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Explainer

Passkeys explained: the beginning of the end for passwords

Published 28 July 2026 · 7 min read · by the Celestial Security Team

Passwords have been the internet's front door for fifty years — and its weakest point for almost as long. Passkeys are the most promising replacement we've seen. Here's how they work and why they matter.

What is a passkey?

A passkey is a pair of cryptographic keys. The private key stays securely on your device (or in your encrypted vault); the public key is registered with the website. To sign in, your device proves it holds the private key by signing a challenge — without ever revealing the key itself.

Why passkeys are safer

• Nothing to steal from the server. The site only stores a public key, which is useless to an attacker.
• Phishing-resistant. A passkey is bound to the exact website domain, so a fake login page simply can't use it.
• No reuse. Every passkey is unique to one service. A leak on one site can't affect another.
• Nothing to type. You approve with Face ID, a fingerprint, or a PIN — fast and impossible to shoulder-surf.

How Celestial handles passkeys

Celestial can create, store and autofill passkeys, syncing the encrypted private keys across all your devices with the same zero-knowledge protection as the rest of your vault. That means you get the security of passkeys and the freedom to use them on any device — not just one phone.

Passkeys solve authentication. A zero-knowledge vault solves storing and syncing them safely. Together, they're the future of login.

Do passwords disappear overnight?

No. Adoption is growing quickly, but many sites still rely on passwords, and some never fully migrate. That's exactly why a good vault matters: it manages your passkeys, your remaining passwords, and your 2FA codes together, so you're covered everywhere during the long transition.

Getting started

Next time a site offers to "create a passkey", say yes — then let Celestial store it. You'll wonder how you ever tolerated typing passwords at all.