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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Validation of New Blocks [duplicate]

Basic mining question: Once a miner solves the block and comes up with the block hash, how are the other nodes in the network incentivized to validate that hash?
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How to use API of BTC.com

I'd like to get some information(BTC's difficulty, hash rate). I think I can get that from api of BTC.com, and I checked github of btccom, but I can't mount api with python. How Can I use btccom api(...
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GH/s is bigger than TH/s [duplicate]

How does BAIKAL X10 make more money than AntminerS9 although BAIKAL X10 Only 10 GH/s and Antminer S9 14 TH/s ? So, which one is bigger GH/s or TH/s? I am confused.
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Hash pointers: Are hashes of data used as addresses?

I am wondering how hash pointers are implemented in reality. Currently, I am reading this article about hash pointers. According to this website a hash pointer allows both to request data and to ...
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1answer
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What subjects do I need to study before I am capable of understanding the mathematical problem being solved in Bitcoin mining?

I am a post graduate electrical engineering student, specialising in digital electronics. I would like to foray into ASICs for bitcoin mining. But first I need to understand the mathematics of Bitcoin ...
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Review of “equitable” proof-of-work systems

One major criticism against usual SHA-based proof-of-work systems in main cryptocurrencies (except the ecological concerns) is the fact that, years after years, it's more and more dominated by a ...
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1answer
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Where is debug.log file in Bitcoin source code?

I am running 64bit Ubuntu 17.04, I am following this tutorial for creating a new altcoin. I am up to section 7, here to be exact: The first time you run the compiled code (daemon or qt), it will say "...
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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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1answer
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Why the leading zeros in the desired hash pattern?

Why are leading zeros desired in the block chain hash? I have searched the internet but cannot find why.
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1answer
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nBit to leading zeros in Block Hash

I am trying to understand how can I check if my Block Hash satisfies or not the nBits. For example, for block 506679 (https://blockchain.info/block-index/506679): nBits: 404454260 Block Hash: ...
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Total number of hashes performed for bitcoin purposes?

I would like to estimate the total number of hashes (double SHA-256) that have been performed for bitcoin purposes. As an estimate, I downloaded mining stats, massaged the numbers (assuming the rate ...
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Why Bitcoin Mining requires “Hash Guessing” problems, even though Consensus algorithm exists to tackle BFTP?

This post on CoinText explains Purpose of Hashing in Bitcoin Mining: The purpose of all the extra work is to prevent the traitors from sending false messages but serves no other purpose. The idea ...
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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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How are thousands of transactions put into a block?

As much as I hate to admit it, I am not very tech savvy, and as such, I am fairly confused about the concept of the blockchain. I understand that the chain holds information about previously approved ...
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1answer
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What if is there is no solution to a block?

Please let me know if I understand something wrong. Let's say I want to create a new block and verify previous transactions. To do this, I need to: Choose which transactions I want to include in my ...
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1answer
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is it possible to replace the cryptography and public key algorithms in Bitcoin?

Is it possible to replace the cryptographic algorithms used in Bitcoin, such as the hash algorithms and the elliptic curve public key cryptography? Does this require a soft fork or a hard fork?
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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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1answer
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Can I restore a Litecoin wallet with Public / Secret?

I apogolize if this has been asked, I have spent several hours trying to figure this out. I found an old document of my with a Litecoin Public and Secret key. I don't have a *.dat file, is this a ...
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1answer
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How can blockchain.info show the output address of a transaction when the output address has never been used in any other transaction?

I've stumbled across a transition on blockchain.info where the output address was displayed even though the output address had never been used in any other transaction. How can blockchain.info know ...
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How to produce a Hash160 bitcoin address?

tl;dr How should one perform Hash160, using most basic tools? ==================================================== Hi, I'm trying to figure out, how transactions work in bitcoin. When I choose ...
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What would happen if two blocks had the same hash?

Consider the following scenario: January 2016 block A gets submitted. Its hash is 0001010. January 2017 block B gets submitted. Its hash is also 0001010 (collision). 10 minutes later, block C gets ...
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2answers
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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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1answer
381 views

With the current hashrate, how does it still take 10min to solve a bitcoin block?

No matter how high the difficuly is (or how low the target is), I don't understand how the Bitcoin network takes an average of 10 minutes to solve each block. For any given block header, there are ...
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Why do we need block hashes in blockchain?

I believe there are around 3 types of overall hashes that we deal with in Bitcoin. block hashes Merkle tree hashes (makes transactions tamper proof by hashing them up to the Merkle root) public-...
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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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1answer
635 views

BitMinter Hash rate

I checked on BitMinter (https://bitminter.com/) and it says my computational power is 2058Thps, is that a good thing for bitcoin mining, i'm rather new to the mining community and am uncertain. I ...
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How can someone mine bitcoins at billions or trillions of hashes per second when the nonce is only 2^32 in size?

According to another similar question on Bitcoin Stack Exchange, https://en.bitcoin.it/wiki/Block_hashing_algorithm shows how the mining algorithm works for Bitcoin. The problem is, it shows the ...
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1answer
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Getting Hash160 of bitcoin address

How to get hash160 address in string using bitcoinj ,I tried the following code NetworkParameters params = TestNet3Params.get(); String ads = "n1XZMMm3ikh97Mr8JVnnahfugad2DRcVrB"; Address address = ...
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2answers
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Sustainability of current hashing

I'm a bitcoin/blockchain layman. I'm just getting my head around the hashing of blocks and the increase in difficulty (number of zeros) required as more miners get involved. I understand this is to ...
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1answer
346 views

A short program to mine a block

Anyone can give step-by-step explanation about the code below (if possible, with a c/c++ equivalent)? import hashlib, struct ver = 2 prev_block = "...
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Why do two miners get different hashes for the same list of transactions?

According to the Bitcoin Wiki: it is extremely unlikely for two people to have the same Merkle root because the first transaction in your block is a generation "sent" to one of your unique ...
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1answer
418 views

how make own gitian-sigs end detached sigs?

How make own gitian-sigs end detached-sigs. I cannot find any useful info. Where i try see it's always start with "you already have .assert and .sig . but how they create ?
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1answer
715 views

How to tell which part of the previous tx I need to make the hash to sign for an old given tx?

I have recently been taught (here) how to create the hash to sign for a given "input script" for an existing transaction. I then sought to test my abilities and sought out a difficult ...
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Why is difficulty measured in a hash’s leading zeroes?

I understand how generating a SHA-256 hash containing any specified sequence requires lots of guessing and checking. The longer the specified sequence, the more rarely that it will appear. And I ...
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1answer
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Is the HashOfThingToSign (used in signature generation) the same for each input of a transaction or is it different for each input of a transaction?

Does a transaction with 50 inputs have 50 different hashofthingtosign, one for each input, or does it just have one that is used for all the input scripts?
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How would one go about acquiring the HashofThingtoSign from this old transaction?

How would one go about acquiring the HashofThingToSign that is used in the "Signature Generation" equation for this example transaction such that it could easily also be applied to any other ...
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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
984 views

Verifying a P2SH transaction script by hand. How should I concatenate OP CODES in order to hash the script?

I'm reading this: Transaction 40eee3ae1760e3a8532263678cdf64569e6ad06abc133af64f735e52562bccc8 paid to P2SH address 3P14159f73E4gFr7JterCCQh9QjiTjiZrG. You can see the redeem script in ...
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1answer
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How to generate random addresses from public key such that they're recoverable later using pub key only

I head that from a public key, you can generate random addresses just by adding a nonce to the public key. Then, you can regenerate all these addresses again when you need, right? If my wallet has ...
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1answer
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API for getting the Hash-of-thing-to-sign

Does anyone have, or have access to a simple API that can calculate the hashofthingtosign for old transactions along the blockchain? I'm just looking for something simple to see what the "...
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Double Hashing Merkle Trees [duplicate]

I under that merkle tree use double hashing (HA = SHA256(SHA256(Transaction A)). Curious for answers to the following: Why is there a need to hash it twice? What is the difference between hashing it ...
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1answer
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Why check for multiple nonces despite finding a golden nonce?

I'm still new at trying to understand the entire idea surrounding the mining process. I read the following: When mining, you are given a set of data to perform hashes on. As you noted, this is done ...
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1answer
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Is the hash of the previous block included in the block header?

What the title says above, but for more clarification I am asking whether the hash of the previous block header is part of what is hashed to create the header of the new block? Like what are all the ...
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finding a fast way to calculate a nonce

I found a way for ultra-fast nonce calculation, based on my own method. Does it makes sense to introduce such method, or the complex way of nonce calculation has some advantages? Thanks!
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More than one valid hash block

Discovering a new block is a task about generation of millions of hashes in order to find one valid hash, which is a hash less than the current target. The question is: Are there more than 1 valid ...
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1answer
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ScriptSig content during signature (quadratic hashing)

As far as I know, the quadratic hashing problem came from the fact that every time a transaction is verified (or signed), the "unsigned transaction" that is hashed and verified changes depending on ...
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What's a good repo to fork if you want to create a blockchain like a “Math” coin or Curecoin. (mining equations, not hashes)

I want to create my own crypto currency and I want to know what's the best github repo to fork when it comes to making a blockchain that's based off of getting the miners to do mathematical ...
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Why does the hash-rate change so drastically?

I've been watching the global estimated hash-rate, as estimated by blockchain.info. While it is clearly increasing, it also varies around 20% day-to-day. Yesterday, it was around 4,325,000 TH/s. ...
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1answer
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When mining, does one also include Merkle root data into block header when testing for hashes?

I am just a beginner trying to understand technical details of bitcoin. As far as I know, the Merkle root of a block works to provide summarizing hash of list of transactions. And according to my ...
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1answer
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How long does it take to perform a single SHA256?

I'm not talking about hashes/s, but specifically, the amount of time required to perform a single SHA256 on the fastest computers known. How long does a very fast ASIC take to perform one SHA2? Is ...

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