A crypto wallet doesn't actually store your cryptocurrencies — those live on-chain. The wallet stores the private keys (secret strings) that prove your ownership and let you sign transactions.
Fundamental maxim: "Not your keys, not your coins" — if you don't control your private keys (case of exchanges), you don't truly own your cryptos. This is what cost billions to FTX, Mt. Gox, Celsius customers.
Wallet types:
- Hot wallets (online): connected to the internet, convenient but exposed. E.g., MetaMask, Trust Wallet, Phantom (mobile apps/browser extensions). Ideal for small amounts and daily use (DeFi, NFTs, swaps).
- Cold wallets (offline): disconnected from internet, maximum security. E.g., Ledger Nano, Trezor (hardware wallets). Ideal for significant sums (>$1,000) in long-term storage.
- Paper wallet: private keys printed on paper. Ultimate cold storage but fragile (water, fire, loss). Practically obsolete in 2026.
- Multi-sig wallets: require multiple signatures to validate a transaction (e.g., 2-of-3). Used by crypto companies and DAOs.
Seed phrase (recovery phrase): 12 or 24 words that let you regenerate all your private keys. If you lose your hardware wallet, the seed phrase lets you recover everything on a new device. Never:
- Photograph your seed phrase (hacked iCloud = everything lost)
- Type it into a website or non-official app (phishing)
- Share it with anyone (even fake "tech support")
Do: write the seed on paper or metal (Cryptosteel, Billfodl), store securely (safe, bank), ideally in 2-3 copies in different locations.