Private Keys & Public Keys: The Bedrock of Bitcoin Ownership

Some theory first (Good to know, not need to know) - Key pairs are created using cryptographic algorithms built on mathematical problems that are easy to compute in one direction but hard to reverse—these are called one-way functions. The strength of public-key cryptography lies in keeping the private key secure and inaccessible to anyone, while the public key can be safely shared without putting your security at risk.

When bitcoiners say “Not your keys, not your coins,” they’re talking about private keys—the foundation of Bitcoin ownership.

Let’s break it down:

What is a Private Key?

A private key is a secret—like a master password—that gives you access to your bitcoin. Think of it like the key to a digital vault containing your bitcoin. Anyone who has your private key can spend your bitcoin. If you lose it, your bitcoin can be lost forever. If someone else finds it, your bitcoin is no longer yours. Thus the phrase - "Not your (private) keys, not your coins."

What is a Public Key?

From your private key, a public key is generated. This public key is used to create your bitcoin address, which you can share with anyone to receive funds. Think of your public key like your bank account number—safe to share. But never confuse this with the private key.

What Public Keys Enable

• Receiving bitcoin
• Verifying signatures
• Being shared openly, even posted on websites

What Private Keys Enable

• Signing transactions
• Spending bitcoin
• Proving ownership of your funds

How to Protect Your Private Key

1. Never share passcodes or passwords to your bitcoin apps or devices with anyone.
2. Back up your wallets —using secure methods like writing down Seed Words on paper (store it safely!) or using Cryptosteel products.
3. Never click pictures of your Seed Words and store it online or on your phone.
4. Test your backup—make sure you can recover your wallet if your device is lost.