One-time password (OTP) vs Passkey

Why they differ

A one-time code can be typed into a fake site by mistake; a passkey only answers the real site.

Controls & technical basics

A short code that works for a single login and then expires, sent by text message or shown in an app.

Formal

A code valid for one use or a short time window, worked out by an app or token from a shared secret and the clock or a counter, or sent by SMS - used as the "something you have" factor in MFA.

In plain English

Like a ticket that is torn in half at the door - it gets you in once, and a copy is worth nothing afterwards.

In practice

A lawyer at a Danish law firm logs in to the case system from home; after her password she types the six numbers shown in an app on her phone, which change every 30 seconds.

Why it matters

A stolen password alone no longer gets anyone in, but a code can still be tricked out of a person on a fake page, so phishing-proof methods are stronger.

Passkey

Identity & access

A login without a password, where your device proves who you are with a secret key that never leaves it.

Formal

A credential built on public-key cryptography under the FIDO standards, where the device keeps a private key for each site and signs a fresh challenge with it after the user unlocks with a fingerprint, face or PIN; the site stores only the public key.

In plain English

Like a key that never leaves your key ring and turns only in your own front door - there is no code to say out loud, so a fake door gets nothing from you.

In practice

A case officer at a Danish region opens the staff portal on her work laptop and touches the fingerprint reader when asked to use her passkey; she is in with nothing typed and nothing a fake site could capture.

Why it matters

Passwords get guessed, used again and typed into fake pages; a passkey works only on the real site, and the server holds no shared secret worth stealing.

Shared connections

Authentication Password Authentication factor Credential stuffing Multi-factor authentication