Bitcoin Basics - Discussion

Blockchain and Bitcoin 101
#719

Question regarding mining competition:

In Mining PoW & Incentives, it is explained that miners compete with each other to get their completed block appended to the chain, and that their respective blocks do NOT have to contain the same transactions. M1, M2, and M3 are each competing and the winner’s block is added to the blockchain. HOWEVER, the losers blocks are deleted.

Is it safe to assume that those deleted transactions are still in the mempool, to be taken and confirmed again by another miner (or, possibly, the same miner), until that particular transaction makes it’s way into the blockchain?

#720

Once a transaction created it can’t be deleted. Those transactions are returned to the mempool to be picked up in a future block. Stale blocks are usually not a serious threat to the network but they do leave room for fraud and attacks on the network, for example, a sender who’s transaction was a part of a stale block could technically endorse a second transaction to spend those same funds before the original transaction reprocesses. They could bolster this second transaction with a larger specified transaction fee so that miners are more likely to include the second spend in an upcoming block before the original transaction gets reprocessed.

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#721

Do we have simple and therefore small transactions with higher fees?

 - If so, why would that be? The sender's interest is to be charged as little fees as possible after all.

 - If we don't, then why does it matter for the miner if a transaction is small or large if the fee will proportionally grow with its size anyway?
#722

How do miners know what hash algorithm to use in order to get the correct hash for the block they are trying to mine once they have the right nonce?

#723

Transaction fees are based on the data volume of a transaction and the congestion of the network. A block can contain a maximum of 4 MB of data, so there is a limit to how many transactions can be processed in one block. A larger transaction will take up more block data. Thus, larger transactions typically pay fees on a per-byte basis.

Transaction fees also reflect the speed with which the user wants to have a transaction validated. When a user initiates a bitcoin transaction, it goes into the mempool. Upon validation, it is included in the block. Miners choose which transactions to validate and include in the block. When there is a backlog of transactions waiting to be validated, it creates an incentive for miners to process transactions with higher fee rates first. Most miners target transactions with high fee to byte ratios.

#724

Bitcoin uses the SHA-256 hash algorithm. To mine a bitcoin you will need Bitcoin Mining Software.

#725

Thx Maki. If the transaction fee is not purely based on transaction volume, then it explains everything else I think.

#726

Ah, so it’s a single and predefined hash algorithm that comes with the software. Ok, thx for the info.

#727

Hey! you mentioned in one of the lessons that Bitcoin is written by script.
What is bitcoin source code written in?

#728

The original Bitcoin Core source code is written in C++, and the up-to-date implementation can be found on GitHub

#730

everything looks clear to me and thanks for everything.this course is amasing.

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#731

I hope you guys are having a great day.

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#732

HELLO.

CAN SOMEONE EXPLAIN IS IT POSSIBLE TO HIDE ORIGIN ADRESS OR DO TRANSACTIONS WHERE YOU CANT FALLOW ADRESS WHO IS DOING TRANSACTIONS, EVEN ITS DIGITALY SIGNED WITH PRIVATE KAY’S.

HOW HACKERS CAN HIDE THIS IF THAY WANNA GET OUT/SEND MONEY(VALUE) AROUND TO THE POINT WHERE THAY CAN GET FIAT?

ps. I got in situation, where hackers asked to be payed in BTC so thay can hide the way of geting FIAT. (Not me personaly) Is it possible for tham to leave crypto with no trace?