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I have very limited knowledge of bitcoin, but, I hope you don't mind my asking this question:

As I understand it, "mining bitcoin" requires "significant" computational prowess. A lot of dedicated mining rigs have been built out of FPGAs, ASICs and GPUs. But, I have always wondered: would it not be possible to mine ALL the bitcoins if you had access to some of the most powerful computers? So, for argument sake, if the NSA decided to stop snooping upon people and instead decided to, you know, mine bitcoins… would they be able to mine all the bitcoins in just a few hours if they redirected all their super-computational-power towards this one problem: mining bitcoins? Other potential candidates for this game include, but are not limited to: NASA, DoE, etc.

I realize that running a supercomputer to mine bitcoins may NOT be efficient (because a super computer consumes too much power, costs a lot of money, etc) but for a govt agency all that money comes from taxes so ...

Now, hypothetically, could "they" mine all the bitcoins in a few hours, or even in a few minutes if they redirected all their super-computational-power towards this one problem: mining bitcoins?

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    You might be interested to know that, while the techniques used to measure this are less-than-accurate, the Bitcoin network has been estimated to be about 6 to 7 times more powerful than the entire combined power of the top 500 supercomputers in the world. cnnmoneytech.tumblr.com/post/51098009327/… Maybe not a 100% accurate measurement, but when you win by a factor of 6 the error bars would have to be pretty large to falsify that statement... – David Perry Jun 30 '14 at 20:43
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A supercomputer is way slower than mining with ASICs. A supercomputer only has much CPU power, not even GPU power and ASICs are way more powerfull than GPUs. ASICs represent the hashing algorithm as hardware which means they can't do anything else, that's why they are so fast.

At http://bitcoinwatch.com/ you can see the current network hashrate in PetaFLOPS, which is 1534782.24 at the moment. Currently the fastes Supercomputer Tianhe-2 has 33.86 petaFLOPS.

but for a govt agency all that money comes from taxes so ...

If they would use all the money to buy ASICs and start mining bitcoins, it still would not be enough because of the difficulty factor. But they would be able to get a lot of blocks because the difficulty only changes every 2016 blocks.

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    Maybe stupid question: why are we even building supercomputers if ASICs are better? – Mathias711 Jun 30 '14 at 17:52
  • ASICs are the hashing algorithm formed into hardware, so they cant do anything else while server can do what ever they are used for ;) – Dennis Kriechel Jun 30 '14 at 17:54
  • Good. My logic was working this time. – Mathias711 Jun 30 '14 at 17:57
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    That's actually a really important part of the argument: ASICs are only made to do one thing, so it's not even a fair comparison. A specialized tool will usually win out over a general-purpose one for the one task it's designed to complete. We're comparing a rocket car to a Honda Civic here - the rocket car is obviously going to be faster, but you sure wouldn't want to drive it to work... – David Perry Jun 30 '14 at 20:46
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    They cant have enough power by supercomputers because they would need 16k times more power than the currently fastes supercomputer... Even with enough power they cant do it because of the difficulty factor see post. I guess its impossible, at least currently, for them to have 16k Supercomputers which are as powerful as the currently top one. – Dennis Kriechel Jul 1 '14 at 8:34
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There are two reasons why they can't flash mine all bitcoins: Difficulty and specialized hardware.

First, the pace of Bitcoin creation is limited. The protocol defines how difficult it is to find more bitcoins. At normal pace, the difficulty is evaluated and readjusted about every 10-14 days. However, because the difficulty adjustment happens after a fixed number of blocks, the time until readjustment is shorter when blocks are found at a higher rate.
When blocks are discovered quicker than the target 10 minute interval, the protocol requires a readjustment to a higher , which in turn causes the pace to slow down. For a more detailed explanation see: How does the network adjust the rate at which the coins are created?

Mining in Bitcoin is done with application specific integrated circuits. ASICs are chips that can only execute one algorithm because it is hardwired into the chip. As these Bitcoin ASICs are single-purpose designed to solve only the calculations required for mining, they are highly optimized to do so. This lack in flexibility allows to increase their efficiency over general purpose hardware immensely, and has caused the hashrate of the Bitcoin network (the total "mining power") to grow about 20,000x (twenty thousand fold) since the first Bitcoin ASICs have shipped. General purpose chips are many magnitudes less efficient at mining, and therefore don't stand a chance at competing.

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Supercomputers are programmable to do anything. ASICs are built from scratch to calculate hash functions only. It is like comparing a human body, that can be trained to demolish a wall using karate, with a wrecking ball.

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No, there is a difficulty argument built into the Bitcoin protocol itself, so the NSA would not be able to mine "all" the Bitcoins.

  • you are right that a single high power unit cant get all blocks at once, but still the supercomputers dont have enough power at all for bitcoin mining – Dennis Kriechel Jun 30 '14 at 19:17
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    @Recall: We can't know that for sure, as the NSA does not publish information about how much compute power it has available. – Jacob Krall Jul 1 '14 at 2:18
  • They cant have enough power by supercomputers because they would need 16k times more power than the currently fastes supercomputer... – Dennis Kriechel Jul 1 '14 at 4:36
  • @JacobKrall ... that's a really good answer. – thatmaheshrs Jul 1 '14 at 8:35
  • why was this answer down-voted and by whom? – thatmaheshrs Jul 4 '14 at 17:35
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The bitcoin network hashrate estimate on bitcoinwatch.com passed 1 exaFLOPS (1,000 petaFLOPS) which is over 8 times the combined speed of the top 500 supercomputers. Bitcoin network does this by using ASICs. Therefore a supercomputer cannot mine al the bitcoins in matter of hours. Even if they could have, they have much better work to do...

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The Bitcoin network self-adjusts for the amount of hashpower available in total. This ensures that it will always take, on average, 10 minutes to mine a single block, regardless of the amount of hashpower on the network.

Basically as the total hashpower on the network goes up, a parameter called bits in the block headers goes down. This means that the amount of effort that miners have to expend to mine a block increases. If the hashpower of the network were to increase by a factor of 10, then the bits value would adjust such that the network would require 10 times more hashpower to mine each block as before. This has already happened many times over the lifespan of Bitcoin - modern ASICs are millions of times more powerful than the CPUs that were originally used to mine Bitcoin blocks. Yet the time to generate a block remains at 10 minutes on average.

So to answer your question, there will never be a computer fast enough to mine all blocks in just a few hours - not even in theory. All Bitcoins will be mined by approximately the year 2140 but not before.

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