# Questions tagged [algorithms]

Regarding the underlying algorithms related to Bitcoin protocol.

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### SegWit signing algorithm and its improvement

I was reading about Segregated Witness upgrade from the book Mastering Bitcoin by Andreas and there were some questions I have not figured out. I am appreciated to get some of your help! A) There was ...
53 views

### If there was an easy way to check for double spends, will consensus algorithms be needed?

Currently, checking for double spends is very computationally expensive, so consensus algorithms, like POW, were put in place to more easily prevent double spends among other things. Ignoring the fact ...
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### What exactly determines how long it takes a given miner to mine 1 btc block? (not talking about hashrate) [duplicate]

So given the number of miners out there working on doing the same thing and that 1 block is mined every 10 minutes, it would appear at face value that only those with the highest hashrates would ever ...
61 views

### Why is SHA-256 mining secure?

My understanding is the when you are mining bitcoin you are looking for a string, or maybe a binary number (a) such that if you 'add' a to the block (b) you get a number (c) whose hash begins with a ...
578 views

### In Bitcoin, what happens if there is no viable nonce?

I'm assuming SHA is perfectly uniform. In bitcoin, there are \$2^{32}\$ possible inputs per block, which are mapped to \$2^{256}\$ possible outputs. So there is a \$1/2^{224}\$ chance that any randomly ...
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1 vote
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### Why do we need 2F prepare certificates instead of just F+1 in PBFT?

I started reading PBFT and I could not understand: why do we need 2F prepare certificates? The client needs only F + 1 replies, not 2F, so why can't the same rule be applicable in the prepare phase of ...
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1 vote
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### What is the optimal way to increment extranonce?

I'm trying to learn how to block headers are created and an efficient way of doing so. Given a list .of transactions, can I change the extranonce without having to rehash the entire list? EDIT: To ...
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1 vote
452 views

### Is verification of a blockchain computationally cheaper than recreating it?

One of the advantages of cryptocurrencies like Bitcoin that is often repeated is how hard it should be to manipulate past transactions. The reason that is often stated is that you would have to re-...
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### What are the differences between Bitcoin and Libra?

Recently, Facebook announced to launch a crypto currency called "Libra". Libra is managed by associations under the name "Libra Association", see https://libra.org/en-US/association/. What are the ...
1k views

### What is the difference between BFT and PBFT

What are the differences between BFT and PBFT? I want to know the difference between these two concepts. If there is any improvement in the BFT's limitations, let me know. Please answer. Thank you.
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### what happens when their is a bicoin algorithm half? [duplicate]

I saw in an article something about a bitcoin algorithm half in 2020, what exactly is this, I have tried looking this up but I couldn't find anything that told me what it was only this.
128 views

### Why haven't a large number of cryptocurrencies copied Primecoin's mining algorithm? [closed]

According to my understanding, generating an ever-growing list of prime numbers benefits mathematics and society in some mysterious way. Given this, why have more recently created proof-of-work ...
1 vote
434 views

### What happens if I use same k twice in DSA algorithm?

To sign a message , we choose nonce k but what happens if we use same k twice to sign a message using DSA algorithm?
963 views

### Could Bitcoin be based on accounts instead, more like banks?

In banking, a user's account will have a balance, and when they spend an amount is credited from their balance. For example, the account #310 could have \$100, and spending \$10 would reduce it to \$90. ...
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### I want to know how I can express a phenomenon found in Merkle Trees mathematically

I want to know how I can express a phenomenon found in Merkle Trees mathematically. If I want to figure out which leaf node in a Merkle Tree has changed I can look at the authentication path to figure ...
257 views

### Crypto exchanges algorithms

I have noticed that if I put a buy order up - for instance - on any not so heavily traded coin, if close to the highest bid, often within 20 secs the highest bid will try to beat me. Or when I put it ...
209 views

### How can I check what mining algorithm does an altcoin use?

Where in the sourcecode files can this be checked? For example, lets get a specific coin: Chronon https://github.com/ChrononGroup/Chronon In what file can one check the mining algorithm?
103 views

### How many transactions per second can blake2s algorithm can handle?

i saw the hash functions speed (miBps) are 947 according to this website: https://blake2.net/ but how many transactions blake2s algorithm can handle? Verge uses the same algorithm right? more about ...
110 views

### Is the whole idea of proof of work or proof of stake quite unnecessary and superfluous for cyptocurrencies?

I only have a vague idea of proof of stake, but I think I reasonably understand proof of work. In the case of bitcoin, the whole hash thing business has to be combined with a mechanism to increase the ...
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### How to return Tx to mem pool from orphan block

This question is centered around the implementation of how transactions on an orphan block return to the mem pool. In my understanding, once a block becomes orphan all it's transactions (that aren't ...
2k views

### Why do I keep getting a connection lost error in Nicehash Bitcoin mining

The algorithm I'm using is daggerhashimoto. At first I thought this was because of my country blocking Bitcoin mining or something, but it doesn't work even if I'm using a VPN (vpnbook.com/freevpn). ...
60 views

### Any attack vector for Proof of Witness?

When Alice wants to send Bob some coins all she has to do is sign a transfer of ownership with her private keys and publicize that announcement until Bob is happy with the number of witnesses. For ...
1 vote
479 views

### How is Ethash a 'memory hard' algorithm if it utilizes peak GPU memory bandwidth?

According to the Ethash algorithm described here, the computation for each nonce requires a loop of 64 iterations, where each iteration reads a chunk of 128 bytes from a pseudo-random location in ...
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### Can the Antminer S3 mine Bitcoin using Blake2s algorithm?

If so, how? Nicehash can also do this, so what I'm trying to do is point my Antminer S3 to Nicehash's Blake2s stratum. But will changing the stratum URL be enough? Do I have to set up Blake2s first?
697 views

### Difference between scrypt and sha-256 mining?

So in detail my question is: are both these two algorithms different from each other?. I read somewhere that this two algorithm is used for the different cryptocurrency. if that's true. then why? ...
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### which cryptocurrency using Slasher algorithm for Proof of Stake mining process?

Ethash algorithm for PoW mining process on my own cryptocurrency. I need to use Slasher algorithm instead of Ethash algorithm for Proof of Stake process. My question is Which cryptocurrency using ...
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941 views

### Implementing NiPoPoW algorithm

Hello, We, a small team, have implemented about 95% of a breakthrough scientific proposal that is describing the NiPoPoW Non-Interactive Proofs of Proof-of-Work. You can find our source code ...
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### How an order fulfillment works

I'm trying to understand how order fulfillment algorithm works from technical point of view. Let's say I created an order to sell 0.8 BTC and buy 5400 XRP along with other orders to sell 0.35 BTC, 2....
134 views

### Understanding what is being run through Sha256

When I am running through an example for Sha256 I am not understanding how to arrive at the right answer. If I use the following Hex string: ...
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### What algorithm do bitcoin miners use to choose which tx to include in their block?

I understand it's in the miner's best interest to receive as many fees as possible for his hopefully-accepted block, hence it should include the most rewarding (fee / size) txs - up to the 1MB limit. ...
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### Does full node store all valid forks and "alternative" blocks from blockchain history?

Forks are possible when mining the blockchain and happen "all the time" during mining. This means the nodes monitoring the blockchain have recorded many forks during blockchain's lifetime, with some ...
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### At which point and how does the miner who successfully solved hash get coins? [duplicate]

When miner creates a valid block he broadcasts that to the network. It can happen that someone else did the same. So we have half nodes think that chain+A is correct, and other half that it is chain+...
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1 vote
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### Why are transactions grouped into blocks? (how are new blocks-to-solve formed)

Why are transactions grouped into blocks when put onto blockchain (PART 1)? Lets say we have just put a block on a chain and there are no blocks at the moment that users mine. At that moment how many ...
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### How bitcoin protocol checks transaction is valid (in particular that inputs are unspent)?

I'm learning bitcoin protocol theory. To pay to someone you use a transaction. In the transaction you specify some of old transactions that gave you money (so called inputs). These inputs should have ...
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### Does the 100+ GB blockchain database contain every transaction?

Does the 100+ GB blockchain database contain every transaction since the beginning, or only a digest of them? I've read Nakamoto's paper and I see: the spent transactions before it can be ...
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### Nicehash autoselected algorithm with very high difficulty

I'm new at this so please bare with me I have a couple gtx 750 lying around so I decided to give mining a try. I used nicehash, according to the site "NiceHash Miner autoselects the most profitable ...
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1k views

### if a Bitcoin mining nounce is just 32 bits long how come is it increasingly difficult to find the winning hash? [duplicate]

I'm learning about mining and the first thing that surprised me is that the nounce part of the algorithm which is supposed to be randomly looped until you get a number smaller than the target hash .. ...
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1 vote
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### Why do different currencies use different units of difficulty? [closed]

I'm trying to understand the relationship between difficulty and network hash rate. I feel like I understand it for Etherium, where the difficulty is the same as the total number of hashes the network ...
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1 vote
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### How do miners decode the input transaction?

When a transaction is broadcasted to the network, the transaction string contains the little-endian of SHA256(SHA256(X)) where X is the transaction string of input transaction. Now, since SHA is ...
376 views

### Probability of Orphaned Blocks

This is a question regarding the probability of orphaned blocks depending on the block interval. I am using Bitcoin vs Litecoin as an example. Assuming equal hash rate and number of transactions, ...
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### How do Bitcoin and Litecoin compare in scalability?

Bitcoin and Litecoin are very similar, however they differ in the hash algorithm, the block interval and reward schedule. How do these characteristics impact the scalability in terms of e.g. ...
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1 vote
2k views

### What is the difference between X11 and X11 Ghost (Gost) [closed]

I'm looking at SIBCOIN. Its algo is X11 Gost. I've been trying to see what differentiates that algo from "plain, vanilla" X11.
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### Mining and pending events

I am trying to fully understand the block chain algorithm and in particular, the consensus. My understanding is each miner has a pool of pending events -- events that have not yet been included in a ...
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44k views

### How to build a bitcoin trading bot

I'd like to experiment with bitcoin technology, crypto currency, and encryption. I thought the best way to accomplish that is building my very own bitcoin trading bot. It seems like a daunting task, ...
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1 vote
684 views

### Bitcoin mining algorithm - target - Java

Default share difficulty is 1 (big-endian target for difficulty 1 is 0x00000000ffff0000000000000000000000000000000000000000000000000000) How to calculate this? How it look like on Java code? What ...
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1k views

### Transaction signature algorithm

As I know, standard ECDSA digital signature algorithm returns two values (according to this article or Wikipedia), but transaction push services or APIs, like this one, require one string as a ...
918 views

### Own bitcoin pool miner algorithm

I receive these variables from the mining pool: job_id, prevhash, coinb1, coinb2, merkle_branch version, nbits, ntime, clean_jobs. What must I do with them? Can you write step by step formulas how ...
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1 vote
1k views

### Hashrate comparison for multiple hash algorithms

My question is about the hashrate obtained with same hardware (non-ASIC) on many algorithms. For example, I've read that Scrypt-N is about half the hashrate of Scrypt. Is that true for all hardwares? ...
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