Reference
Password and seed phrase glossary
Short, plain definitions of the words you will meet across this site. Articles link here the first time a term appears.
- 25th wordCrypto secrets
- The common nickname for a BIP39 passphrase, an optional extra secret added to a seed phrase that opens a separate wallet.
- 2FA (two-factor authentication)Everyday passwords
- A login that needs two kinds of proof, usually a password plus a code from your phone. A stolen password alone is then not enough.
- AddressCrypto secrets
- The public identifier you share to receive crypto. It is derived from a public key and is safe to share, though blockchain activity is public.
- Air-gappedCrypto secrets
- Never connected to the internet or to an online computer. Air-gapped devices pass data through QR codes or memory cards.
- Authenticator appEveryday passwords
- A phone app that creates short-lived login codes for two-factor authentication. Safer than codes sent by text message.
- BIP39Crypto secrets
- The public standard that defines how a random number becomes a list of 12 to 24 words from a fixed list of 2,048.
- BlockchainCrypto secrets
- The public shared record of transactions that a cryptocurrency network keeps. Your funds are recorded here, not inside your wallet.
- BlocklistEveryday passwords
- A list of common and known-stolen passwords that a website refuses to accept when you choose a new one.
- Brute force attackEveryday passwords
- Trying every possible password until one works. Long random passwords make this impractical.
- ChecksumCrypto secrets
- A small piece of data built into a seed phrase that lets a wallet detect most mistakes in the words.
- Credential stuffingEveryday passwords
- Taking usernames and passwords stolen from one site and trying them automatically on many others. It only works when passwords are reused.
- CustodialCrypto secrets
- When a company, such as an exchange, holds the keys to your crypto for you. You log in with a normal password.
- Data breachEveryday passwords
- When information held by a company, such as customer emails and passwords, is stolen or exposed.
- Derivation pathCrypto secrets
- The set of directions a wallet follows to produce a specific key from a seed. Wallets may need the same path to find the same funds.
- EntropyEveryday passwords
- A measure of how unpredictable a secret is, counted in bits. Each extra bit doubles the number of guesses an attacker needs.
- ExchangeCrypto secrets
- A company where you can buy and sell crypto. Coins left on an exchange are held by that company.
- FirmwareCrypto secrets
- The software that runs inside a hardware wallet. Updates never require you to enter your seed phrase on a website.
- Hardware walletCrypto secrets
- A small dedicated device that keeps your private keys away from your computer and signs transactions on its own screen.
- HashEveryday passwords
- A one-way scrambled fingerprint of data. Websites should store a slow, salted hash of your password rather than the password itself.
- InfostealerEveryday passwords
- Malware that copies saved passwords, session cookies and wallet files from a device in seconds.
- Legacy contactEveryday passwords
- Someone you choose in advance to access or manage an account after you die.
- Master passwordEveryday passwords
- The one password that unlocks your password manager. It usually cannot be reset, so make it strong and keep a safe backup.
- MultisigCrypto secrets
- A wallet setup that needs several keys to approve a transaction, such as two out of three, which removes a single point of failure.
- PasskeyEveryday passwords
- A newer way to log in that uses a key stored on your device instead of a password. It resists fake login pages.
- PassphraseEveryday passwords
- A password made of several random words. In crypto, the same word also refers to the optional BIP39 passphrase, or 25th word.
- Password managerEveryday passwords
- An app that creates, stores and fills in strong, unique passwords for you, protected by one master password.
- PhishingEveryday passwords
- A trick that uses a fake email, message or website to get you to hand over a password or other secret.
- PINEveryday passwords
- A short numeric code. It is safe enough on a device that locks after a few wrong tries, but too short to use as a password online.
- Private keyCrypto secrets
- The secret number that authorizes spending from an address. Anyone who has it controls the funds there.
- PSBTCrypto secrets
- Partially signed Bitcoin transaction, a standard format for passing unsigned transactions between a computer and a signing device.
- Public keyCrypto secrets
- A number calculated from a private key, used to verify signatures and create addresses. It cannot spend funds.
- Seed phraseCrypto secrets
- A list of 12 or 24 words that can rebuild every key in a crypto wallet. Also called a recovery phrase or mnemonic. Never share it.
- Self-custodyCrypto secrets
- Holding your own keys rather than leaving crypto with a company. You gain full control and take on full responsibility.
- Shamir backupCrypto secrets
- A way to split a wallet backup into several shares, of which only a set number are needed to restore it. Defined by the SLIP39 standard.
- SIM swapEveryday passwords
- An attack in which a criminal moves your phone number to their own SIM, so that your calls and login codes go to them.
- Token approvalCrypto secrets
- Permission that you give a smart contract to spend your tokens. Old or unlimited approvals can be abused.
- Two-factor loginEveryday passwords
- Another name for 2FA. See 2FA (two-factor authentication).
- WalletCrypto secrets
- An app or device that holds your keys and lets you send and receive crypto. It does not hold the coins themselves.
- Wallet drainerCrypto secrets
- A malicious site or script that tricks you into signing an approval or transaction, which then empties your wallet.
- XpubCrypto secrets
- An extended public key. It cannot spend funds but reveals all the addresses in an account, so keep it private.