Bitcoin

The first decentralized digital currency, with no bank or middleman.

The illusion of control

In the traditional system you trust third parties (banks, states) that can censor, freeze or devalue your money. Bitcoin is a global, open, peer-to-peer network where no one is in charge.

The hash

A hashing algorithm (SHA-256) turns any data into a unique fixed-size fingerprint. Change a single letter and the whole output changes: this is the avalanche effect.

The block chain

Each block holds transactions and the previous block’s hash. Tampering with a block breaks the chain and the network rejects it. That is immutability.

Mining

To add a block, miners solve a puzzle with computing power (proof of work). Difficulty adjusts so a block is found roughly every ten minutes.

A programmed scarcity

There will never be more than 21 million bitcoins: a programmed scarcity, often called “digital gold”.