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DannyHamilton You would agree if you already know who he is and his contributions ,if you don't below are the 10 posts quoted which I think makes him qualify for a merit source.
Quote 1 :
Is such attack possible in theory?
No.
if not, then why?
There are 2 reasons.
The most important reason is that the consensus rule does
NOT state to follow the chain with the most blocks. That is just an oversimplification that people use when talking about the blockchain because it works in the general case and it is easy to say and understand. The ACTUAL consensus rule is to follow the chain that has the largest total proof-of-work. Since your blocks will be solved at a lower difficulty level, the total proof-of-work will be less than the "real" chain even though your chain has more blocks.
The secondary reason is that Bitcoin Core (and any other node or mining software that is 100% compatible with Core) has checkpoint hash values that it compares against the blockchain. Any chain that doesn't match those checkpoints is discarded.
if so, what effects would it bring to BTC? and how would we prevent it??
It brings no effects since it isn't possible. We prevent it as described.
I've originally wanted to test this idea in a local setup before bringing it to public, but I don't have enough technical knowledge to implement it.
You've saved yourself a lot of wasted time and effort.
It's a easy question:
Imagine 2 nodes, they two have different transactions on them.
Node B finish to mine the block first, it broadcasts it and the network accept it.
Ok.
Would this node inmediately continue proof of work even if the transaction pool is empty?
Lately, the transaction pool is never empty. There are more transactions than fit in a block. Therefore, there are always more transactions waiting for the next block.
However, if the transaction pool was empty, the miner can create the transaction that pays himself the block reward, and then build a block from that transaction. Therefore, a block always has at least 1 transaction in it.
What would happen if he mine the block and new transactions would come in?
Do you mean that he is in the process of mining the block, but has not found the solution yet? Or do you mean that he finished mining the block, has the solution for the block that has only 1 transaction in it, and then before he can broadcast it, more transactions come in?
If he hasn't found a solution yet, then he can build a new block header from the new transaction list and start mining on that new header. This way, if he solves the block, he can increase his revenue with the additional transaction fees.
If he has just found a solution, then he can immediately broadcast the block that has only one transaction, and then immediately start a new block with the transactions that he has just received. That way he can collect the block subsidy that he has already earned.
He would to start again with the new transaction because the tx are included in the block so the hash of the block changes, so he each time new tx are added the node has to restart the PoW, Right?
Every hash attempt is a new start to the PoW. It doesn't matter if you have tried a million hashes, or one hash. In either case the next hash attempt is equally likely to be successful. Therefore, there is no wasted effort to start with a new block header.
Unless the miners wants to waste his resources, they won't discard a valid block even if new transactions with larger fees gets relayed to them.
When you say "valid" block, I assume you are talking about a "solved" block? In that case your are correct. The miner just broadcasts the solved block and then immediately starts on a new block with the transactions in it.
On the other hand, if you are talking about a block that has been built , but which has not had the proof-of-work solved yet, then there is no waste of resources to discard the current unsolved block and start over with a new block.
There is no restrictions about how many transactions a miner should include. He is free to decide.
There are two legacy restrictions and one new restriction.
Legacy Restriction 1: The block MUST contain the "coinbase" transaction.
Legacy Restriction 2: The total number of bytes in the non-witness portion MUST be less than one megabyte.
New Restriction 1: The total block weight MUST be less than four megabytes.
Hello Everyone,
I want to know what is Double spent in bitcoin, and if you can sign a transaction while you don't have sufficient balance (in this case the transaction won't be confirmed ?)
REAL "double spend" is a situation where two (or more people) are paid with the exact same cryptocurrency funds, and it is not possible to determine with certainty which person was paid first (or which person gets to keep their payment. Each participant has now way of knowing if their payment is any good or not, and the entire system has no way of resolving the situation.
REAL "double spend" is not possible in Bitcoin. The reason that Bitcoin became popular and useful is because it is the first decentralized
solution to the double spend problem.
Bitcoin uses the "confirmation" process to allow the entire system and all participants to come to a consensus about the ordering of transactions so that everyone can know with certainty whether any transaction is valid or not.
However, Bitcoin (and many other cryptocurrencies) have a time delay between after the transaction is created and shared before it is confirmed. During this time, it is possible for there to be multiple transactions that are all trying to spend the exact same cryptocurrency funds. The
COMMON USE of the terms "double spend" within decentralized cryptocurrency communities is to refer to these competing unconfirmed transactions. Only one of them will ever confirm, and then the others will become invalid and will be rejected by the system, but during the time that the transaction is waiting to be confirmed it is possible to have multiple "double spend" unconfirmed transactions.
You can sign any transaction you want. But, if the transaction is not valid, then it will be rejected by ALL participants in the Bitcoin system.
Bitcoin should be viewed as a financial asset or currency?
Yes.
When you hold bitcoin as an asset and exchange it for a local currency in order to spend it, then you are viewing it as an asset.
When you hold bitcoin as a currency and spend it to purchase products and services, then you are viewing it as a currency.
It is both. It is neither. It is something new that didn't exist before. The way you should view it will depend on the way you plan to use it.
Oh hold on.. need te rescan aswell.. fingers crossed...
Correct.
Zapwallet removes ALL transactions from the wallet (confirmed, unconfirmed, sent, and received).
Then when you re-scan, the wallet finds all of the CONFIRMED transactions (both sent and received) in the blockchain.
The end result will be that your wallet should ONLY have CONFIRMED transactions and that the balance should reflect the total amount of confirmed transactions you received minus the total amount of confirmed transactions that you sent.
Note that it is possible for someone else to keep a copy of any unconfirmed transaction that you have ever broadcast to the network. As long as that unconfirmed transaction is still valid, they could re-broadcast it without your permission. Therefore, it is possible that, at some time after the re-scan, an old unconfirmed transaction could show up in your wallet again.
Appreciate the continued help, Danny - how can I push a raw transaction to their mempool, that was apparently sent via the Blockchain web wallet?
You can get the raw hex transaction from blockchain.info with this link:
https://blockchain.info/rawtx/9a2a0b1ba7949447acfba20829b1eda303828f172b1bbbf3c11101f9b7670b61?format=hexIn case you ever need to find the raw transaction at blockchain.info yourself...
Just change the usual /tx/ in the URL to /rawtx/ and then add ?format=hex to the end of the URL.
You can copy the transaction from there, and then paste it into the text entry box at the viaBTC link I provided.
Transactions are broadcast and then are typically received by the payee's wallet within a few seconds.
The process is a peer-to-peer relay of the transaction throughout the network until nearly every participant has received the transaction.
At that point the transaction is described as "unconfirmed". The recipient can then decide if they are willing to rely on the unconfirmed transaction based on any trust-relationship they have with the sender.
Meanwhile, the miners (as participants in the system) will also have received the unconfirmed transaction. Each miner (or mining pool) will prioritize the transaction for themselves based on any criteria they choose (since they are profit motivated they generally choose to prioritize based on fee per byte, or fee per block weight unit). They then choose the highest priority transactions and fill the block that they are working on with those transactions. The first miner (or pool) to complete the proof-of-work will broadcast the block of transactions, and then all miners (and pools) will begin again with their list of unconfirmed transactions.
Once the transaction is included in a completed block, it will be described as "confirmed" with 1 confirmation. At that point it will generally be safe for most recipients to rely on the transaction regardless of the trust-relationship they have with the sender. If it is a high value or high risk transaction, then the recipient may choose to wait for additional blocks to be added to the blockchain on top of the block that includes their transaction. Each additional block added to the chain is considered to be an additional "confirmation" of the transaction.
The amount of time that it takes to get one or more confirmations is variable. With a high enough transaction fee, the transaction will typically be (but is not guaranteed to be) included within the next 3 blocks or so. The amount of time that it takes to complete a block is random, but the long term average is about 10 minutes. Any individual block could be much faster or much slower than that.
Quote :8
According to the following website:
https://bitcoinfees.earn.com/The fees necessary for fast confirmation
right now are approximately 490 sat per byte.
Your fee of 96 sat per byte is clearly too low.
The other transaction can NOT confirm until the earlier transaction confirms.
Paying a higher fee on a later transaction when spending unconfirmed bitcoins is called Child Pays For Parent (CPFP). The idea is that the fee on the second transaction can be high enough to pay for BOTH transactions.
Total bytes for the two transactions together is 1337 bytes.
Total fees for the two transactions together is 203237 satoshis.
203237 / 1337 = 152 satoshis per byte for the two transactions together. Still to low for the current network conditions.
Hopefully the acceleration from bob123 will help.
Yep, thank you. So a copy of an HD wallet saved in a safety deposit box, will always have the same balance as the original, no matter how many transactions and addresses are made? and the password isn't changed.
As long as the password hasn't changed... Yes.
The copy will be capable of generating all the same private keys, and then can scan the blockchain to determine which bitcoins is has control over.
Of course, if you've forgotten your password you'll have difficulty spending any of it, so make sure you pick one you'll remember.
Of course, if someone else gains access to that copy and can determine your password, they'll have access to all your bitcoins even if you still have your original wallet. So, make sure you keep that copy secure, and use a password that will be difficult for someone else to guess or brute force.
Horses for courses.The difference between someone who knows a computer language and can write a computer program, and an experienced, talented, skilled, developer is that the skilled developer is able to look at a particular use-case and determine the best (or at least a very good) option for how to implement it.
There are situations where a centralized database it the best choice. There are situations where a decentralized blockchain is the best choice. Anyone who blindly chooses one over the other without considering the benefits and requirements is a fool.
These are just some of the posts that shows how detailed and informative Danny is no matter how simple/complex the question is.Please let the deserving members get to the source list.Thank you.
