8

There are multiple definitions of the term "double spending" at play here. First, there is the actual definition of double spending: to spend the same money multiple times. A simple example of this is the coin on a string in a vending machine. You put tie a string to a coin, when you put the coin in the machine, it thinks you paid, you get whatever you want ...


4

Is verification of blockchain computationally cheaper than recreating it? Yes, far easier How do you verify the blockchain integrity? Don't you also have to recalculate all the values to see whether they are valid? No. The miner has to find a value for parts of the block they can choose a value for, such that a hash of the block has a certain number of ...


3

How can they list the unspent transactions and the current amount of an address which "is not in their wallet"? Block explorer sites maintain a separate database of information which is built by continuously scanning the Bitcoin blockchain. If block explorer sites see a standard locking script in the outputs of the transactions, they scrape the addresses ...


3

The difficulty is not constantly increasing. It is increasing in response to the hashrate going up. If the hashrate would be going down instead, the difficulty would automatically go down as well. The goal of the difficulty adjustment algorithm is to keep the average time per block at 10 minutes. If in response to dwindling fees and/or subsidy, mining ...


3

The reason that is often stated is that you would have to re-calculate all the headers with all the hash values of the whole chain which is practically un-doable. It's not the mere recalculation of new headers: miners currently create about 8×10^19 block candidates every second. However, at current difficulty levels, it takes about 4.8×10^22 block ...


3

It's a best effort guess made by blockchain.com, has little relevance, is not particularly accurate, and should not be used for any meaningful analysis. It has no impact on the transaction, and is not part of the Bitcoin protocol. It is somewhat accurate for very simple transactions, but breaks down for larger ones, and ones that utilize more recent anti-...


2

The transaction that you submitted and the transaction that was malleated in-flight or by a miner are both legitimate (valid) transactions. Transaction malleability means that a valid transaction can be modified in-flight, without invalidating it and without access to the relevant private keys. Even if changing the components of the transaction doesn't make ...


2

By definition a node's idea of the blockchain is among all valid versions of history the one with the most total proof of work. Because chains are required to be valid, it is not possible to have a block in there that violates consensus rules. It doesn't matter what miners do; full nodes will still ignore the block entirely, as if it was never created.


2

There are no real rules, per se, just various optimizations. ASICs are fast. They can burn through the entire 2^32 possible nonces for a given block in seconds, which requires miners to use the extra nonce field in the coinbase transaction to generate a new block header (since altering the coinbase transaction changes the merkle root) and try again. This ...


1

I believe you have the same problem reported in the link bellow: https://askubuntu.com/a/490839 Just try to install autoconf. The autoreconf come with it: sudo apt-get install autoconf


1

Assuming two miners have a (1/x) chance of finding a block over some time period, is the probability of both miners finding a block within that period simply (1/x^2)? More generally, would n miners with equal hash rates have a (1/x^n) chance of all finding blocks within some time period of each other? I believe these are both correct assuming the ...


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