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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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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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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Why is it impossible to modify a transaction in the blockchain?

Many pages (including Wikipedia) say that it is impossible to modify a transaction which is already in the blockchain included. But why is it so difficult?
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2answers
425 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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1answer
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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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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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2answers
178 views

API for multiple blockchains

Is there an API to get data for multiple blockchains? Most blockchain explorers already offer an API but I'd like to be able to get information for different blockchains through the same API.
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1answer
248 views

How do I double SHA-256 the header of block #59,500?

I'm not sure how to combine all of this information. https://blockchain.info/block/00000000096af43105123c499521e1d131d172e7e1bf2ed0843290a921f1f6a7 Version 1 Time Bits 470771548 (is this the right ...
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1answer
34 views

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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2answers
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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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Do HTLC transactions work today or do they need a new soft-fork?

I thought that HTLCs were just a kind of a script construct that would allow to unlock funds for a period of time, which can be unlocked to anyone that provides the original string that matches the ...
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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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Signature digital algorithm in bitcoin, to what will it change in the future?

in follow-up to the question: 85202 There, @Ugam Kamat wrote ""ECDSA is the first thing that can get vulnerable with quantum computer. signature will need to move to post quantum world much before ...
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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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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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The warpwallet challenge 2

here you can find a public challenge aimed to brute force a brain wallet private key, derived from 8 char long [a-zA-Z0-9] passphrase with a salt of "a@b.c". Is it possible to adapt an hashing ...
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2answers
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Generate private key from a bip-39 seed phrase?

I'm able to generate a new private key and associated public addresses using bitcoin-core, but what I really want to do is generate a new private key from a 24 word seed phrase. I'm not sure how to go ...
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Where is Double hashing performed in Bitcoin?

where in the Bitcoin Protocol is SHA256(SHA256(x)) performed and why?
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1answer
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How do I get hash to verify transaction?

If I have the public key and signature for a transaction how do I get the hash value that is used in verify(hash, sig, pubkey). I want to know how to work backwards from a raw transaction to get it, ...
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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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Why do transaction/blockchain based gambling sites use such complicated methods for proving fairness?

Doesn't the block hash or the transaction id provide enough entropy (for example, by using block_hash % 37 to generate a random number between 0 and 36)? Block Chain Roulette determines the lucky ...
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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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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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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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310 views

Any source for a visualized SHA-2?

Is there any source that visualizes how SHA-2 works (including internals) with animated video or an interactive web page?
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1answer
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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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1answer
11k views

What's the relationship of Bitcoin addresses to public keys?

A Bitcoin wallet can handle multiple private keys. In ECC, you can have 2^256 private keys, and for each key, you can have 2^256 public keys. Assuming that's right (please correct me if I'm wrong), ...
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1answer
613 views

How do you verify a block manually?

From my understanding, you simply need to use a SHA256 function to hash the block's header (Block hash and merkle root) then add the nonce at the end like this article explains. However, I can't ...
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3answers
2k views

Is it possible to convert Bitcoin Miner to Litecoin Miner?

I have 90Gh/s Bitcoin Miner and its almost useless for Bitcoin Mining with current difficulty. By changing the Linux software installed in it can I convert this Bitcoin Miner to Litecoin Miner? I am ...
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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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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
139 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
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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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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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How can I generate a vanity Bitcoin address?

I once found a program that was capable of creating Bitcoin addresses with specific words in them, but can't find it now. Is there a trusted program, in the Ubuntu repositories for example, that can ...
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1answer
104 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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2answers
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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
99 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
36 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
50 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
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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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3answers
635 views

Which is the smallest hash that has ever been hashed?

Let's assume, the hash 00000000000000000024c0bdbec66a889778c00bc69be0a96cbbd98b75c3ce09 of block #499644 is smaller than 0000000000000000002d429f39afec70c938e888c3417d690bbc85e83529991c of block #...
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1answer
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Two identical R value finding z value from two transaction

tx1 from the trans1 i got Input Scripts 30450220262e481b6d8905b5adba67aff05eb8261501b0a9434c0b7f043d00cf8d23c91b022100bf82c0d212f30d3a0599e9b879516d762eaf5688ab83787cf470e99af5a6917101 ...
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1answer
320 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
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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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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