Two-Factor Authentication for Crypto Accounts

An exchange account holds a claim on assets rather than the assets themselves, which means whoever can log in and withdraw effectively owns them. Two-factor authentication is what stands between a leaked password and that outcome — but the type you choose changes how much protection you actually get.

SMS is the weakest factor

Codes sent by text depend on your phone number, and a phone number can be moved to an attacker's SIM by social-engineering the mobile operator. This is a SIM-swap, and it has been used repeatedly against people known to hold crypto. Because the same number is often also the account-recovery channel, losing it can hand over the password reset and the second factor at once. Where an exchange allows it, remove the phone number as a recovery method entirely.

Authenticator apps

A time-based one-time password app generates codes on the device from a shared secret, with no network involved, which removes the operator from the picture. It is a large improvement over SMS and is available almost everywhere. Its remaining weakness is phishing: a convincing fake login page can ask for the code and use it within its short validity window. Save the setup secret or recovery codes offline when you enrol, or losing the phone means losing the account.

Security keys are the strongest

A hardware security key using the FIDO2 or WebAuthn standard signs a challenge that is bound to the website's real domain. A phishing site on a lookalike domain cannot produce a valid response, which makes this the only common second factor that resists phishing by design rather than by user vigilance. Register two keys where the exchange permits it, and keep the second somewhere separate.

Lock down withdrawals too

Login protection is only half the job. Add a withdrawal address whitelist so funds can only leave to addresses you pre-approved, and keep any cooling-off period the exchange applies when a new address is added. Set an anti-phishing code if offered, so genuine emails carry a phrase only the exchange knows.