46
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Why doesn't Bitcoin migrate to proof-of-stake?
Proof of Stake is basically a case of having your cake and eating it, too.
PoW is a simple work-around to a coordination problem that was previously thought to be unsolvable. It sort of "cheats&...
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21
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Why doesn't Bitcoin migrate to proof-of-stake?
I think there are at least four reasons:
The miners are stakeholders in the bitcoin ecosystem. Mining solves a problem for them. Taking away PoW mining would make bitcoin no longer work for one of ...
- 51.7k
20
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How does proof of work inspire trust when the work is just guessing?
Forget PoW for a second: lets instead imagine that you have a box, and you've placed a lock on it, in order to secure its contents.
Now, if someone asks you how secure the contents are, then the ...
- 18.4k
15
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Why doesn't Bitcoin's PoW algorithm use a chain of lower-difficulty hashes?
That would violate the progress-free property of mining, which is very desirable.
If miners have to construct multiple PoWs per block, that means they (private) accumulate points, and the first one to ...
- 110k
14
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Why do we need Proof of Work in bitcoin?
Proof of Work (PoW) basically makes sure that miners don’t cheat.
There is no way to trust that everyone in the network is honest, so there has to be some way to prevent miners from creating new ...
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14
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Why doesn't Bitcoin migrate to proof-of-stake?
I think there are some very convincing theoretical arguments to be made, but there is also just a very practical consideration:
Right now, a very large portion of BTC is being held in the cold ...
- 18.4k
12
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Accepted
Why do we need Proof of Work in bitcoin?
Imagine I have 1 bitcoin. And imagine I can form a transaction to send that bitcoin to Alice or I can form a transaction to send that bitcoin to Charlie.
Now, what stops me from forming both ...
- 51.7k
11
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Does proof-of-work contribute directly to prevent double-spending?
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 ...
- 72.1k
10
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51% attack and rewriting to the latest checkpoint
As long as both competing chain-tips are adhering to the same rules, the chain with the most aggregate difficulty ("heavier") will win, regardless of height. Nodes performing the initial sync would ...
- 77.8k
10
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What prevents similar time-warp attacks in Bitcoin as happened to Verge?
Nothing directly prevents it in Bitcoin, and indeed the attack has been demonstrated on testnet3 many times---it's the primary reason that testnet3 currently has almost three times as many blocks as ...
- 12.2k
10
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Is proof-of-work required in Bitcoin?
Proof of work does not create trust. It creates incentive.
Miners are paid if their block is eventually part of the main version of history ("blockchain") that the network accepts. They must ...
- 110k
10
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Why is the winner of Pow different everytime?
Because each miner may select the transactions (and the order in which they are included) in each block. Also, they do not all start on the same exact nonce, in fact they are changing more than just ...
- 7,428
10
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Beginner's question: Why must proof-of-work be useless?
In addition to the technical factors mentioned by MCCCS, it's important to consider economical factors as well.
If the problem being solved has value outside of the Bitcoin network, it allows miners ...
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8
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Chain with most proof of work - hash target or block header hash?
It's the sum of difficulty targets, not the individual difficulty scores. Therefore, two blocks at the same blockchain height are always the same cumulative difficulty¹.
If it were individual ...
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8
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Is Bitcoin PoW actually SHA256 + Merkle generation? Or have I misunderstood coinbase/append?
You are correct that effectively Bitcoin PoW involves computing the Merkle root every now and then in addition to the hash grinding.
However, this is negligable. Even ignoring nTime rolling, the ...
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8
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How does a blockchain relying on PoW verify that a hash is computed using an algorithm and not made up by a human?
A Hash Function maps "data of arbitrary size to fixed-size values". As an incredibly simple hash, consider a function only works on numbers and simply returns the last 3 (decimal) digits (ie....
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7
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How does Proof of Burn work?
Attention: Ambiguity!
Note that the term (or abbreviation) "PoB" can be used differently. For example, some cryptocurrencies allow users to get some of their coins for provably burning money in ...
- 3,244
7
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How does a miner get selected in Proof Of Stake?
The minting algorithm for staking is different for various coins; for example, it is different in BlackCoin from Cardano.
There are several approaches to staking, but most of them are susceptible to "...
- 1,012
7
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Why don't the miners just take profit from our coins and make the coin worthless?
Because miners do not actually own/ or have access to the bitcoins which are being spent in a transaction.
They simply choose a number of transactions which have valid signatures, and put them ...
- 1,081
7
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In what sense does the security model of proof-of-stake require users to "log on to the internet every few months"
What Vitalik is talking about is the Slasher algorithm that he designed which punishes the block signer if he attempts to create a fork in the blockchain. However the way that slasher works is that ...
- 72.1k
7
votes
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How does scrypt pow work?
It's the same: the proof-of-work is that the scrypt hash of the block header must start with a certain number of zeros (or, more precisely, be numerically less than a certain target value). However, ...
- 23.1k
7
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PoW 51% attack vs. BFT 1/3 attack?
So from what I understand, Bitcoin's PoW is prone to 51% attack, but as a distributed system it is also prone to BFT's 1/3 attack right?
No. Bitcoin is not a "consensus system" by any of the ...
- 7,727
7
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What hash algorithm is used in Bitcoin Cash?
BCH and BSV both use SHA256 as their POW algorithm, as does Bitcoin (BTC).
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7
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How does a blockchain relying on PoW verify that a hash is computed using an algorithm and not made up by a human?
Because
Everyone can quickly use the transaction data to re-calculate the hash and check that it matches and is less than the target value.
Computing the hash is not what takes time, it is altering ...
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7
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Would Bitcoin still work without a target difficulty?
It's not trivial a) to agree on the time in a distributed system, especially how much time has passed between two events, b) to establish when exactly a block candidate was found. Further, when a node ...
- 77.8k
7
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Why doesn't Bitcoin's PoW algorithm use a chain of lower-difficulty hashes?
As is usually the case in Bitcoin, the reason the PoW algorithm works the way it does is because it was the best Satoshi could come up with, and now we're stuck with it unless we do a hard fork.
...
- 10.4k
6
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Byzantine Fault Tolerance Threshold of Bitcoin: 1/2 or 1/3? (Edited)
It depends on what you're actually asking. Bitcoin doesn't exist within the normal model of BFT consensus so in one sense the answer is mu.
Under conventional assumptions Bitcoin will converge on a ...
- 7,727
6
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Proof of work - lottery approach
There's a lot going, but I'll do my best.
QUESTION: Can the bitcoin network randomly select a subset of the existing nodes, for each block, who then compete to solve the hash?
Selecting a subset ...
6
votes
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What would happen if miners refused halving
What if after this phase the first miner or more than 51% of them decide to keep the current production rate ? Do their block will be refused like if they had produced a wrong block ?
Exactly. This ...
- 18.4k
6
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How much more energy efficient is PoS (proof of stake) than PoW (proof of work)? Are there any figures on this?
When providing an equivalent amount of security, I don't believe PoS can be more efficient than PoW. I do understand how it may appear this way on the surface, but I think deeper consideration shows ...
- 18.4k
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