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8 votes
Accepted

What are hash functions used for in bitcoin?

In consensus rules: There are script opcodes that perform hash operations on the stack: OP_SHA256: SHA256 OP_RIPEMD160: RIPEMD160 OP_SHA1: SHA1 OP_HASH160: SHA256 followed by RIPEMD160 (very ...
Pieter Wuille's user avatar
7 votes
Accepted

How can a collision attack reveal the private key?

If the attacker just tries random public keys and guesses the correct one, they obviously won't be able to spend the funds. What they can do is try random private keys and derive the public keys from ...
Vojtěch Strnad's user avatar
5 votes
Accepted

What is the numeric precision of Network Difficulty?

Is this definition of Difficulty correct? Yes. If yes, is it accurate to think about Difficulty as a type of proportion or ratio? Yes, it is how many times harder current blocks are to mine than ...
Pieter Wuille's user avatar
3 votes

What is the numeric precision of Network Difficulty?

is it accurate to think about Difficulty as a type of proportion or ratio? I think of it as just a number that is an abstract representation of the probability of a mining attempt failing. As with ...
RedGrittyBrick's user avatar
2 votes

Address Reuse and ECDSA Concern

Address reuse is chiefly a privacy issue: because your UTXOs share the same output script, they are obviously controlled by the same entity. Reusing addresses reveals your receiving pattern, and if ...
Murch's user avatar
  • 75.7k
2 votes

How do you verify a block manually?

Copied below is a short python script that walks through the verification, using input values for block 505400 from the blockchain.com block explorer: import json import hashlib block={} #inputs ...
mti2935's user avatar
  • 727
1 vote

In what order is the blockheader hashed?

They are hashed in the order they appear in the network serialisation: block The block message is sent in response to a getdata message which requests transaction information from a block hash. ...
RedGrittyBrick's user avatar
1 vote

What is one word seed word exactly?

As you can see in the code, the word is hashed using SHA256 to get the private key. Because private keys in Bitcoin have 32 bytes, you can't just use any word directly as a private key, and one way of ...
Vojtěch Strnad's user avatar
1 vote
Accepted

Verify Hash from bitaddress.org without the original HTML file

Obtain the HTML containing the javascript. $ wget https://raw.githubusercontent.com/pointbiz/bitaddress.org/master/bitaddress.org.html --2024-02-16 12:19:23-- https://raw.githubusercontent.com/...
RedGrittyBrick's user avatar
1 vote

What is TXID?Is it used to calculate merkleroot

There are two types of transaction identifiers, TXID and WTXID. TXID represents the result of a double SHA256 of the serialized transaction form without witness data. It is used to uniquely identify ...
LeaBit's user avatar
  • 950
1 vote

How are transaction hashes calculated?

I've come across this several times when trying to come up with an easy way to calculate a txid, and I finally decided to try and write a little script to do the same. I used built-in libraries and ...
rpseu's user avatar
  • 111

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