Who invented Bitcoin?

No one really knows for sure. But the person (or persons) most directly responsible used the pseudonym Satoshi Nakamoto when they authored a white paper in October 2008 called "Bitcoin: A Peer-to-Peer Electronic Cash System." It was published on a small mailing list for cryptography fans.

What's so special about Bitcoin?

Bitcoin had qualities that no previous form of digital cash had ever gotten quite right:

• Decentralized: No one person or group owned or controlled it.
• Peer-to-peer: No third party (like a bank) needed to confirm and approve
• Borderless: Bitcoin could be moved easily across the world, for smaller fees and at faster speeds than traditional money transfers.
• Immutable: It's nearly impossible to change or tamper with blockchain transactions.
• Prevents double-spending: This was a problem many prior digital currencies had tried to crack before.

What is double spending?

Double spending is a potential exploit in cryptocurrencies that allows malicious actors to spend the same coins two or more times. To do this, fraudsters can send a transaction with a minimum fee and then immediately override it by increasing the fee (so miners will be incentivized to verify the more profitable new transaction first) and redirecting funds to a different address. Bitcoin's verification protocol can prevent this from happening.

How is Bitcoin created?

Picture gold under the ground. We know it's there, but its value is hidden until a miner digs it up. In the Bitcoin world, a miner unearths Bitcoins by using expensive computers to solve cryptographic puzzles in real time that "mine" bundles of transaction records ("blocks") to the blockchain.

Miners get rewarded for their efforts with a small amount of new Bitcoins, and the mining reward is halved every four years as a measure to slow the creation of new Bitcoins. In Satoshi Nakamoto's white paper, they said only ever be 21 million Bitcoins could be mined—so at the current rate, all Bitcoins will be mined by somewhere around 2140.

How do you acquire Bitcoins?

There are two ways to acquire  Bitcoin:

• You can buy some using fiat currencies ($, £, or € for example) at crypto exchange sites. You’ll need a digital wallet and you'll get a set of keys that you'll use to access your holdings.
• You can become a miner by buying a mining rig, though the equipment is very expensive, and it takes a while to become profitable.

What is a Bitcoin wallet?

Like a regular wallet, it’s a place to keep your valuables—but digital. (Read more about crypto wallets in our handy guide.)

When it comes to Bitcoin, those valuables are your keys (strings of numbers and letters), held on a piece of software you can store on your phone, the web, or a computer. Or to be extra safe, you can write down your keys somewhere completely offline—aka "cold storage."

In order to buy and sell Bitcoin, you need both a private and a public key.

Your public key is what you share with other people so they can send you Bitcoin. Think of it as your address: It's OK for others to know it.

Your private key shouldn't be shared. When you trade, you use your private key to authenticate that it's you who's requesting to send or receive Bitcoin.

Cheat Sheet