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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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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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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Electrum's “script hash” form with NBitcoin?

I've come across how scripts are hashed in the electrum (stratum) protocol implementation by looking at the docs. I'm using NBitcoin, and I've tried to generate this hash from a segwit address, first ...
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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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Is the current hashcash proof of work system vulnerable to attack by quantum computer? [duplicate]

I've been caught up in the post-quantum cryptography scene for a little while now, and understand that the RSA or ECC cryptography inherent in a cryptocurrency network can be easily broken by a ...
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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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471 views

What would happen if two public keys had the same Base58 hash?

If two different public keys had the same Base 58 hash, what would happen? Could one key spend money in the other account? What would happen to the monies received by the shared base58 hash?
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How does changing transaction data in a block change the hash of previous block?

I am reading this article, within which it mentions that "Imagine this for a second, a hacker attacks block 3 and tries to change the data. Because of the properties of hash functions, a slight ...
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What will happen when SHA 256 needs to be replaced?

MD5 used to be the hash algorithm. Everyone loved it, but now, not so much. What will happen to bitcoin if flaws are found in SHA256 in the future?
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I am just wondering what are the methods which can hide all the transactions and also able to validate transactions in an block chain?

I am new to block chain and was looking at how block chain work mainly proof of stake based . They check validity by going through all the transactions which is something concerning as everyone can ...
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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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119 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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Sorry newbie, I dont get the PoS block creation, to much contradiction

I am sorry for the repeat question but I cant find a clear answer. Most of the time PoS isnt explained in detail (only explaining the advantage) and a lot of sources contradict each other and now I am ...
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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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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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Public key vs Bitcoin address [duplicate]

As i've read on many websites and papers, the bitcoin address is made by hashing the public key. And i've read that that's done because we don't want the public key to be public until money is spent. ...
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What are the unnamed parts of the segwit/bitcoin cash raw tx shown and how do I get them as shown?

There are three parts to this. Shown here. Part 1. This string is found at the final form of the raw tx: ...
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Why is HMAC-SHA512 used on root the root seed to create master private key and chain code in HD wallets?

The process is depicted in this picture. Specifically, given that the root seed was derived using PBKDF2 (with 2048 rounds of hashing with HMAC-SHA256 already), why do we undergo an additional pass of ...
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889 views

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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35 views

How chaining the blocks protect against altering data?

I am confused with the block chaining, as i know a block header contains a reference to the previous block header hash with the merkle root and other fields. This header hash is related (computed) to ...
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Getting the wrong txid for coinbase transactions

I'm trying to hash transactions to get the txid. I get the hex values from blockchain.info. I get the correct hash for all transactions except for the coinbase when I hash it twice. Is there something ...
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1answer
3k views

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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What is Bitcoin's “genesis hash”?

From Lightning Network documentation: Used in several of the BOLT documents to denote the genesis hash of a target blockchain. This allows nodes to create and reference channels on several ...
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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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837 views

What is preventing me from simply constructing a hash that's lower than the current target?

I just started learning about Bitcoin, and something I can figure out is why miners have to use a random process (hashing a nonce) to get lower than the target. For example, if the target is ...
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How difficult is it to confirm a Bitcoin Block?

If I have done the math right to come up with this hash, to confirm a true block and this is a confirmed hash. You can look it up here Bitcoin Block #570240 ...
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1answer
799 views

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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Hash rate of the average PC/Top end PC [duplicate]

Hi I was wondering if anybody had any idea about what the hash rates are like with PCs released fairly recently. I'm sort of looking for figures to use for an average user if they wanted to use their ...
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93 views

ScriptCode field in P2SH-P2WPKH BIP-143 Test Vector

I'm trying to understand the meaning of scriptCode in the context of spending a P2SH(P2WPKH) UTXO. I've already read the following answer to a similar question, but it does not fully address my ...
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How may bitcoins hash algorithm be secured in the future from quantum computing brute forcing?

Other threads already answer very clearly that quantum comps could easily "break" /attack bitcoins chain. Now: Are there any ideas among the bitcoin devs circulating out there, how to save bitcoin ...
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Hashing Transactions for Mining

After reading that Mining involves Taking a root hash of a transaction and combining that hash with a nonce it is required to find a number that is equal or below the given target, i was wondering if ...
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Uniquely identifying a UTXO

I see two ways: Txid + index Txid + script hash Pros of the txid + index: Simple and short Cons of txid + index: It relies on array iteration being deterministic and all third party ...
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Swift implementation of bitcoin transaction creation

Is there a well known and widely used Swift implementation for creating raw Bitcoin transactions and getting their hash (SegWit and Non-SegWit) of signing? If not, is there a reference document that ...
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49 views

Hash rate : Algebraic Equation

I recently made a post on stack, Calculate hash rate in IOS, in hopes of deciphering how the hash rate is calculated when benchmarking performance. The reason I wanted to do this is to compare against ...
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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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where in the source code is the the proof of work checking the blockheader hash and nonce?

Where in the source code do we check whether hash(blockheader*nonce) < Difficulty In fact, the line I found is as follows: https://github.com/bitcoin/bitcoin/blob/v0.17.0.1/src/pow.cpp#L87 My ...
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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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211 views

Bitcoin-core how to get all transactions hashes?

Please, can anyone help me how to get all transactions hashes? How to browse all the transactions hashes used in blockchain? P.S. How simply get a list of all transactions IDs (as a simple text list) ...
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148 views

How specific are ASIC's design? Can they single hash SHA256?

I understand that Bitcoin's ASICs are a highly optimized piece of equipment and, therefore, are also very specific. My question: are they able to do a single (or triple?) SHA-256 hash at all? And, ...
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Trying to understand why hash value is more secure from hash algorithm

I am currently studying in college in the US and was actually curious about bitcoin and cryptocurrencies as a whole. I started looking on free university sites like Stanford university and New York ...
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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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Proof-of-Stake: How to ensure immutability of the blockchain?

In Proof-of-Work, a miner tries to solve PoW puzzle based on the hash of previous block, such that in case of changing block B_i, all blocks after that (blocks B_i+1, B_i+2, ...) are no longer valid ...
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How does transaction authentication between buyer and seller look for?

I am new to cryptography and would like to understand how a digital signature works between a buyer and a Bitcoin seller. How does transaction authentication between buyer and seller look for? Please ...
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1answer
47 views

Create master public key after HMAC-SHA512

I have that result after hash_pbkdf2 5B56C417303FAA3FCBA7E57400E120A0CA83EC5A4FC9FFBA757FBE63FBD77A89A1A3BE4C67196F57C39A88B76373733891BFABA16ED27A813CEED498804C0570 left 256 bits are: ...
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44 views

Newly generated coins

New to BTC world so my question is how and what can I do with newly generated coins what's the process and how to see balance of that in wallet? Can I send those to paper wallet
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Mining Block header bit reversing

While trying to understand the mining process and checking in python..... i am puzzled with which info from/to pool are in Little Endian, which one needs reversing in building the block header + ...
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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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How are Bitcoin Signed Messages generated?

Ledger Nano S and other pieces of Bitcoin software and hardware can sign messages using the private key associated with an address. Doing this, I get the following output: -----BEGIN BITCOIN SIGNED ...
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Is it possible to accurately map hashing power to network size?

Let's say we have a network with n nodes in it. Is it possible, when the hashing power of the network is calculated after a proof-of-work, to accurately estimate n with an algorithm taking the ...
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in transaction, what is 'hash' data?

i'm studying Bitcoin: A Peer-to-Peer Electronic Cash System Satoshi Nakamoto and this paper introduce a transaction model. (above picture) but i don't understand what is 'Hash' means exactly i ...