3 ms·

I don't understand why mining is so computationaly intensive. Well, I understand that it's used as a way to limit the rate that new coins are introduced, but ar

by pkulak 16y ago

I don't understand why mining is so computationaly intensive. Well, I understand that it's used as a way to limit the rate that new coins are introduced, but are all these mining computers doing anything useful, or are they just wasting electricity?

sgornick 16y ago
Right now the bitcoin network is calculating at about 500 GHash/second. Only 1 hash is needed to process an entire batch of transactions (a block). Well, technically it is 2 SHA hashes that are needed per block. So 499,999,999,998 of the hashes calculated in the next second will be wasted. It gets worse. That is 500 GHash per second. Over the approximately 10 minutes between blocks, only two of those 300,000,000,000,000 hashes that were calculated will actually be used even. Of course, there is a reason for this. Hashing to obtain a relatively unique result is called a "proof of work" and is the method that Bitcoin uses to ensure that the amount of currency issued occurs only at the levels specified in the source code. http://en.bitcoin.it/wiki/Proof_of_work http://en.bitcoin.it/wiki/Proof_of_work So far, that method has been the only one found so far that works as the transaction processing system for a decentralized payment network.
kiba 16y ago
They're doing something useful. 1. They secure the network from attackers and check for double spending attempt. 2. They process transactions.
joelthelion 16y ago
If you can implement a bitcoin clone without the computational load, it will be a revolution. But this is the best we've found so far: it secures the network, records the transactions and does the initial distribution of coins.
mrb 16y ago
Bitcoin needs a problem (any problem) that is computationally difficult to solve in order to be able to offer certain security guarantees. This arbitrary problem was chosen by its designer: For a given target T, find X such as SHA256(SHA256(X)) < T It is correct that in and of itself this computation is useless. But exactly like http://en.wikipedia.org/wiki/Hashcash http://en.wikipedia.org/wiki/Hashcash it is vital for it to be difficult to solve. In fact the whole network adjusts T dynamically to keep up with the fantastic exponential hash rate growth of the network these last 13 months: http://blog.zorinaq.com/?e=49 http://blog.zorinaq.com/?e=49
- tocomment 16y ago
  Could you use rainbow tables to speed this up?
  - mrb 16y ago
    No because parts of X are effectively variable, change all the time, and depend on things not controlled by any single entity (transactions, block chain, etc). Technically X is a block header https://en.bitcoin.it/wiki/Protocol_specification#Block_Headers https://en.bitcoin.it/wiki/Protocol_specification#Block_Head... Miners change the 'nonce' part of X to attempt to satisfy the above equation.
Tichy 16y ago
Put simply: bitcoin mining is a race with hypothetical hackers. A hacker trying to create fake bitcoins would have to create hashes faster than the real bitcoin network.

by pkulak 16y ago

sgornick 16y ago

Right now the bitcoin network is calculating at about 500 GHash/second. Only 1 hash is needed to process an entire batch of transactions (a block). Well, technically it is 2 SHA hashes that are needed per block. So 499,999,999,998 of the hashes calculated in the next second will be wasted. It gets worse. That is 500 GHash per second. Over the approximately 10 minutes between blocks, only two of those 300,000,000,000,000 hashes that were calculated will actually be used even. Of course, there is a reason for this. Hashing to obtain a relatively unique result is called a "proof of work" and is the method that Bitcoin uses to ensure that the amount of currency issued occurs only at the levels specified in the source code. http://en.bitcoin.it/wiki/Proof_of_work http://en.bitcoin.it/wiki/Proof_of_work So far, that method has been the only one found so far that works as the transaction processing system for a decentralized payment network.

kiba 16y ago

They're doing something useful. 1. They secure the network from attackers and check for double spending attempt. 2. They process transactions.

joelthelion 16y ago

If you can implement a bitcoin clone without the computational load, it will be a revolution. But this is the best we've found so far: it secures the network, records the transactions and does the initial distribution of coins.

mrb 16y ago

Bitcoin needs a problem (any problem) that is computationally difficult to solve in order to be able to offer certain security guarantees. This arbitrary problem was chosen by its designer: For a given target T, find X such as SHA256(SHA256(X)) < T It is correct that in and of itself this computation is useless. But exactly like http://en.wikipedia.org/wiki/Hashcash http://en.wikipedia.org/wiki/Hashcash it is vital for it to be difficult to solve. In fact the whole network adjusts T dynamically to keep up with the fantastic exponential hash rate growth of the network these last 13 months: http://blog.zorinaq.com/?e=49 http://blog.zorinaq.com/?e=49

tocomment 16y ago
Could you use rainbow tables to speed this up?
- mrb 16y ago
  No because parts of X are effectively variable, change all the time, and depend on things not controlled by any single entity (transactions, block chain, etc). Technically X is a block header https://en.bitcoin.it/wiki/Protocol_specification#Block_Headers https://en.bitcoin.it/wiki/Protocol_specification#Block_Head... Miners change the 'nonce' part of X to attempt to satisfy the above equation.

Tichy 16y ago

Put simply: bitcoin mining is a race with hypothetical hackers. A hacker trying to create fake bitcoins would have to create hashes faster than the real bitcoin network.