A hash is a mathematically reproducible but irreversible process which takes one value as an input and predictably produces a derived value as an output. Hashing is central to Bitcoin mining as well as the generation of Bitcoin addresses.

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Shabal256 code explanation

Can anyone please explain the code below with comments? What are pbegin & pend ? What is ( I believe it is data, where it comes from ?): (pbegin == pend ? pblank : static_cast<const ...
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60 views

bitcoin address to Hash 160 public key : not consistantly reversible?

When I use blockchain.info tools or bitcointoolkit.info tools to convert an address, such as 1MCNpVGDY7BGjJyWZL5FJZiaVkQEiuxy8H to a hash 160 public key : I get ...
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35 views

Is Quark as secure as SHA 256?

I'm trying to make certain I'm understanding the purpose behind the Quark algorithm. There are lots of devices that need secure algorithms but have severe power and processing constraints such as ...
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2answers
110 views

Visualize Bitcoin Hashing

According to https://en.bitcoin.it/wiki/Hash, BitCoin uses the SHA-256 hash algorithm to generate verifiably "random" numbers in a way that requires a predictable amount of CPU effort. ...
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2answers
68 views

Work distribution in a mining pool

How is work distributed among members of a pool? Regarding the block hashing algorithm and valid hashes of a new node, how is the set of solutions for nonces "distributed" among miners?Is a nonce, ...
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56 views

What sort of calculations do the miners have your computer do? [duplicate]

I recently heard of a new cryptocurrency (or maybe it's not new and I'm just out of the loop) called Gridcoin which uses your GPU/CPU/ASIC to do research calculations rather than "meaningless" ...
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54 views

What is a midstate? How does using a midstate speed up hashing?

This defines "midstate" as the "precomputed hash state after hashing the first half of the data." I've heard "midstate" used in the context of speeding up hashing. How does using a midstate speed up ...
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2answers
214 views

Does every nonce really have an equal chance of winning?

I set out to test the claim: "Every nonce has an equal chance of winning." Time Evolution So, I plotted, with gnuplot, the nonce values vs. hashes for all the valid blocks in the blockchain:(Also, ...
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377 views

What mining performance can we roughly expect from the Intel SHA extensions of the upcoming Skylake processor architecture?

Intel is scheduled to release their new x86 SkyLake microarchitecture in Q3 2015. Among other interesting features, it will introduce SHA extensions that will allow hardware acceleration of the Secure ...
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136 views

Are Bitcoin ASICs Optimized for Fixed Length Messages?

Bitcoin block headers are 80 bytes. int32_t nVersion; // 4 bytes uint256 hashPrevBlock; // 32 bytes uint256 hashMerkleRoot; // 32 bytes uint32_t nTime; // 4 bytes uint32_t nBits; ...
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3answers
382 views

How do cloud hashing companies profit? (leasing hashing power)

I think I'm missing something. There are a bunch of cloud hashing companies that lease hashing power. Let's take cointellect for example. They have contracts from 10 days to 24 months. If I buy a 10 ...
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2answers
176 views

How safe is bitcoin with regard to a random address generation attack? [duplicate]

Imagine an attacker implementing something like the following pseudocode on the fastest ASIC farm money can buy: attack(blockchain, my_address) addresses = ...
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265 views

How can I mine ALT SHA-256 coins using a Bitmain S4?

The bitmain S4 does 2TH/s out of the box with no overclocking. For many alt SHA-256 coins, this can be 10% - 50% of the entire network hashing power, which would allow us to gain alt coins quickly, ...
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0answers
47 views

How do satoshidice's draws work? (HMAC hashes) [duplicate]

I am trying to understand how does a satoshidice draw work. As far as i have understood satoshidice generates daily two public hashes: HMAC hash (H from here on) Position hash (P grom here on) ...
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2answers
393 views

What does it mean for a cryptocurrency to be ASIC-resistant?

I guess the question I'm asking here is what does it take for an altcoin to be ASIC-resistant? What does it need to have?
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1answer
41 views

Proof of work - does the equipment matter?

It technically doesn’t matter whether I am using a super computer or a laptop to do the proof of work, it’s simply that with a super computer I can go through the attempts much faster, which means I ...
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2answers
108 views

SHA256 * 2 on header - what am I doing wrong?

I've been experimenting with the php code here: https://en.bitcoin.it/wiki/Block_hashing_algorithm (after correcting the small bug of $x=; to $x=""; ) With these blocks 0 and 125552 (for example) it ...
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248 views

How does a proof of work limit of `~uint256(0) >> 20` translate into a difficulty of `1 / 2^12`?

In the Litecoin source it is written: static CBigNum bnProofOfWorkLimit(~uint256(0) >> 20); // Litecoin: starting difficulty is 1 / 2^12 How does that compute? ~uint256(0) >> 20 is ...
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2answers
124 views

What is the average number of hashes it takes to mine bitcoins?

I'm just curious about this. I'm not sure if the length of zeros in the hash result is directly proportional to the probability, or how to calculate this.
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mining pcie 16x and 1x together caused rejects

I have 5 msi radeon R9 290 cards and this board https://www.asus.com/Motherboards/Z87PLUS/specifications/ . With 3 pcie 16x everything runs smooth but, as soon as I add the first 1x into the equation, ...
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1k views

BFGminer can't find my NanoFury on Raspberry Pi

Related: BFGminer can't find my NanoFury! Posted on the RPi Exchange as well http://raspberrypi.stackexchange.com/questions/14753/bfgminer-cant-find-my-nanofury-on-raspberry-pi Forums: ...
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1answer
117 views

How accurate should pool estimation of hashing speed be?

I'm playing around with a few USB miners, and am running 4 of them for a total of 4.6 GH/s. My BTCGuild dashboard estimation is all over the place, sometimes 1 GH/s, sometimes as high as 3.8 GH/s. ...
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2answers
61 views

Required number of bits in nonce [duplicate]

Is there a formal proof that with N bits to iterate in the nonce of the block, a hash satisfying proof of work will be ever found? How large that N (number of bits in the nonce) should be to satisfy ...
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1answer
99 views

Can mining puzzles be made socially valuable? [duplicate]

Bitcoin miners work to solve a random puzzle as "proof of work". A huge amount of raw computing power is going into finding the solution to these puzzles, yet the actual solution to the puzzle serves ...
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149 views

Would it be possible to have an ARM hashing based Cryptocurrency?

This was something that popped into my mind while I was thinking about CPU Only Alt-coins. Would it be possible to have an ARM-based coin? That is, a coin that could only be mined on ARM devices ...
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1k views

Effect of internet connection speed on solo mining [duplicate]

I have a set of PCs hasing at 100 kH/s and currently the network difficulty is 2674.36329706. My power usage is 200 W, and as per ...
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3answers
201 views

Does a miner (or mining pool) who has 10x as much hashing power have 10x the odds of mining a block?

I heard somewhere that joining a mining pool logarithmically increases your odds of mining a block.. is that for some reason true? Or was it someone who didn't know what they were talking about and ...
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2answers
490 views

Can you help with Bitcoin block hashing algorithm ( PHP, C, Python, Javascript)? [closed]

can you help with Bitcoin block hashing algorithm ( PHP, C, Python, Javascript) ? I was working really hard to write block hashing algorithm in plain Javascript. Unfortunately the developed ...
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9k views

What is the conversion then for MH/s to GH/s and so on [duplicate]

I've seen this answer and maybe I'm just tired What is the difference between KH/s MH/s GH/s? 1 kH/s is 1,000 hashes per second (sometimes mistakenly written KH/s). 1 MH/s is 1,000,000 ...
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1answer
139 views

Block Hashing Data

Guys I have a few points that are not clear for me. 1) In the link below it says there are some fields we have to combine and hash. However when I get a work by saying getwork from a pool. What I get ...
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379 views

What is the approximate hashrate of a human?

Which and how much mathematical operations are required for the blockheader-to-blockhash operation and how fast would a human be able to calculate a single hash? EDIT: For simplicity, I think it's a ...
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4answers
1k views

Why can't we design a bitcoin that does useful work? [duplicate]

The bitcoin network, including every miner, is the biggest computing project that humanity has created. Thus I ask: why, instead of using it to generate useless data, don't we use it to generate ...
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2answers
5k views

What is the relationship between hash rate and accepted shares?

Specifically this question is about Litecoin, but I suspect the answer would apply to both. Say you have a rig mining at 700Kh/s (LTC). It seems that you get, more or less, a one or a few accepted ...
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2answers
115 views

How large can the bitcoin salt value be?

To mine bitcoin I believe that you take the input and add a salt number to that then run the hashing algorithm to find a suitable output, but how large can the salt be, couldn't I just take the ...
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4answers
5k views

BFGminer can't find my NanoFury!

I recently purchased a Nanofury ASIC unit. I tried running it on my Linux system, as I just let the computer sit and run. I couldn't get it to work on Linux, so I decided to give it a try on Windows = ...
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2answers
2k views

When mining with 2 computers, do I need to use 2 separate wallets addresses?

I understand that each miner is working on a different block. Correct me if I'm wrong but this is because the first transaction in a block basically contains my wallet address so I can receive the ...
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1answer
121 views

Can an old block be inserted into the blockchain?

I've been shown how network time is enforced, but I'm still having trouble understanding how a false old block cannot be inserted into the blockchain with the entire chain remined or how a powerful ...
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138 views

The bitcoin address space seems to be closer to 2^40, not 2^160

The Base58 Encoding of a public key hash outputs: "A set of 58 alphanumeric symbols consisting of easily distinguished uppercase and lowercase letters (0OIl are not used)" This set is a fixed string ...
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1answer
129 views

Are transactions still tamper-proof if blocks are hashed without nonces?

If an alt were to forgo difficulty and timed release of new supply by removing the nonce from blocks therefore the whole difficulty/target system, is hashing without nonces still providing the same ...
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1answer
339 views

Mining a primecoin based currency (datacoin). How do I find out how much hash power im doing?

How do I find out how much hashing power am I providing to the network? What is the command to find it out? Currently I see this: http://prntscr.com/2cd3zo when I run: watch 'datacoind ...
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1answer
147 views

Why are blocks hashed?

Am I correct that addresses are hashed to compress a huge text-represented coprime into something of manageable size? Am I also correct that transactions are hashed for the same reason and also ...
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1answer
14k views

How to work out my hardware's hashrate power

Using my existing hardware, I want to work out which altcoin is still profitable to mine. I have found this link: http://dustcoin.com/mining But don't know which values to enter into the boxes at ...
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4answers
4k views

Alternative Cloud Hashing sites to Cex.io [closed]

I am really impressed with Cex.io and their whole concept of trading Ghs for Bitcoin as well as cloud mining which I find to be novel and interesting. Are there any other sites like that? I know ...
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2answers
8k views

Will the 3TH KNC Neptune Miner still be profitable in 2014?

I am seriously considering making an investment and buying a 3TH miner. The problem is whether they will still be profitable by the time they arrive... At today's has rate calculation of 707,408,283 ...
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1answer
2k views

Quarkcoin money supply and hashing

If the money supply of Quarkcoin is 257 million QRK, what will be the incentive for miners to mine 1 million coins a year? What does it mean for the currency if almost nobody is mining it? Also why ...
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2answers
819 views

How do signatures work?

Just curious, if I send a transaction from one address to another, how do they verify it without knowing my private key?
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1answer
104 views

Is the idea of a “honey hole” such as in gold mining, present in bitcoin mining?

I understand the output of the SHA-256 hashing function is a random number between 0 and 2^256. Does the randomness of this output imply that there cannot be a, so to say, honey hole in the hashing. ...
2
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1answer
312 views

Cheating ASICs and Mining Software

I've noticed the recently solved block hashes have started with a number of zeros (8 last time I checked). Couldn't we just tell our mining hardware/software to assume the first few digits are in fact ...
5
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1answer
8k views

What do `minerd`s feedback messages (LONGPOLL, yay, boo) mean?

I have been testing a script that essentially runs (incomplete command shown here!): minerd --algo scrypt -s 45 --retry-pause 5 --threads $threads --url ... Among the feedback messages, while minerd ...
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982 views

Bitcoin block hashing algorithm. nonce

Referencing the Bitcoin wiki, what is the auhoritative source for providing a hash of the previous block? Or do miners keep listening to latest blocks? How is hash of the Merkle root generated? Can ...