Wallets, keys and the seed phrase

This page explains what a wallet holds and how to keep it safe. That includes your seed phrase, the words that back up your wallet. By the end, you can tell your address and your key apart, store your seed phrase offline, and know what to do if it leaks. You need none of this to practice: paper trading on Trenches uses no wallet, no key and no seed phrase.

Each section names the Trenches lessons behind it. Some are in the free Memecoin starter. The rest sit further along the Crypto road, the app's path of lessons, which opens in order. Most of those are in its section on custody: who holds the keys.

What does a wallet hold?

A wallet is the app you use to see your coins and prepare payments, but the coins are not inside it. They are recorded on the network, the shared record every wallet reads. A balance on your screen is only a view of that record (What wallet software does). What your phone holds is a copy of your keys, the secrets that approve payments.

So losing your phone loses that copy, not your coins. If you kept your recovery information, the backup of your keys, you can restore control on another device (Recovery information restores control). For many wallets, that backup is the seed phrase explained below.

On an exchange, a service that holds coins for its customers, the company holds the keys. Your balance there is what it owes you (A balance on an exchange is a claim). With your own keys, control and responsibility are both yours. A payment sent to the wrong address has no support desk that can reverse it (Read a self-custody setup).

Your address is public, your key is private

A receiving address tells someone where to send you coins. It is public: you can hand it out, and nobody can use it to spend (Give a payer receiving information). Spending needs your private key, a huge secret number used to sign, or approve, each payment. Getting paid never requires sharing it.

Most addresses are calculated from your key, but only one way. No known practical method can work back from an address to the key, so sharing your address is safe.

Whoever copies your private key can sign exactly as you can. The network has no password reset (A private key provides signing control).

Scammers also make lookalike addresses that copy the first and last characters of an address you pay. They send you a tiny payment from one, so the fake sits in your history. Next time you copy an address from there, you may copy theirs: a trick called address poisoning (A familiar contact name is not enough). Before any payment, compare every character, middle included, with a source you trust.

What is a seed phrase?

Many wallets back up your keys as a recovery phrase, often called a seed phrase. It is 12 to 24 words that the wallet makes from random data, each word from a fixed list of 2,048 words. From those words, the wallet can rebuild your keys on another device, usually for every account it made from them.

Order is part of the data. The same words in a different order describe different data. So write each word down with its number (Keep the words complete and in order). A sentence you make up is not a seed phrase, because words people choose are far easier to guess.

Part of the last word is a short check on the others, and it catches only some mistakes. When a wallet accepts a phrase, that shows the words fit the format, not that they are your words.

Easy to mix up: three secrets with similar names. Your app password unlocks the wallet app on one device. Your seed phrase rebuilds your keys in any compatible wallet, and no password can bring it back. A passphrase, used by only some wallets, is an extra secret added to the seed phrase (A passphrase and a password do different jobs).

A mistyped passphrase opens a different, usually empty wallet, with no error message. So if a restored wallet looks empty, that is not proof your coins are gone (Restoring changes access, not history).

A copy is not a second wallet: two paper copies still mean one set of coins. Restoring rebuilds keys on a device. It moves no coins and never undoes a past payment.

Where should you keep your seed phrase?

A backup has two jobs: stay private, and still be there when you need it. Offline storage, on paper or metal that never touches the internet, keeps it away from hacked accounts and devices. Store it somewhere locked where only you get in (Store the backup where only you can reach it). It still needs guarding from fire, water and visitors.

Photos, cloud notes, email drafts and chat messages are online copies. They can sync to other devices, sit on an online service or leak in a breach.

Even part of the phrase leaks more than it seems. Say a photo shows 11 of your 12 words. The last word has 2,048 possible choices, but its built-in check leaves only about 128 that fit (Why guessing fails and disclosure does not). A whole phrase is practically impossible to guess, but a list of 128 can be checked almost instantly.

Losing every copy is the other failure. If the device fails too, the coins may be out of reach for good. No company can reset the keys. A second copy in another place survives one fire, but it is one more place to guard (Own the backup responsibility).

Later lessons weigh that trade-off (Storing a seed phrase) and have you rehearse a restore on a fresh test wallet (Restoring from a seed phrase).

Nobody else ever needs your seed phrase

Wallet makers state that they will never ask for your seed phrase. A request for it is one of the clearest warning signs in crypto (No one else needs your recovery phrase). It may come from a support agent who messages you first, a pop-up with a copied logo, or a site that offers to check your word order.

The phrase belongs in one place: a wallet app you installed yourself, from a source you checked, on your own device, when you choose to restore. If you need help, describe the problem without typing any of the words.

A copied logo, a staff badge or pressure to hurry proves nothing about who is writing. So leave the message and open the service yourself, through its app or a bookmark you trust. Two later lessons practice exactly that (A support claim is not identity, Do not let the message choose the route).

A recovery scam often targets people who already lost funds. It promises to get them back for a fee up front, or for the phrase itself. The FBI warns that these services take the fee, then vanish or ask for more. Neither the phrase nor the fee brings funds back.

Spotting scams and low-quality tokens covers the other messages built to take wallets.

What if your seed phrase leaks?

Exposure means someone who should not have your phrase may have seen or copied it. It is not yet theft, so check the payment history before you call it that. But it is not safety either: whoever holds a copy can move the coins at any time (Treat an exposed phrase as compromised).

The easy fixes fail. A new app password locks one installation, while the attacker restores the wallet on their own device. Deleting the photo or message cannot recall a copy someone already saved.

The response has three parts. Set up a new wallet with a brand new phrase, away from the device you suspect. Move the remaining coins there. Then stop using the old wallet and every account it made, since they all come from the exposed phrase.

Send nothing more into the old wallet, not even for a fee. Anything sent there can be taken, and automated scripts may take it at once. A rushed move still needs its checks of network, destination and fee (Responding to a compromised wallet).

One more habit for any wallet: keep some SOL for fees. Every move pays a network fee, a charge for processing it. On Solana, where most memecoins trade, that fee is paid in SOL, the network's own coin. A wallet full of other coins but no SOL cannot pay it, unless someone else has agreed to cover it (Check the asset in a changed example).

Even a trade that fails still pays its fee. Later lessons on reading on-chain data show how to set SOL aside for fees (Funding a trading wallet, Fees, rent and SOL reserve). They size it from the costs you plan, not a round number. From paper to real: the way there, with the risks covers the rest.