Questions tagged [difficulty]

This tag should be used for questions regarding difficulty which encodes the likelihood of one hash to succeed at mining a block. Indirectly, it is a measure of the total hashing power of all miners for a given cryptocurrency.

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57
votes
3answers
31k views

How is difficulty calculated?

Can anyone explain me in the plain English how difficulty is calculated. I have a very approximate understanding that it is calculated based on the amount of hash power in all the bitcoin community ...
52
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4answers
30k views

What keeps the average block time at 10 minutes?

I've been told "the network" sets the difficulty level such that there will be one new block mined every ten minutes. I imagine the rich would instead prefer to keep difficulty as high as possible to ...
44
votes
8answers
16k views

Can bitcoin exist without miners?

In the past year only, the bitcoin mining difficulty has increased fivefold. If in the coming years the difficulty increases so much that mining is no longer profitable (i.e. consumes more power than ...
31
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6answers
123k views

Do these new ASIC miners really pay for themselves in 5 days?

The Bitforce 50GH/s miner costs $2,500 today, and according to the following calculation it would mine enough coins in about 5 days to pay for itself. I am sure I am missing something here. Why would ...
23
votes
1answer
13k views

How does the Kimoto Gravity Well regulate difficulty?

Maxcoin will use the Kimoto Gravity Well (KGW) to regulate the difficulty. From what I could find about the KGW, it retargets after every block and adjusts very quickly, e.g. when multipools add and ...
22
votes
2answers
11k views

What is “difficulty” and how it relates to “target”?

I don't understand what "difficulty" means and how it really relates to "target". I understand what "target" is - it tells the miners, how small the resulting hash should be. (Basically, how many ...
19
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3answers
64k views

What does the mining difficulty number really mean?

I'm new to bitcoin; please bear with me. I'm looking into mining, how it works, and how to get started. I see a "mining difficulty" from many sources and list a 3 billion something number without ...
18
votes
1answer
13k views

Relationship between Hash-Rate and Difficulty

What is the algebraic relationship between Total Network Hash-Rate and Difficulty?
18
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4answers
43k views

Can casual people still mine for bitcoins, now that the difficulty is much higher than it was?

Can casual people still mine for bitcoins? As of October 2012, the difficulty seems very high, being over 3,000,000. I've seen a ad for bitcoins, and watched the video. It said I could mine for them ...
16
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3answers
7k views

How to calculate new “bits” value?

Every 2016 blocks one needs to calculate new bits value. What is the formula to calculate it?
15
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6answers
27k views

Why can't they use super computers to mine all the bitcoins?

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 ...
15
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2answers
2k views

What happens if hash rate decreases rapidly?

Since difficulty is only adjusted every 2016 blocks, what would happen if hash rate was to decrease rapidly? Wouldn't this cause blocks to be created less frequently and also making the time until ...
14
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4answers
4k views

Is there empirical data about a relationship between bitcoin price and difficulty?

There have been claims that Bitcoin price and difficulty correspond. Is there empirical data to support or refute this?
14
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2answers
2k views

How many Integer Operations on a GPU are necessary for one Hash?

I thought it was the ALU OPs like here: https://bitcointalk.org/index.php?topic=7964.0 ArtForz speaks of much higher values, though: https://bitcointalk.org/index.php?topic=4689.msg68933#msg68933 ...
12
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2answers
725 views

Is it possible for the network to stop finding valid blocks?

The hashing problem is by design computationally hard, because SHA-256 hashes are for all intents and purposes random strings with no direct link to their inputs, and there's no (known) way to ...
10
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2answers
2k views

Is there a maximum factor by which difficulty can change?

I seem to recall, long ago, being told that difficulty couldn't change more than a certain amount at each retarget, but I can't seem to find what that factor is (or even confirmation that such a ...
10
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4answers
823 views

What is the ecological effect of increased work for the Bitcoin chain?

As more users use Bitcoin and "forced work" difficulty increases what effect does this have ecologically? It is a silly question I know. I'm just comparing let's say value or effect of using ...
9
votes
8answers
3k views

Can more than 1 block be solved per 10 mins on average (LONG TERM)?

I am wondering whether it is possible for a supercomputer to find the next 1000 blocks in a very short amount of time. Hypothetically, if a government agency concentrated a supercomputer on hashing, ...
9
votes
4answers
2k views

Why invest in mining hardware if the difficulty continues to climb at an exponential rate?

From the FAQ : Creating a block is a proof of work with a difficulty that varies with the overall strength of the network. So with these purty graphs there is a continuous exponential trend in ...
9
votes
1answer
1k views

Reduce difficulty on testnet-in-a-box?

I'm doing some testing and often find myself needing to generate 6 blocks quickly to confirm some tx. Each block takes a few minutes to generate on my macbook so this slows things down considerably. ...
8
votes
2answers
13k views

How many zeroes does the current target have? [duplicate]

I'm trying to get my head around the difficulty setting of Bitcoin. How can I calculate how many zeros the target string needs to start with?
8
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1answer
268 views

Why is target stored in the block at all?

Currently, target is stored in each block. Why is that? Why it is not simply computed by each client based on the previous timestamps from previous blocks? Why it has to be stored within the block? ...
8
votes
5answers
9k views

Will expensive mining equipement have any worth in the future?

With more and more people picking up advanced ASIC miners, the difficulty is going up while the remaining coins are going down. If miners continue joining at this or a faster rate, the limit might be ...
7
votes
1answer
11k views

Calculating average number of hashes tried before hitting a valid block

I'm toying with the idea of starting to mine, and was wondering how to calculate how many hashes on average must be tried before one will "hit" a valid block? I'm talking about a single user (not a ...
7
votes
1answer
2k views

Why does Bitcoin not have faster downward difficulty adjustments?

The BCash fork seems to have correctly anticipated the need to adjust difficulty downwards in the case of very slow blocks. This means it's much less likely for the chain to be orphaned when it was ...
7
votes
1answer
1k views

Where exactly is the “off-by-one” difficulty bug?

I read through How is difficulty calculated? and want to understand where the "off-by-one" bug is in calculating difficulty. Here is a Matlab snipet I wrote to calculate difficulty. What are the ...
7
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3answers
19k views

How does a difficulty increase affect a miner's income?

At the time I write this, there are a lot of people getting into Bitcoin mining for the first time. Many buy ASIC hardware and are later surprised that their mining income suddenly drops due to a ...
7
votes
1answer
358 views

How does one know they solved a block?

Having the difficulty (either in the "bits" form, big integer form, or human-readable format) and a given block hash, how does one know if they solved that block? What is the formula or algorithm for ...
6
votes
1answer
4k views

How is a block header hash compared to the target (bits)?

I'm trying to wrap my head around the mining process by doing a small example of block hashing. According to the Wiki entry about difficulty, the target for a block hash can be read from the "bits" ...
6
votes
1answer
439 views

Why was the maximum target set to 0xffff0000000…?

Is there any specific reason why the initial target was set to this: 00000000ffff0000000000000000000000000000000000000000000000000000 Why not the maximum value for a 256 bit number: ...
6
votes
2answers
755 views

Is there a uniform measure of “difficulty”, that when multiplied by price, will give “profitability of one hour of mining”?

I recently open Bitcoin Pie, a site that compares crypto-currencies. Given the exchange rate in BTC, I would like to add another column that tells "relative mining profitability", regardless of the ...
6
votes
1answer
1k views

How can I find the “real” difficulty on testnet?

As is well known, testnet has a "20-minute rule": if no block is found within 20 minutes, the mining difficulty drops to 1 until a block is found. From some experimentation, it appears that bitcoind'...
5
votes
2answers
1k views

Why is it harder to compute nonce for a hash with a certain number zero prefixes than it is for any other hash?

Based on my rudimentary understanding of Bitcoins and altcoins, network difficulty is adjusted by asking the network to target a hash smaller than a specific number, which translates to calculating ...
5
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4answers
6k views

When will next halving events occur?

I've read in some places that the next halving event will be on 2016. How can this be estimated?
5
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2answers
2k views

Why would a miner mine with a difficulty other than 'the' difficulty?

Why would a miner mine with a difficulty other than the network difficulty? Both of these questions describe miners mining in such a way. What's the benefit of this? What even does it mean?
5
votes
1answer
5k views

How is the target section of a block header calculated?

I've been poking around https://en.bitcoin.it/wiki/Target and I've found the current target, but I can't seem to find how it's generated. It's supposedly generated when the difficulty is adjusted, as ...
5
votes
3answers
540 views

Bitcoin inflation in 9/12 doesn't seem to have been corrected. Why not and will it be fixed?

I'm looking at the Total Bitcoins in Circulation graph and don't understand why there is a spike of coins being generated in Sept '12. What caused this to happen? Also, since there is a fixed number ...
5
votes
2answers
14k views

How to select minimum difficulty when mining with Slush Pool

I am mining on a single Antminer S9 with Slush Pool. There is a setting called "minimum difficulty": When I read their manual, item #8 states The pool automatically assigns difficulty that ...
5
votes
2answers
2k views

How does solving reduced difficulty hashes contribute to solving a block? [duplicate]

In pool mining, it's my understanding that miners solve a reduced difficulty hash which proves that work is being done and also simultaneously helps solve a block. How is this computationally ...
5
votes
1answer
14k views

When will the Bitcoin Cash difficulty adjust next?

Bitcoin Cash adjusts its difficulty downwards if there is, roughly speaking, a 12 hour gap between blocks. At least that's my understanding. Difficulty has dropped to about a quarter of what it was ...
5
votes
3answers
6k views

Why is mining difficulty increasing?

I have heard in many places that mining difficulty is increasing, meaning that the hardware used to mine new coins will need to be more and more powerful as time goes on. What is pushing mining ...
5
votes
3answers
283 views

Bitcoin value vs. Supercomputing

What protects the stability of Bitcoin's value if supercomputers or some other technological breakthrough allows them to be mined at rates we have not anticipated?
5
votes
2answers
719 views

Does difficulty ever stop increasing?

I know we don't have to worry about this for a very long time, but... One argument against Bitcoin, and really, digital currencies as a whole, is that, in order to time blocks with reasonable ...
5
votes
1answer
231 views

If ASIC based machines can run at 14TH/s, why isn't the answer found almost immediately?

As far I understand correctly, the objective is to find a nonce which creates a hash with the specified difficulty. The current difficulty being around 1.4 trillion. If that is so, why doesn't a ...
5
votes
1answer
477 views

How does mining process takes Approximately 10 minutes?

I don't think that I fully understood the "difficulty" topic in blockchain, and therefore I don't understand how mining process takes close to 10 minutes. If I have "Target" value (some hash value, ...
5
votes
1answer
358 views

How is nbits calculated?

When generating a new block, how is the nbits field in block header calculated? Is nbits calculated for every new block like: nbits=nbits of last block * (timstamp of lastblock-timestamp of (...
5
votes
1answer
850 views

Creating Mining Competition on regtest

As we know , Bitcoin core-Regtest is used to set up our own blockchain starting from Genesis Block. I have created Two nodes on my localhost running on different ports (I am using Windows 8.1). They ...
5
votes
3answers
56k views

How many shares need to be mined before a block is released?

How many shares need to be processed on average before a block is found? I know that "luck" can be a huge factor which is why it's not quite as simple as that. I ask because I'm starting my own pool ...
4
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2answers
1k views

how exactly was the original coefficient for difficulty determined?

I'm assuming difficulty has a "target" of 10 minutes because the coefficient satoshi chose becomes multiplied by a variable to help the network remain in proportion. IE, if the network hashrate is 2x ...
4
votes
2answers
275 views

Why aren't block hashes used directly as scores for difficulty purposes?

Why does Bitcoin apply a difficulty function to block hashes and then use the output of this function to add up and determine the "longest" chain? Why not just e.g. add together all block hashes (as ...