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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24 views

How can properties of hash function cause insertion , copy and prediction? [closed]

So definitions are as fallow : insertion occurs when, given a chain C with two consecutive blocks B and B′,a block B'' created after B′ is such that B , B'', B′ form three consecutive blocks of a ...
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Decoding raw transaction [closed]

I have several raw transaction hashes that when I go to decode on blockchain it says; Trying to access beyond buffer length What does this mean? I got these hashes from an encoded UTC file i sent to ...
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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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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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44 views

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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21 views

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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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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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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35 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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135 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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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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223 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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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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83 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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80 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
33 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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46 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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32 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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539 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
316 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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68 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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178 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
200 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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38 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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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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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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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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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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183 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
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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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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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51 views

BIP32 HD Wallet vs HMAC vs Hashing

I've been working on a website which will be caring out various cryptographic operations. On the website users can post Ads. Each Ad has a monotonically increasing unique ID. For each Ad, I would like ...
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38 views

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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100 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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43 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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51 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
405 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
36 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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53 views

Method to create P2SH address

I am trying to create a htlc smart contract manually by writing a script and finding the hex using the btcc compiler. Now node A has to create a transaction using that hex and lock money in that p2sh ...
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1answer
23 views

Doubt regarding hashing function in Merkle trees

From what I read, say in a block, there are 4 transactions. The hash value of transactions A and B are combined together to get the hash AB. Same goes for transactions C and D to get hash CD. Later AB ...
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53 views

OP_EQUAL not working properly

I went to https://siminchen.github.io/bitcoinIDE/build/editor.html to try some bitcoin scripting and I wrote this script: <1PUzZ61FSVTn12CafJC85Vy1ts3BoFcXdU> OP_HASH160 <...
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129 views

Is this a collision attack or a 2nd-preimage attack?

This question revolves around Bitcoin Optech newsletter #51 (1) and an email thread from the bitcoin-dev mailing list (2). I asked the same question in a reply-email of the newsletter and the response ...
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292 views

What happens if I send a XRP transaction to a blank TAG when I was supposed to send to a specifc TAG?

I sent XRP to a blank TAG while I was supposed to send to the éxchange's TAG. The address is the one from the exchange but the TAG was left blank. The exchange says that they can't recover the money. ...
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19 out of 24 words of BIP39 passphrase (brute-force last 5?) [duplicate]

I have managed to lose 5 words of my 24 word Ledger Nano S recovery phrase. I have words 1-19 but I am missing words 20-24. I have significant holdings on the wallet so would very much like to recover ...

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