Questions tagged [hash]

This tag should be used for questions related to hashes. A hash is the output of a hash function, a function which .is a mathematically reproducible but irreversible process that takes in an arbitrary length input and produces a fixed length output. The same input will always result in the same output. Hashing is central to Bitcoin mining as well as the generation of Bitcoin addresses.

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1answer
44 views

Will a recursive sha256 run over all 2^256 inputs before a collision?

Will a recursive sha256 run over all 2^256 inputs before a collision? Here'a a python program showing my question - will this loop for 2^256 times - given endless memory or will it terminate before - ...
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2answers
748 views

Adding instead of concatenating hashes in Merkle trees

Why aren't the hashes combined using a commutative operation such as addition instead of concatenating them? Any possible vulnerabilities or security flaws? thanks for your time and efforts.
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Bitcoin Core ZMQ “hashTx”

Bitcoin Core ZMQ messaging system has hashtx along with 4 other topics. But nowhere it is documented whether the transactions that comes from hashtx are confirmed transactions which are added in a ...
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1answer
29 views

Is a timestamp in bitcoin different than just the “stamp of time”?

In the "References" section of Bitcoin's whitepaper, Satoshi Nakamoto points to three papers that serve as inspiration for digital timestamping. When you read those documents it is clear ...
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1answer
32 views

Why number of zeroes in bitcoin hash is increasing? [duplicate]

I know currently to mine a block there needs to be 19 leading zeroes in the hash, but why is this number increasing?
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1answer
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Calculate block hash is different in regtest?

I'm able to calculate the block hash in mainnet and testnet, but I don't get the right hash in regtest. I mint +3000 blocks and I get the block with height 3000 bitcoin-cli getblock $(bitcoin-cli ...
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How do bitcoin verifies block hash after new hash have been submitted by Miners? [duplicate]

I want to know how at the end of Bitcoin server block hashes are verified after it has been submitted by a miner. Do they already have a previously calculated block hash DB or something else? I m new ...
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How many transactions are there in one block

What I understand: When a transaction is made , miners compete to validate it and create a hash . If one miner creates the hash and more than 51% of miners agree on the validity .Then the a block is ...
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1answer
38 views

What would be an example for an insertion into the blockchain?

I'm reading the paper The Bitcoin Backbone Protocol: Analysis and Applications. On page 21, definition 8 reads: An insertion occurs when, given a chain C with two consecutive blocks B and B, a block ...
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84 views

Is there a CUDA binary to convert a brainwallet string to a BTC address?

I am looking for a CUDA program which will take a single argument, a brainwallet password, and output a BTC address. After reading through several threads on how to convert passwords to public keys, ...
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1answer
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College Economics Student in Support of Crypto Looking for Live Hashrate Data

I am a college economics student doing a Thesis project in support of the long term viability of Crypto. Does anyone know where I can get live Hashrate data for free or for sale? I appreciate it - ...
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1answer
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What will happen when a collision in SHA256 be found?

Would the protocol migrate to another Hash Algorithm inmediatly? What would be the next? SHA3 or BLAKE 2?
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Parsing transaction hash from rawblock data

I got block raw data next url https://blockchain.info/rawblock/00000000000000000002447735c7723ee9188322c0938e6587866a4458b9135f?format=hex Can I find transaction hash in url used python?
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Can I get all block header data like the SPV node?

It hasn't been long since I studied Blockchain. I only need header data, not all block data, for study purposes. As far as I know, the SPV node stores only the block's header information. Can i get ...
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Padding the blockheader in sha256

The block header size is 80 Byte (640 bits) so we must pad it to a multiple of 512 (In our case to 1024) like this: (blockheader in binary)+1+00000.....000+1010000000 where "1010000000" is ...
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2answers
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Is that proved that for each block there is always nonce value which will make block hash to start by n count of 0

Sorry for the obvious question, but I'm looking for a mathematical prove. Block header is calculated as a concatenation of the following values. Version hashPrevBlock hashMerkleRoot timeStamp Bits ...
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23 views

Solution to the same TXID from 3 different client

Someone sent me some bitcoins.... then I had some other clients sending me the same txid that they also made a payment, but I received only one payment.
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1answer
121 views

Calculate Z from r and s

Can anyone explain me any clearly answer or code in python with examples how we can calculate Z value from r and s and inputs outputs order ?? I search in google and youtube and i not saw any ...
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Why do these 2 blocks have the same hash for the block reward? [duplicate]

Could someone explain to me that why do the hashes of the block rewards in these 2 blocks be the same? https://www.blockchain.com/btc/block/...
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1answer
44 views

How do miners earn partial bitcoins?

I know that the miner who has the hash matching with the bitcoin's root software gets to stamp the block and put it onto the blockchain (correct me if I'm wrong). Accordingly, that miner takes the ...
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1answer
143 views

Why do miners need a nonce if the timestamp changes the hash of the block?

As the title says. If the timestamp is constantly changing with every guess, why does the miner also include the nonce? Is it because they're mining too fast for the timestamp to change?
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What does the version number in the blockheader represent

While looking up how a block get mined I stumbled over the version number in the header - which is used to "keep track of changes to the protocol". But even in the last 5 blocks of the chain (at the ...
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1answer
31 views

How does the daemon get a transaction via a hash

I am wondering how the daemon gets the transaction data from just a hash. I'm NOT asking how i can get it, i know i can get it via the rpc, i am asking how the daemon does it behind the scenes. Does ...
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2answers
487 views

How to find Reused R values

I use software from https://github.com/ca333/rng-scanner , I try to find r that is reused. from the software I found results Bitcoin Address : 1GQdrgqAbkeEPUef1UpiTc4X1mUHMcyuGW In Input NR : 141 ~ ...
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2answers
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Why are hashes base16 (hex) encoded rather than base58 encoded?

BTC sha256 hashes are hex encoded (as sha256 spits out bytes not a string), why is this? Surely using base58 would be more efficient as would use less space (would output a shorter string)
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1answer
112 views

Get invoice amount from payment request - LND REST API

I'm using the REST API of my LN node to generate and pay invoices. I would like to know how to get the invoice amount/value in sats from the payment request I receive. I found this : https://api....
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1answer
103 views

How to generate the hash of public key in Bitcoin [closed]

I'm trying to hash the public key with SHA256 and then ripemed160 and get the hash. but it gives the wrong hash Public key: 2b4632d08485ff1df2db55b9dafd23347d1c47a457072a1e87be26896549a8737 Hash ...
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1answer
38 views

Where do I include my wallet address after finding the hash less than target - bitcoin

Please help me understand the logic behind mining a bitcoin from scratch. I want to create a bitcoin miner, it will not receive any blocks from any pools. All should be done inside the miner. So, I ...
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1answer
51 views

Double SHA256 giving me an incorrect value with this code VB.net

I'm trying to build a bitcoin miner. I have generated the message successfully, but I can't get the double SHA256 correctly. The value I'm getting is incorrect. What is wrong with this code? Private ...
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1answer
33 views

If i have 42 tera hashes of mining power, how long will it take me to mine a block solo, and if i join a mining pool, how much bitcoin will I get? [duplicate]

If i have 42 tera hashes of mining power, how long will it take me to mine a block solo, and if i join a mining pool, how much bitcoin will I get? I am intrested in buying 4 Bitmain Antminer T9+.
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2answers
547 views

Bitcoin Difficulty granularity

Difficulty adjusts by very granular percentages to target for 10 minutes blocks. But adding another zero at the end of the chain of zeroes from the header hash requirement for a valid block would ...
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1answer
322 views

A security need for Bitcoin to fork to quantum resistant algorithm in a few years?

in just a few years I believe that quantums will exist that break asymmetric ciphers, and bitcoin is based on asymmetric ones like public-key-cryptography, correct? Symmetric algorithms are supposed ...
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1answer
92 views

How many bits of entropy is a Bitcoin address?

I've seen references to 160 bits of entropy, but I'm not sure if this is universal or just applies to the old address format.
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2answers
251 views

How to get block header hex?

I am trying to research hash functions and I want to be able to use bitcoin's mining outputs as hashes. I am curious about where the actual hex value of the data that generates that hash with a lot of ...
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1answer
342 views

How can I find a hash with leading zeros

I came across a similar question that was asked but the answer didn't seem quite complete. Coding is completely foreign to me and I have spent some time trying to solve with no success. I am trying ...
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1answer
50 views

How does Bitcoin utilize cryptography and secure hash algorithm (SHA) to link records in the blockchain?

I am wondering how Bitcoin uses cryptography and secure hash algorithm such as SHA256 to link the records in the blockchain. And if possible I think it will give me a better understanding if there is ...
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0answers
42 views

Blockchain.info explorer doesn't recognize my hash

Blockchain.info doesn't recognize my tx. Can someone explain this. My wallet is debited. The transaction is unconfirmed too.
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1answer
2k views

Longest unconfirmed transaction?

I recently tried to make a transaction with coinbase. In a hurry I put no fee though. It's still unconfirmed and blockchain.info doesn't recognize my hash. But my btc qt wallet is debited. My question ...
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1answer
37 views

What would be the effect on the number of leading zeros hash generation if bitcoin increase its nonce size from 32 to 60 or 100 bits?

If Bitcoin increases its nonce size from 32 bits to double or triple the size, how will it affect the speed of getting the right hash with the required number of zeros?
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1answer
33 views

How to transfer hash power from one pool to another

Is it possible to transfer hash power from one pool to another? If yes, how?
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2answers
80 views

How do more leading zeroes make it more difficult to find a block?

A couple of articles describing the process of mining do say that the more miners are in the network, the more 0 numbers are included in the encoded hash of the particular block. I cannot find an ...
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0answers
242 views

How get the public key to hex script? like command decodescript of bitcoin core

If I want to recreate the command decodescript of bitcoin core? how is the process for decode the script P2PK? So I'm writing for personal exercise the Bitcoin script decompiler, form moment I have a ...
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1answer
18 views

How are the requirements of the hash for mining a new block determined?

How are the requirements of the hash for mining a new block determined? Is it published or a message is sent?
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74 views

How to sign an Altcoin transaction manually with 2 inputs and 2 outputs

So i'm working with the altcoin denarius which has the following raw TX structure. This is a transaction I am try to sign: Original: ...
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Bitcoin Module - Hash512-EVP_ByteToToken

Is there any standalone software modules created which allow the user to complete the following: 1. Enter in passphrase 2. Enter a given salt 3. Enter the number of rounds I am looking ...
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1answer
133 views

How many hash calculation is needed to reach one BTC?

What I am asking for is a formula and it's source of numbers to put in there and calculate how many hashes must be calculated to get 1 bitcoin today(or every other day in future)? For example, if I ...
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1answer
78 views

When changing transaction data in a block change the hash of previous block?

If i only manually change the data on the block without touching/modifing the already calculated hash, then hash on the block its still valid because its already saved and was not touched ... so, ...
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1answer
53 views

How exactly does the network know if the miner has put forth a valid proof of work?

If all that the miner needs to do is find a hash with a certain number of leading 0's of the block's header, couldn't they just find a random hash with the required number of 0's that isn't ...
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2answers
411 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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1answer
39 views

How is the PRIVATE KEY actually created in the first place?

How is the "Private Key" created in the first place? I understand that once you have your wallet, you will also gain access to your public key and private key... But in order to have a wallet ...

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