Private Keys, Seed Phrases & Addresses Explained

Last checked 2 October 2026

General information: This article is general information only. It is not financial, legal or tax advice.

Editorial note: This article contains no affiliate links. EatCryptoPie does not recommend any particular wallet, device or backup product in this article.

Private keys, seed phrases and addresses tend to be mentioned together, but they do very different jobs. One lets other people send you crypto. The other two can be used to move it. Mixing them up can lead to sharing the wrong thing, or to not protecting the thing that matters.

This guide explains what each one is, why losing or exposing a seed phrase is so serious, how to think about backing one up, and how scams try to get hold of it. If you are new to the basics, start with What Is Cryptocurrency?

Three different things

Private key

A private key is a secret value that authorises transactions. On Ethereum, as ethereum.org explains, a private key signs transactions for an ordinary account controlled by that key (Ethereum calls this an externally owned account), so whoever controls the key can authorise transactions from that account.

From a private key, wallet software calculates a matching public key. The calculation only works in one direction: knowing the public key does not let anyone work out the private key.

Address

An address is what you give someone so they can send crypto to you. How an address is created depends on the network. On Ethereum, an externally owned account’s address is derived from its public key: Ethereum takes the last 20 bytes of a hash of the public key and adds 0x to the front. Bitcoin has several address types, so the relationship is not always that simple.

An address on its own does not let anyone move your crypto. It is not secret, but it is not private either. On a public network such as Bitcoin, anyone who knows an address can see its balance and transaction history.

Seed phrase

A seed phrase is a list of words that encodes the random data a wallet uses to generate its keys. Many wallets call it a recovery phrase; EatCryptoPie uses “seed phrase” throughout.

In wallets that follow the BIP-39 standard, each word comes from a fixed list of 2,048 words, and a phrase is 12, 15, 18, 21 or 24 words long.

The phrase is not your private key written out in words. The wallet turns the phrase (plus an optional passphrase, if you set one) into a seed, then generates a whole family of keys from that seed. That is why one phrase can back up every key the wallet creates from it. In wallets that follow the related BIP-44 standard, one phrase can also sit behind assets on more than one network.

	Private key	Seed phrase	Address
What it does	Authorises transactions	Regenerates the wallet’s keys	Receives crypto
Can someone move your crypto with it?	Yes	Potentially: it can recreate the wallet’s keys, and some setups also require a passphrase	No
Should you share it?	Never	Never	Yes, to receive. It is visible on public networks.

Where your crypto actually is

On networks such as Bitcoin and Ethereum, the record of balances and transactions is kept on the network itself, not inside the wallet app on your phone. As ethereum.org puts it, an account is not a wallet; the wallet is the application you use to interact with the account. How Does Blockchain Work? explains that shared record in more detail.

What a wallet manages is keys. Whoever can use the keys can move the crypto they control. So most of the questions in this article come down to one thing: who can use your keys?

Do you have a seed phrase at all?

That depends on who holds the keys.

If your crypto is held by a crypto platform (often called an exchange), the platform has custody. Moneysmart notes that a software wallet can be held by you, or by a crypto trading platform on your behalf. With platform custody, what you protect is the account login: your password, multi-factor authentication, and the email address linked to the account. How to Buy Crypto Safely in Australia covers securing a platform account.

With self-custody, you control the keys. If your wallet gives you a seed phrase during setup, that phrase is the backup for those keys.

Wallets do not all use the same scheme. Electrum, for example, uses its own seed system rather than BIP-39, and the Bitcoin developer documentation says wallet programs that generate keys from a seed are not expected to be fully compatible with each other. The wider custodial / self-custody choice is covered in What Is a Crypto Wallet?

Why losing it matters

If your phone or computer is lost or breaks, a seed phrase backup is what lets a compatible wallet regenerate your keys. The BIP-32 standard notes that wallets built this way do not need the frequent backups that wallets using unrelated, randomly generated keys did, because new keys come from the same seed.

If the device is gone and the backup is gone too, there is usually no way back. Moneysmart says that if you lose your private key, you usually lose the crypto. The ATO puts it more bluntly: you can’t recover a lost private key. There is no password-reset email for a seed phrase.

Two less obvious problems can also lock you out:

A forgotten passphrase. Some wallets let you add an optional passphrase on top of the seed phrase. Under BIP-39, every passphrase produces a valid wallet, but only the correct one produces your wallet. With a wrong or forgotten passphrase, the seed phrase opens a different wallet, which will usually be empty.
Restoring in incompatible software. Because wallets do not all use the same scheme, a phrase entered into a different wallet app may not regenerate the same keys. Electrum’s documentation warns that software which cannot tell a phrase is unsupported may simply show an empty wallet rather than an error. It helps to note which wallet app created the phrase and whether you set a passphrase.

If you still have a working self-custody wallet but have lost its seed phrase, you can still move your crypto, because the wallet can still use the keys. Moving it to a new wallet whose phrase you back up properly closes that gap.

Losing access can also have tax consequences. The ATO has guidance on loss or theft of crypto assets, including the evidence it expects if a lost private key results in a capital-loss claim. See Crypto Taxes in Australia for the wider picture.

Why exposure matters

Anyone who has your seed phrase (and your passphrase, if you set one) can do what your wallet does: turn the words into the same seed and the same keys. They do not need your phone, your device PIN or your app password. And because one phrase can sit behind many keys, and sometimes more than one network, exposing it can expose everything the wallet controls.

Exposure also cannot be fixed by changing a setting. A password can be changed. The keys generated from a seed phrase cannot. Once a phrase may have been seen by someone else, the fix is to stop relying on it, which means moving any remaining crypto to a new wallet with a new seed phrase. Hardware-wallet maker Trezor’s guidance, for example, says that if you suspect a backup has been compromised, you should assume it has been and move your funds promptly. The steps are below.

The same logic works in reverse. Never use a wallet or seed phrase that someone else generated, filled in or “set up for you”. If they have seen the phrase, they may be able to recreate the wallet’s keys, so it should not be treated as secret. Where a hardware wallet is designed to generate its backup during setup, it should not arrive with one: Trezor, for example, says there is no default seed, only the one you generate yourself. A device that comes with a seed phrase already supplied is a serious warning sign.

Backing up a seed phrase safely

There is no single arrangement that suits everyone, but the principles are consistent.

Write it down accurately. Copy every word, in order. Wallets that follow BIP-39 build a small checksum into the phrase, so compatible software can catch many copying mistakes, but not all of them.

Keep it off internet-connected devices. ethereum.org warns against taking screenshots of seed phrases or private keys, because screenshots can sync to cloud storage where they could become accessible to attackers. The same reasoning applies to photos, notes apps, email, messaging apps and documents stored online.

Plan for loss as well as theft. A single copy can be lost, damaged or thrown out. Bitcoin.org’s guidance on securing a wallet recommends using more than one secure location for backups. Each extra copy is also another place the phrase could be found, so the trade-off is deliberate: enough copies to survive an accident, few enough that you know where every one is.

Back up anything else the wallet depends on. If you set an optional passphrase, the seed phrase alone will not restore that wallet.

Only enter the phrase when you deliberately restore or import a wallet, using that wallet’s documented recovery process. Never enter it into a website, form, support chat or unsolicited prompt. ethereum.org says no legitimate service, support agent or website will ever ask for your seed phrase or private keys.

Moneysmart notes that a hardware wallet, which keeps private keys on a device that is not connected to the internet, may offer more protection. Whether that suits you is a separate decision, covered in What Is a Crypto Wallet? If your wallet gives you a seed phrase, that phrase still needs protecting whatever kind of wallet it is.

What a written seed phrase backup does

Together with any passphrase you set, it lets you regenerate your wallet’s keys in compatible software if your device is lost, stolen or broken.

What it doesn’t protect you from

Someone finding or photographing the backup. A forgotten passphrase or an incompatible wallet app. Scams where you approve a malicious transaction, or are talked into sending crypto yourself. Neither of those needs your seed phrase.

Scams that target your keys

The scams below either try to get your seed phrase from you, or to move your crypto without needing it. Avoiding Crypto Scams and Staying Safe covers scams more broadly; these are the ones aimed at keys.

Requests for the phrase. Treat any request for your seed phrase or private key as a scam. ethereum.org says no legitimate service, support agent or website will ask for them. The Australian Cyber Security Centre lists asking for cryptocurrency wallet seed phrases among the things police will never do. Moneysmart says a crypto platform will never ask you to share your password.

Impersonation. In late 2025, Scamwatch and the Australian Cyber Security Centre warned about callers posing as Australian Federal Police or other police officers, followed by a second caller posing as a crypto platform. The callers cited fake cybercrime report references, asked for one-time PINs and seed phrases, and tried to get people to move crypto into a so-called “cold storage” account. If someone contacts you about your crypto, end the call and contact the organisation using details you have found yourself.

Fake wallets and websites. Moneysmart warns that scammers build fake crypto platforms and wallet sites that look real, create fake crypto apps that can appear on legitimate app platforms, and use phishing pages that capture the details you enter. Find wallet software independently rather than through links sent to you.

Malicious transactions and permissions. Not every theft requires your seed phrase. Moneysmart warns about “mystery” tokens that appear in a wallet looking valuable, where trying to sell them triggers a smart contract that takes the wallet’s legitimate tokens. The details vary between scams, but interacting with an unexpected token can lead you to sign a malicious transaction or grant a spending permission. On Ethereum, for example, the ERC-20 token standard lets an address approve a “spender” to withdraw tokens from it, up to a set amount. Permissions like this let tokens be moved without the scammer needing your seed phrase or private key. If you did not expect a token, do not interact with it.

Recovery offers. Scamwatch warns that money-recovery scammers pose as government agencies, lawyers, law enforcement or charities, may claim they can track down stolen cryptocurrency, and ask for fees, personal information or remote access to your device. Its advice is to never accept offers from anyone who says they can get your money back.

If your seed phrase may have been exposed

Act quickly, but do not let urgency push you into a second mistake.

Stop. Do not send more money or crypto to anyone involved, and do not share anything else.
If crypto or money went through a platform or bank, contact them immediately. Moneysmart says they may be able to help stop transactions.
If a self-custody seed phrase was exposed and you can still access the wallet, promptly move what remains to a new wallet with a new seed phrase, set up on a device you trust, and back up the new phrase properly. Do not reuse the old phrase, and do not accept help from anyone who contacted you.
Get support. IDCARE, a not-for-profit national identity and cyber support service, offers free help on 1800 595 160.
Report it. Report scams to Scamwatch, and report cybercrime through ReportCyber or on 1300 CYBER1 (1300 292 371).
Keep a record. Note what happened and when, the addresses and transactions involved, and who contacted you.
Expect follow-up approaches. Treat anyone offering to recover lost crypto for a fee as a likely scam.

The bottom line

A private key authorises transactions. In a seed-based wallet, the seed phrase, plus any passphrase you set, can regenerate the wallet’s keys in compatible software. An address is for receiving, and can be shared.

Keep the seed phrase accurate, offline, and somewhere you will find it again. Only enter it when you deliberately restore or import a wallet through that wallet’s documented recovery process, and never give it to anyone: no legitimate person needs it. Remember too that protecting the phrase is not the whole job. Approving a malicious transaction, or being persuaded to send crypto yourself, does not require it.

Careful key handling reduces avoidable losses. It does not remove the risk that crypto itself can lose value.

Understanding Private Keys & Seed Phrases