What Are Public/Private Keys?

And Why They Matter in Bitcoin

**Imagine having a bank account where you are the bank.**

No middlemen. No customer service lines. Just you — and full control of your money. That’s what Bitcoin makes possible. But it all comes down to one thing: your keys. Let’s break down what public and private keys are, why they matter, and how to use them safely — without getting too technical.

The Basics: Think of Keys Like Digital ID + Digital Lock

- Your public key is used to generate shareable bitcoin addresses so that others can send you bitcoin, just like your bank account number or email address. You can freely share the generated bitcoin addresses to facilitate transactions. You can generate as many addresses as you need, and you can use a new address for every single transaction, which gives extra privacy benefits.

- Your private key is like your PIN or password. It’s secret, and it proves you’re the rightful owner of the Bitcoin.

When you hold the private key, you hold the Bitcoin. Lose the private key… and it’s gone — forever. That’s why you’ll often hear:

“Not your keys, not your coins.”

How Public and Private Keys Work (Made Simple)

When you use a Bitcoin wallet, it:

1. Generates a pair of keys – one public, one private.

1. Derives your Bitcoin address from the public key (this is what others use to send you Bitcoin).

1. Uses the private key to digitally “sign” transactions — proving you’re the owner.

Here’s what happens when you send Bitcoin:

- You enter someone’s Bitcoin address.

- Your wallet signs the transaction using your private key.

- The Bitcoin network checks that signature using your public key.

- If valid, the Bitcoin moves to the new owner — simple, secure, and trustless.

All of this cryptographic magic happens under the hood. Your wallet does the hard part — you just need to protect your keys.

Where Do Keys Come From? (And Where Are They Stored?)

Most wallets generate your keys for you using secure, random number generation. You don’t really need to understand the math — just know this:

- A strong Bitcoin wallet will also give you a seed phrase (usually 12 or 24 words).

- This phrase is like a backup master key to recover your wallet if it’s lost or damaged.

- Anyone with this phrase can access your Bitcoin — so store it like gold.

Wallets + Keys: What You Need to Know

Term	What It Means
Public Address	Your receiving address — safe to share
Private Key	Your password — keep it secret, keep it safe
Seed Phrase	A backup of your private key — store it securely
Wallet	The software or device that manages your keys
Custodial Wallet	You don’t hold the private key — someone else does
Non-Custodial Wallet	You hold the key — full control, full responsibility

Security Reminder: Your Keys = Your Bitcoin

If you lose your private key or seed phrase, no one can help recover it. There’s no “forgot my password” button in Bitcoin. That’s why using a reliable hardware wallet for savings and a hot wallet for everyday use is a smart approach. And always remember:

Not your keys, not your cheese. 🧀

Try This: Reveal and Backup Your Bitcoin Keys

You’ve learned what public and private keys are. Now let’s explore how they’re created, where they live, and how to protect them. Try the following activity:

1. Download a non-custodial wallet (if you haven’t already) → Good options: Sparrow Wallet (desktop), Zeus or BlueWallet (mobile)

1. Create a new wallet
  - - As you set it up, you’ll be given a 12- or 24-word seed phrase.
  - - Write this down on paper (offline) — i.e. not in your phone or online cloud storage.
  - - This seed phrase is your master private key — anyone with it can spend your Bitcoin.

1. Explore your keys (optional for the curious wannabe power users) In Sparrow Wallet, go to “Keystore” or “Wallet Info” to view:
  - - Your public key (xpub or address)
  - - Your private key (WIF or hex format — don’t share this)

1. Try signing a message
  - - Some wallets let you sign a message using your private key and verify it with your public key.
  - - This shows how Bitcoin proves ownership without revealing your secret.

1. Practice recovery (optional)
  - - Delete the wallet from your app (without Bitcoin in it), then restore it using your seed phrase.
  - - You’ll see your wallet reappear — just like magic.

TL/DR: Why Keys Matter to You

- Your public key is used to generate Bitcoin addresses (used to receive).

- Your private key gives you access and control (used to send).

- Your wallet generates and stores these securely — but only you are responsible for backing them up.

If you own the keys, you own the coins. If you don’t… someone else does.

Further Resources

- READ: Understanding Your Bitcoin Keys – by Shinobi (article)

- LISTEN: Why You Must Own Your Private Keys – What Bitcoin Did (podcast)

- WATCH: Your First Bitcoin Wallet – BTC Sessions (YouTube)

Ready to Take Full Control of Your Financial Future?

Secure your future, easily, with HardBlock.

Start saving in Bitcoin with HardBlock, Australia’s longest-running Bitcoin-only exchange.

Disclaimer

We believe Bitcoin is the hardest money and best savings technology in the world — but this isn’t investment advice. Always do your own research before buying Bitcoin (or anything else). Questions? Reach out anytime: support@hardblock.com.au