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.

Filter by
Sorted by
Tagged with
2
votes
1answer
231 views

Who decides what the next, correct Nonce is?

As I understand finding the correct Nonce is the basis when hashing transactions for Proof of Work. How and where is this decided in the ecosystem what the next Nonce is? In my limited understanding ...
2
votes
1answer
4k views

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 ...
2
votes
2answers
6k views

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 ...
2
votes
1answer
333 views

Question about getblocktemplate

I'm having trouble understanding getblocktemplate. From https://en.bitcoin.it/wiki/Getblocktemplate, I see how to build the block header and then begin hashing by incrementing the nonce, the same as ...
2
votes
4answers
2k views

What exactly is the input for the Hash pointer in block k+1?

I'm not sure how to ask this question clearly so I will ask it three different ways and hopefully someone understands me. Is the input for the hash pointer in block k+1 just the transactions in block ...
2
votes
2answers
483 views

What is the average number of hashes it takes to mine bitcoins?

I'm just curious about this. I'm not sure if the length of zeros in the hash result is directly proportional to the probability, or how to calculate this.
2
votes
3answers
281 views

Does a miner (or mining pool) who has 10x as much hashing power have 10x the odds of mining a block?

I heard somewhere that joining a mining pool logarithmically increases your odds of mining a block.. is that for some reason true? Or was it someone who didn't know what they were talking about and ...
2
votes
1answer
806 views

How do the clients agree on the target to hash for? [closed]

Edit: They do not agree on a specific target hash. Any hash lower than or equal to the difficulty is sufficient. This means clients only have to agree on difficulty.
2
votes
1answer
58 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 ...
2
votes
1answer
1k views

How do I concatenate two hashes in Python?

Concatenating and double SHA-256 hashing "a751efbeabe73bdf9d08df5760104feff915d9d807d4c62178cdeb98d8c25f43" with itself "a751efbeabe73bdf9d08df5760104feff915d9d807d4c62178cdeb98d8c25f43" should ...
2
votes
2answers
110 views

Why we must reference the entire txid for each output we want to spend?

Suppose I want to spend from 3 unspent outputs. I must reference the txid of these unspent outputs. Suppose they are: eb36eca9a06fbe68278ad3e7d16d10ed02e22ad891ed59ef2b84ed4a49e8a6d2 ...
2
votes
2answers
580 views

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 ...
2
votes
1answer
101 views

Whats the public key required for in a transaction?

In figure 1 of the original paper by satoshi, why include the public key of the next owner in the hash?
2
votes
1answer
1k views

How does a proof of work limit of `~uint256(0) >> 20` translate into a difficulty of `1 / 2^12`?

In the Litecoin source it is written: static CBigNum bnProofOfWorkLimit(~uint256(0) >> 20); // Litecoin: starting difficulty is 1 / 2^12 How does that compute? ~uint256(0) >> 20 is ...
2
votes
2answers
1k views

Are any hashes (Tx or block) actually stored in the blockchain?

...or is each client responsible for storing hashes for blocks and transactions in their own database? So when I send a transaction, I indicate the prev_out by its hash, and I just assume everyone on ...
2
votes
1answer
46 views

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 ...
2
votes
1answer
246 views

Probability of block rewards

Assume that there are only three mining pools, all with the same hashing power, mining for bitcoins in the bitcoin network. Which mining pool is most likely to get the block reward? Do you all think ...
2
votes
1answer
477 views

Using the Merkle Root to prove the integrity of a block's transactions

I understand that a Merkle Root is the hash of hashes of hashes (etc.) of transaction pairings within a block that ultimately results in one 'Root' hash. Changing anything about any of the original ...
2
votes
1answer
390 views

What causes quadratic hash problem?

I read ScriptSig content during signature (quadratic hashing) discussing quadratic hash problem. Quadratic hash problem is the issue that signing (or verifying) transaction time grows with the square ...
2
votes
3answers
712 views

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 ...
2
votes
1answer
128 views

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 ...
2
votes
1answer
1k views

How is the extra nonce formatted?

I'm trying to understand how a block is put together. From here, I know that the extra nonce used to be in the format: pblock->vtx[0].vin[0].scriptSig = CScript() << pblock->nTime <&...
2
votes
1answer
1k views

Can't find correct z1 & z2 for transaction

I've been trying to understand the issue and repeat Willem Hengeveld's answer, but I think I'm failing at getting correct script for hash. I'm looking for this transaction, my scripts are: ...
2
votes
1answer
217 views

Why is this transaction stuck?

https://blockexplorer.com/tx/286fefb79f1b0a14526997e8c7bcb4bd7a5665c953586f6bbcd09e441b192d3f this is my transaction blockchain hash This is first time I've actually seen something like this - the ...
2
votes
1answer
2k views

bitcoin address to Hash 160 public key : not consistantly reversible?

When I use blockchain.info tools or bitcointoolkit.info tools to convert an address, such as 1MCNpVGDY7BGjJyWZL5FJZiaVkQEiuxy8H to a hash 160 public key : I get ...
2
votes
1answer
496 views

How is hash rate of mining hardware calculated

The mining hardware does a double sha-256 hash of the header while mining. Is each sha-256 operation counted when determining the hash rate or is the whole sha256(sha256(header)) counted as one hash? ...
2
votes
1answer
383 views

Why does the hash come before the signature?

The first figure in the original paper of Satoshi is a diagram of transactions. This diagram seems to indicate that the transaction data is hashed before the sender's signature is appended. Why not ...
2
votes
1answer
250 views

Why is a double hash of the previous transaction included in Txin?

In Txin, there is a double hash of the previous transaction. Why? What purpose does that serve? How is this data used later?
2
votes
1answer
10k views

What is a “share rate”?

What is a "share rate" one can find in a mining pool dashboard? I understand what a hash-rate is, and how that applies to myself (miner), as well as to the pool or the network. I also understand to ...
2
votes
1answer
2k views

Sample worked Stratum example

I need some help trying to verify that my implementation is correct or not. I'm trying to make a Stratum mining client. All byte orders are as is directly received from the server, without endian ...
2
votes
0answers
31 views

How to generate a coinbase transaction?

I am creating a miner in C++ for solo mining, and am struggling to create the proper coinbase transaction. Say I have a bc1 address, like bc1qfc7fameteuguetm0kfzypnvf2ju6wppdvj6tkc , what would be and ...
2
votes
0answers
100 views

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 ...
2
votes
2answers
208 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.
2
votes
0answers
222 views

Is my understanding of Blockhain Endianness correct?

I know questions on this topic have been asked to death in a number of different ways. I also know that what endian order refers to specifically is dependent on context. What I want are some ...
2
votes
0answers
81 views

Blake-256 genesis block generation helpint

I'm making my own coin and get problem to generate genesis for my fork. Genesis need to be blake-256. I was found this git https://github.com/lhartikk/GenesisH0 and tryed to use this script, i also ...
2
votes
0answers
178 views

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 ...
2
votes
0answers
64 views

Mining , hash and Nonce [duplicate]

I lack something in my understanding of how the mining process works. If a miner has to loop over a block and re-calculate it's SHA256 for only 2^32 (the amount of different nonce values possible) ...
2
votes
1answer
408 views

Where is the spec of HashCash so that I can implement it in Java from scratch?

I would like to implement HashCash in an efficient/fast/garbage-free way. Is there a spec to do so? How can someone go by implementing HashCash from scratch?
2
votes
1answer
1k 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, ...
2
votes
0answers
3k views

BFGminer can't find my NanoFury on Raspberry Pi

Related: BFGminer can't find my NanoFury! Posted on the RPi Exchange as well https://raspberrypi.stackexchange.com/questions/14753/bfgminer-cant-find-my-nanofury-on-raspberry-pi Forums: https:...
2
votes
0answers
463 views

attempting to decipher a cgminer share.log

Here is 1 entry from a share processed in a feathercoin mine pool: 1367788723,accept,ffffffffffffffffffffffffffffffffffffffffffffffffffffffffff070000,http://mining-foreman.org:11341,GPU1,1,...
2
votes
2answers
5k 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 ...
2
votes
1answer
570 views

BIP32 HD Wallets: HMAC vs. “just” Hashing the Seed

In A. Antonopoulus' Mastering Bitcoin (2nd edition) on page 106, there is a nice illustration showing how the basis for a BIP32 HD Wallet is generated: So here is the one thing I don't understand ...
1
vote
2answers
430 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-...
1
vote
2answers
1k views

Would it be possible to have an ARM hashing based Cryptocurrency?

This was something that popped into my mind while I was thinking about CPU Only Alt-coins. Would it be possible to have an ARM-based coin? That is, a coin that could only be mined on ARM devices (...
1
vote
3answers
3k views

two people with same PUBLIC address, how will people/network know how to deliver bitcoin

I understand that a bitcoin address is a combination or more than one kind of encryption and entropy, and I also understand how improbable it is that the same address will get generated at the same ...
1
vote
1answer
95 views

Why is Target < Blockhash?

I am currently trying to validate a blocks hash against its target in python3: This is a block in the Blockcypher testnet, and I am using this formula from the Bitcoin Wiki. block_hash = '...
1
vote
1answer
959 views

Bitcoin - Is the <pubKeyHash> in scriptPubKey already hashed?

In Bitcoin protocol, to set the output of a transaction you need a scriptPubKey which is in the following format. scriptPubKey = OP_DUP OP_HASH160 <pubKeyHash> OP_EQUALVERIFY OP_CHECKSIG Is &...
1
vote
1answer
99 views

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 ...
1
vote
1answer
2k views

Why is the hashrate getting so high?

The Bitcoin hash rate is MASSIVE right now. What exactly causes the hashrate to increase?

1 2 3
4
5
9