Proof-of-work system facts for kids

A proof-of-work (POW) system is like a special puzzle. It's designed so that finding the answer to the puzzle is very hard and takes a lot of effort or computer power. But, once someone finds an answer, checking if it's the right answer is super easy and quick. This system is used to make sure people do some "work" before they can do certain things, like adding new information to a digital record. It helps keep things fair and secure, preventing cheating or spam.

How Proof-of-Work Systems Function

Proof-of-work systems are used in many digital technologies, especially in cryptocurrencies like Bitcoin. They help secure transactions and create new digital money. The main idea is to make it costly to create fake information or to flood a system with too much data.

What is a Hash Value?

Before we look at examples, let's understand a "hash value." Think of a hash function as a special digital blender. You put any data into it (like a number, a word, or a whole book), and it always spits out a unique, fixed-length code, called a hash value. Even a tiny change to the original data will create a completely different hash value. It's like a digital fingerprint for information.

Finding a Specific Hash

Imagine you are given a very specific digital fingerprint, like this code: c75cb66ae28d8ebc6eded002c28a8ba0d06d3a78c6b5cbf9b2ade051f0775ac4

Your task is to find the original positive number that creates this exact fingerprint using a special tool called SHA256. To do this, you would have to try every number, starting from zero, and put it into the SHA256 tool until you find the one that matches the given code.

Even though checking each number is fast, trying millions or billions of numbers takes a lot of time and computer power. This "work" is the proof that you put in the effort to find the correct number.

Finding a Hash with Specific Rules

Here's another example. What if you need to find any piece of data whose SHA256 fingerprint starts with at least eight zeros? Like this: 000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f

In this case, it doesn't matter what the original data is, as long as its digital fingerprint starts with those eight zeros. Finding such data is very difficult because you have to keep trying different inputs until you get a hash that fits the rule.

However, once someone finds a piece of data that works, it's super easy for anyone else to check it. They just run that data through the SHA256 tool, and they can instantly see if its fingerprint starts with eight zeros. This shows that "work" was done to find that specific data.

Images for kids

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  Bitcoin electricity consumption as of 2021

See also

In Spanish: Sistema de prueba de trabajo para niños