New answers tagged blockchain
1
To state simply, you don't have enough money to send, your output was 4142 satoshi in the previous transaction but you need 22013 satoshi, try to find out if this is because of hidden tx fees or your trying to send from the wrong wallet/ transaction chain
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When miners build valid blocks with transactions, they put in significant amount of compute work to generate a hash of the block header that meets the difficulty requirement. Blockchain is a chain of blocks where each block header references the hash of the header of the previous block. The hash of the block header is calculated using all the elements of the ...
1
he is inputting any arbitrary values, in order to get a value that can be hashed into something with certain preceding zeros. When he got that value, he put that value into the blockchain and generate a new block.
It happens in reverse.
First the miner builds the new block itself. Then builds its header, then hashes that header. Also what the miner looks ...
1
SPV (lightweight) users do not have a chain. (Well, some SPV users have a fraction of the full chain, but some SPV users only have block headers. Am I correct?)
SPV clients only keep track of the block headers, usually rely on other nodes to do the block validity verification, and do not keep any full blocks around. This may seem similar to a pruned node ...
2
No.
Block data is written (appended to) blk*.dat files whenever a block is received from the network (assuming things like PoW and a few other sanity checks pass). As blocks are received in parallel from multiple peers, their order on disk ends up being chaotic.
Undo data is written when a block gets fully validated. As full validation requires validation ...
0
With order.
The world mined different block now, with the consensus only one remain in the network.
if you want to get some information from RPC bitcoin you should consider also the retard in your node.
You can call the method RPC getmininginfo but this command doesn't contain all information on the mining your are searching (an example Previous Block).
...
1
Lack of trust
A major difference over a traditional database system is that blockchains enable a "shared database" without having to trust the holder of that database.
It doesn't necessarily have to be a proof of work system like many cryptocurrencies but even for a centralized, shared database implementing it as a blockchain (in the technical sense of a ...
8
This is hard to answer, as "blockchain" isn't a very well defined thing. Often the term refers to some use of cryptography in a distributed system, but what it means beyond that depends on who you ask. To those who use it as a generic term, it is usually little more than a marketing term.
If you assume that at least there is an actual chain of blocks being ...
13
Blockchains are data structures, whose only advantage is that storing data in that structure allows you to achieve decentralization under certain conditions.
So your question reduces to "how is decentralization important"?
Decentralized systems tend to have the following favorable attributes:
Open (anyone can participate; not permissioned)
Borderless (as ...
2
First, a quick overview of what happens when you submit a transaction to the network:
Each node that hears about your transaction will check to see if it is valid according to their view of the network. If it is valid, the node may broadcast the transaction to its peers, and may add the transaction to its local mempool. If it is invalid, the transaction ...
2
If a node X receives first the blockchain from A, and it approves it, when it receives the blockchain from B, it simply reject it ?
It will keep the block locally as an alternate chain, but not immediately discard it.
If a node X receives first then blockchain from A, and then the B's blockchain in which also a node C has put another correct block (so is ...
0
Automated transactions are handled by the use of scripts. Scripts are used to automate the execution of tasks. Scripts use variables that hold values which are manipulated using conditional statements, loops and functions. Hence, the implementation of automated deposits and withdrawals of different currencies are handled by scripts
0
One way is to write software for each cryptocurrency as you suggest.
A lot of it would be reusable code as you can just interface via RPC with your wallets.
Another way is to use a wallet that supports multi currencies and then interface with that wallet.
But lets examine what really is required
depostis
those are essentially free as all you need is an ...
1
There is no "consensus algorithm" that starts and stops as you are asking. There isn't a timer and there isn't anything that nodes communicate other than blocks.
The process of updating the blockchain (i.e. the consensus algorithm) is always running and "wakes up" whenever a new block is received. It is run by nodes by themselves as there is no need to ...
5
To join the network, a Bitcoin full node will work its way through the network history, independently verifying the state of the network through time. So yes, each node will have downloaded and validated the entire transaction history, but a node can choose to use 'pruning mode', where it will discard unneeded transaction history after validation is complete....
1
Full nodes by default store the entire blockchain. The current size of the blockchain is ~250GB, so it is feasible for individuals to have their own copy and verify all of the transactions. There is also the option to run Bitcoin in pruned mode, which reduces the number of transactions that need to be stored. This greatly reduces the storage space demands ...
2
The question at this step is: does the wallet app perform any kind of transaction validation that requires to check the whole history of the blockchain at this level ?
It depends on the wallet.
In general, a wallet will likely do some validation as a sanity check to ensure that the transaction they create is valid and will be accepted by nodes on the ...
2
Your best bet is to report to the proper authorities.
Contrary to popular belief, Bitcoin transactions are in fact traceable. There is a slight chance that the scammer(s) proceed to make a mistake and withdraw the BTC you transferred in a way that sheds a light on their identity.
18
I'm sorry for your loss. As a 'tech person' reasonably informed about cryptocurrency, I concur that it is highly unlikely that you will ever recover any money.
Some information about Bitcoin and online scams
Technically, it is not hopeless though. You recovering (some) money would hinge on this chain of events:
It is not completely impossible that the ...
2
No, they’re completely incompatible.
42
How do I recover from a cryptocurrency scam?
You don't. At least, you don't recover your money. I guess you recover by learning from the mistake and doing things more safely in future. It may be worth asking an accountant if the financial loss on your investment can be offset against other taxable income.
I contacted my bank to see if they could do ...
9
Short of having law enforcement and the legal system whose jurisdiction the scammer(s) reside in compelling them to return the funds, you are out of luck.
Bitcoin transactions are irreversible. Once they have the coins in addresses for which you do not own the keys, there is nothing you can do to recover them.
Your only option may be to treat this as an ...
1
Considering that a block is mined on average every 10 minutes and that the average time to propagate to all nodes is 12.6 seconds, I think it is pretty fair.
We could also guess that the big miner have incentives to get the newly mined hash very fast so it must be lower than 12.6 for them.
0
In bitcoin blockchain, a miner would first validate transactions like making sure that the senders have enough balances in their accounts before adding the transactions to a block. Then the miner again will find the nonce of the block that will produce the desirable hash. After that, the miner will broadcast the block into the network. Other miners in the ...
4
esplora is just the web ui frontend, you also need to setup the (forked) electrs backend for indexing and for providing the HTTP API that esplora queries.
electrs can index the bitcoin block chain using two methods: by reading the blk files directly out of disk, or by querying for blocks using the bitcoind rpc. The first method is significantly faster, but ...
0
Yes, it will match. getblockcount is the number of blocks that you have already synced to, regardless of pruning.
0
You can just mount the data dir of your bitcoind on the second linux and point esplora to it ? (note that it will probably be very slow, better to allow esplora to access the data directly and not via network)
2
1- how do miners in a network learn that there is a new transction added in one block?
When a node recognizes a new block, it sends it to all the other nodes directly connected to it. It is very important for miners to build on top of the newest blocks they possibly can and to get their own blocks to as many other miners as quickly as they can (or they lose ...
0
Hi and welcome to Bitcoin stack
I will try to give an order to your question.
how do miners in a network learn that there is a new transaction added in one block? is there some party responsible for notifications or something? after getting this information, must a miner re-copy the whole blockchain to his local computer?
I think don't is wrong if I ...
0
correction Nov 15: There is in each block a coinbase transaction and it"s always the first transaction.
The mined coins show up and the balance can be seen in the explorers (miners reward plus fees). Not necessarily it's in the first transaction of a block and not necessarily a block needs to contain a miners reward, but in most cases it is there and it's ...
0
I suppose it just a succession of lucky event, even if this miner wanted to do a 51% attack, there is not a lot he could have done with it, except as you said break or reduce the trust in the bitcoin network, and someone who have invest that much money into mining equipment must own and will own lots of bitcoin and so have less incentive to try to break it.
4
Would you please clarify the reason behind the invention of Blocks?
When determining who owns what money, the ordering of transactions becomes important. If I only have $10, and then tell both Alice and Bob that I paid $10 to them, who will rightfully own the $10? Some sort of clock/timestamp is needed, in order to determine who received the payment first, ...
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