Seed Phrases and Wallet Security: The Rules That Prevent 99% of Losses

Crypto is not stored "in" a wallet — it lives on the blockchain. Your wallet stores keys. The 12 or 24-word seed phrase (BIP-39) is the master key that regenerates every key your wallet will ever create. Whoever has the phrase has the coins; whoever loses it loses the coins. There is no password reset.

Hot vs. cold wallets

• Hot wallet (phone/browser): convenient, always online — fine for small, active balances.
• Hardware wallet (cold): keys never touch the internet — the standard for meaningful holdings.
• Exchange account: not your wallet at all. "Not your keys, not your coins."

The iron rules

• Never type your seed phrase into any website or app — no legitimate service ever asks.
• No photos, no cloud notes, no email. Paper or stamped steel, stored offline.
• Write it down by hand, twice, in two separate physical locations.
• Beware "support" DMs and look-alike sites — phishing is the #1 attack.
• Send a small test amount first when moving to a new address.
• Plan inheritance: someone you trust must be able to recover access if something happens to you.

Approval phishing

A modern drain needs no seed phrase: trick you into signing a token approval, and the attacker can move your approved tokens at will. Review what sites you connect to, revoke stale approvals periodically, and use a separate "burner" wallet for new dApps.