looks like I can just change the miner code and submit a proof of work and if it meets the requirements, it will be accepted.

Is there a reasonably easy way to use a toy miner, change the PoW algorithm, and modify Bitcoin Core if necessary to try a different proof of work?

I mined in early 2010 with a cpu miner and just found my keys after forgetting all thease years, no joke need info please

So a few things, what was the mining program from the devs back then? I remember a pop up kinda like a dos window and it dispalyed the key and said somthing like write this down we will not give it to you again… I also remeber a pass sentance proram that could be used to recover somthing if you entered in you full sentace string..

I have been out of crypto since I mined a few blocks way back then and I have my keys so do i just download and sink the wallet first? remeber I did this long ago and was hoping to located the mining program from way back then to read the readme and refresh my memory. Also back then you could contact a dev to help you,, thanks in advance for helping out a old man trying to pay a few bills.

How miner makes sure that a transaction he picked up from mempool is actually valid? [duplicate]

This question already has an answer here:

  • How is a bitcoin transaction validated? 1 answer

I have read and searched enough about the roles and responsibilities of miners here; For example: Does the miner first validate transaction before doing POW or he does not validate at all ?

Does a node validates a transaction that comes with a block if it's already in its mempool?

But this part is still a bit unclear to me. If a miner confirms a block that has an invalid transaction then he will not only waste too many resources in doing the PoW but he may also get penalized for that, so he validates every transaction. Does that mean that if mempool contains a transaction saying “A” gave “B” 0.1 BTC then miner is supposed to actually make sure that “A” has that much unspent BTC before he can select that transaction into a block to be mined? If a miner has to validate each and every transaction like this then it will mean too much work, because the only way you can get a confirmed balance for any account is to literally start from the genesis block all the way to the current block. I understand that there are WebServices that give you balance for any bitcoin address but in turn they must be traversing the whole blockchain. So the question is does the miner actually makes sure that “A” had enough unspent BTC before this transaction or does it perform some other simpler check, before selecting and transaction from the mempool.