Get the extension Crypto wallet glossary
34 words you meet when you hold crypto yourself, explained in plain language, with what each one means for the safety of your funds.
Wallets
- Air-gapped walletAn air-gapped wallet keeps the private key on a device that is physically cut off from every network: no Wi-Fi, no mobile data, no Bluetooth, no cable. Transactions reach it and leave it as QR codes, so the key itself never travels.
- Cold walletA cold wallet is any way of holding crypto where the private key stays on a device that is not connected to the internet. The opposite is a hot wallet, whose key sits on an online computer or phone.
- Hot walletA hot wallet is a crypto wallet whose private key is stored on a device connected to the internet: a browser extension, a mobile app, a desktop app or an exchange account. It is convenient because it can sign instantly.
- Hardware walletA hardware wallet is a small dedicated device that generates and stores a private key and signs transactions inside itself. Ledger, Trezor and Keystone are well-known brands. The computer prepares the transaction; the device signs it.
- Crypto walletA crypto wallet is software or hardware that holds the keys to your funds on a blockchain. The coins themselves stay on the chain; the wallet keeps the private key that proves they are yours and uses it to sign transactions.
- Browser extension walletA browser extension wallet is a wallet installed in the browser, such as Chrome or Brave. It adds a provider to web pages so dApps can read your address, request a connection and ask for signatures.
- Non-custodial walletA non-custodial, or self-custody, wallet is one where you hold the private keys yourself. No company can freeze, move or lose your funds, and no one can restore access for you if you lose your recovery phrase.
- Watch-only walletA watch-only wallet knows your addresses or public keys but not your private keys. It can show balances, history and incoming payments, and prepare transactions, but it cannot sign them.
- Multichain walletA multichain wallet manages accounts on several blockchains, such as Ethereum, Solana and Bitcoin, from a single recovery phrase. Each chain family gets its own keys and address format, all derived from the same seed.
Keys and signing
- Seed phraseA seed phrase, also called a recovery phrase or mnemonic, is a list of 12 or 24 words that encodes the master secret of a wallet. Every private key and address in the wallet is derived from it, on every chain.
- Private keyA private key is a secret number that controls one address on one blockchain. It produces the signatures that authorise transactions. From it anyone can compute the public key and the address, but not the other way round.
- Wallet addressA wallet address is the public identifier others use to send you funds, derived from your public key. It is safe to share. Formats differ by chain: 0x... on Ethereum and EVM networks, bc1... on Bitcoin, T... on Tron, a base58 string on Solana.
- QR code signingQR code signing is a way to sign a transaction on an offline device without any data link. The unsigned transaction is shown as a QR code on the online computer, scanned by the offline device, signed there, and returned as another QR code.
- Message signingMessage signing is using your private key to sign text rather than a transaction. It moves nothing on the chain. Sites use it to prove you own an address, for example to log in with Sign-In with Ethereum (EIP-4361).
- EIP-712 (typed data)EIP-712 is an Ethereum standard for signing structured data instead of plain text. The request lists named fields, such as a spender, an amount and a deadline, under a domain that names the contract and the chain it is meant for.
- BC-URBC-UR (Uniform Resources, from Blockchain Commons) is a standard for encoding binary data such as transactions, PSBTs and account keys into QR codes. When the data is too large for one code, it is split into an animated sequence of frames.
Security and scams
- Blind signingBlind signing means approving a transaction or message that your wallet cannot show in readable form, only as a hash or raw hexadecimal data. You sign without knowing what it does.
- Token approvalA token approval, or allowance, is a permission you give a smart contract to move up to a set amount of one of your tokens. dApps need it before they can swap or deposit your tokens for you.
- Wallet drainerA wallet drainer is malicious code, usually on a fake or hacked website, that asks your wallet for signatures designed to transfer your assets to the attacker. It is sold as a ready-made kit, which is why drainer sites appear by the thousand.
- Crypto phishingCrypto phishing is any fake site, message, ad or app that imitates a real one to make you reveal your recovery phrase or sign a harmful transaction. Look-alike domains, fake support accounts and sponsored search results are common routes.
- Address poisoningAddress poisoning is a scam in which an attacker sends you a tiny amount, or a fake token transfer, from an address that starts and ends like one you use. The hope is that you will later copy it from your history and send funds to it.
Transactions and DeFi
- Gas feeA gas fee, or network fee, is what you pay the network's validators to include your transaction. It is paid in the chain's own coin (ETH on Ethereum, SOL on Solana, TRX on Tron) and depends on how much work the transaction needs and how busy the network is.
- NonceOn Ethereum and EVM networks, the nonce is the sequence number of a transaction sent from an account: 0 for the first, then 1, 2 and so on. Each nonce can be used only once, and transactions are processed in order.
- dAppA dApp, or decentralized application, is an app, usually a website, whose logic runs in smart contracts on a blockchain. You connect a wallet to it to trade, lend, stake, vote or mint.
- Crypto swapA swap trades one token for another on the same blockchain, through a decentralized exchange or an aggregator that splits the order across several of them. It settles in a single transaction that you sign.
- Crypto bridgeA bridge moves value from one blockchain to another, for example USDC from Ethereum to Solana. Depending on the design, it locks tokens on one side and releases them on the other, or pays you from liquidity already waiting on the destination chain.
- Perpetual futuresPerpetual futures, or perps, are contracts that track the price of an asset without ever expiring. You open a long or short position with margin and optional leverage; a funding rate paid between longs and shorts keeps the contract close to the spot price.
- Token lockerA token locker is a smart contract that holds tokens and releases them only under set conditions: a date, a price or a vesting schedule. Projects use it to lock liquidity pool tokens or team allocations so they cannot be sold early.
Chain by chain
- PSBTA PSBT (Partially Signed Bitcoin Transaction, BIP-174) is the standard format for handing an unsigned Bitcoin transaction from one tool to another. It carries the inputs, the outputs and the data a signer needs, and collects signatures until the transaction is complete.
- Bitcoin OrdinalsOrdinals is a scheme that numbers each satoshi, the smallest unit of bitcoin, so it can be tracked individually. Data inscribed on a satoshi (an image, text, a token) is called an inscription and is often described as a Bitcoin NFT.
- TrustlineOn Stellar and the XRP Ledger, a trustline is your account's agreement to hold a specific asset from a specific issuer, such as USDC. Until you add one, the account cannot receive that asset.
- Memo and destination tagA memo is a short note attached to a payment on Stellar and the Cosmos chains; on the XRP Ledger the same role is played by a number called a destination tag. Exchanges use one shared address for many customers and rely on it to credit the right account.
- IBCIBC (Inter-Blockchain Communication) is the protocol Cosmos chains use to send tokens and messages to each other, over a port and a channel opened between two chains. A token that crosses over appears on the other side under an ibc/... denomination.
- authz grantauthz is a Cosmos SDK module that lets one account (the granter) authorise another (the grantee) to send certain messages on its behalf, within limits and until an expiry date. Auto-compounding services use it to restake rewards for you.