APRIL 15
Nodes
Bitcoin’s Independent Rule Checkers
The Signal
A Bitcoin node checks transactions and blocks for itself. It accepts only what follows Bitcoin’s rules.
The Reading
Imagine a money system with no master computer. Ordinary computers around the world check information for themselves.
The program doing this job is called a node. It receives transactions and blocks, then checks Bitcoin’s rules. Is the spending authorised? Has the same bitcoin already been spent? Is the proof of work valid? Has the miner created only the amount allowed?
Inside the engine room, claims are not enough. A miner may spend electricity finding a winning hash, but the block is still only a proposal. If one rule is broken, nodes reject it. If correct, they add it to their verified view of the shared book and pass it onwards.
Anyone with a suitable computer and internet connection can run a node. No application, licence or name is required. Now, tens of thousands run across the planet. Many do not appear on public maps. They can leave, return later and catch up. There is no master node. Running a node lets someone verify Bitcoin without asking a company what is true. Privacy tools can also hide its internet address from other nodes.
Miners propose. Nodes check. Bitcoin’s rules decide.
First Principles
A full node independently checks transactions and blocks.
Miners cannot force nodes to accept an invalid block.
Anyone can run a node without asking Bitcoin for permission.
Today’s Challenge
Place a bowl on a table. Put one coin and one button beside it.
The rule: only coins enter.
Pick up the coin, check it and place it inside. Now pick up the button. It may be round. It may be the same size. Someone powerful may demand that you accept it. It still does not meet the rule, so leave it out.
You have just acted like a Bitcoin node.
The bowl represents your verified copy of the shared book. The objects represent proposed blocks. A miner may spend enormous amounts of money and energy producing a block, but that does not make it valid.
If the block follows every Bitcoin rule, the node accepts it. If one rule is broken, the node rejects it.
Valid goes in. Invalid stays out. No exceptions.
Tomorrow’s Signal
Your Node, Your Rules