---
title: "What Are Passkeys? Passwordless Sign-In | Bytes Unlimited"
description: "Passkeys replace passwords with cryptographic key pairs stored on your device — phish-resistant by design. The post-password authentication standard, available now across Apple, Google, and Microsoft platforms."
canonical: https://www.bytesunlimited.com/glossary/passkeys/
---

 GLOSSARY · Identity & MFA 

#  Passkeys WebAuthn 

 Phish-resistant authentication that replaces passwords with cryptographic key pairs stored on your device — Face ID or fingerprint unlocks the local key, the website never sees a shared secret to steal. 

## Detailed definition

**Passkeys** are the post-password authentication standard. Built on WebAuthn (FIDO2), they replace the shared-secret model of passwords with public-key cryptography: your device stores a private key locally (unlocked by Face ID, Touch ID, Windows Hello, or a PIN), and the website stores only the matching public key. You can’t be phished because there’s no shared secret to enter into a fake login page — the cryptographic handshake refuses to complete against the wrong domain.

## Why passkeys are a category-changer

Passwords have always been broken. Users reuse them, choose weak ones, and reveal them to convincing phishing pages. [MFA](/glossary/mfa/) helped, but SMS and most TOTP methods are still phishable — a real-time relay attack can intercept the code. Push notifications can be approved by mistake or under “MFA fatigue” pressure.

Passkeys close the phishing hole structurally:

* **No shared secret to steal.** The private key never leaves your device.
* **Origin-bound.** The browser verifies the website’s domain before initiating the handshake. A phishing site at `paypa1.com` cannot complete a passkey login that was registered for `paypal.com`.
* **Local biometric unlock.** Face ID or fingerprint is on-device — the website doesn’t get your biometric.
* **Sync across devices.** Apple, Google, and Microsoft sync passkeys through their respective keychains, so signing in on a new device just works.
* **MFA built in.** A passkey is, by itself, multi-factor — something you have (device + private key) plus something you are (biometric) or know (PIN).

## Where passkey adoption stands

* **Major platforms** — Apple, Google, Microsoft all support passkey storage and sync as of 2024
* **Major sites** — Google, Apple ID, Microsoft, GitHub, AWS, Cloudflare, most banks, increasingly Microsoft 365 and Google Workspace tenants
* **SMB readiness** — most identity providers (Entra ID, Google Workspace, Okta, Duo) now support passkey enrollment alongside legacy MFA methods

The migration pattern is to start by _adding_ passkeys to existing MFA — enrolled users can use either — then gradually phase out weaker methods (SMS first, then TOTP) as adoption grows. Universal passkey rollout is the right end state for most SMBs in the next 1-2 years.

HOW WE HELP

## Related Bytes Unlimited services

* [ Duo MFA Duo multi-factor authentication rollout — app and hardware token enrollment, policy tuning, and end-user training.](/services/duo-mfa/)
* [ Security & Compliance PCI DSS, HIPAA, and general security posture work. Endpoint protection, MFA, awareness training, audit-ready documentation.](/services/security/)

RELATED TERMS

## See also

* [ MFA ](/glossary/mfa/)
* [ SSO ](/glossary/sso/)

AUTHORITATIVE SOURCES

## External references

* [ FIDO Alliance — Passkeys  (opens in new tab) ](https://fidoalliance.org/passkeys/)

##  Need help applying WebAuthn to your business? 

 We've done this kind of work across New York. First conversation is free. 

[ Get In Touch ](/contact/) [ Back to Glossary ](/glossary/)

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