What Is Passwordless Authentication and How Does It Work?

What Is Passwordless Authentication and How Does It Work?

Passwordless authentication is a sign-in method that verifies a user's identity without requiring them to enter a password. Instead, it relies on something the user has or is — a registered device, a biometric scan, or a security key — using cryptographic keys that never leave that device.

It matters because most identity attacks depend on a password existing somewhere it can be stolen, guessed, or phished. Removing the password removes that target entirely, which is why passwordless authentication is increasingly treated as the end goal of identity security, not just an upgrade to MFA.

Why Is Passwordless Authentication Gaining Ground So Quickly?

The shift isn't incremental — it's structural. Gartner projects that by 2025, over 50% of workforce authentication transactions and more than 20% of customer logins will be passwordless.

The practical results from organisations that have made the switch are consistent. Organisations that have completed passwordless rollouts consistently report 60–80% reductions in help desk password reset volumes and faster sign-in experiences across endpoints and applications. In one documented case, a financial services firm that moved privileged users from smart cards to Windows Hello and FIDO2 keys saw helpdesk password resets drop by 75%, with improved audit compliance through phishing-resistant authentication logs.

The security case is just as direct. Stolen credentials drive roughly 22% of breaches in 2025, and shrinking the credential attack surface through passwordless logins is one of the clearest defences against this. A password that doesn't exist can't be reused, leaked in a database breach, or entered into a fake login page.

This is also reflected in real adoption behaviour. In a 2024 survey commissioned by the FIDO Alliance, 53% of people reported enabling passkeys on at least one of their accounts, with 22% enabling them on every account they possibly can — a notable shift for a technology that, a few years ago, was largely confined to enterprise pilots.

What Do Standards Bodies Say About Passwordless Authentication?

Passwordless authentication isn't just a vendor trend — it's becoming the reference point in updated security standards. NIST SP 800-63-4, the 2025 update to the Digital Identity Guidelines, emphasises stronger phishing-resistant authentication methods like passkeys, with FIDO2 forming the standard and hardware security keys recognised as the highest-assurance authenticator.

This matters for organisations beyond government contractors. When a standards body raises the bar on what counts as strong authentication, audits and compliance frameworks that reference NIST guidance tend to follow. Passwordless adoption is increasingly tied to enhanced regulatory compliance with phishing-resistant standards under NIST 800-63B and the CISA Zero Trust Maturity Model.

The connection to conditional access policies is direct. A conditional access policy can require a specific authentication strength — including phishing-resistant methods — before granting access to sensitive applications. Without passwordless or FIDO2-based options available to users, that requirement either can't be enforced or pushes users toward weaker fallback methods.

Moving toward passwordless authentication touches identity providers, device management, and conditional access policies all at once — which is why most organisations underestimate the planning involved. Our SaaS Security for Microsoft 365 and Google Workspace course covers how to plan and roll out passwordless authentication across a real Microsoft 365 and Google Workspace environment.

How Should Organisations Roll Out Passwordless Authentication Without Breaking Legacy Apps?

The most common obstacle isn't user resistance — it's the applications themselves. Many business applications still use outdated protocols such as LDAP or SAML, which were built for traditional password-based systems and struggle to support passwordless ecosystems. This means a rollout has to start with an inventory of which applications can support modern authentication standards and which can't, rather than assuming every app will work the same way.

Privileged accounts are the logical starting point, for the same reason they're prioritised in MFA rollouts. These accounts carry the highest risk if compromised, and the financial services example mentioned earlier shows the pattern clearly: moving administrators from smart cards to FIDO2 keys cut helpdesk resets dramatically while improving the audit trail at the same time.

Recovery planning needs to happen before rollout, not after the first lost device. Poor recovery experiences undermine authentication modernisation initiatives — if a user loses a phone or security key and the recovery process is slow or insecure, it creates pressure to fall back to passwords, which defeats the purpose. A well-designed recovery path usually involves a secondary registered method and a verified identity check, not a simple password reset.

Running a pilot with a smaller group before full rollout mirrors the approach used for MFA and conditional access. A field study at a mid-sized IT company found that to fully unfold the security benefits of FIDO2, security keys need to be adopted completely, with password and OTP fallback disabled entirely — partial adoption, where passwords remain available as a fallback, doesn't deliver the same security improvement, because attackers will simply target the weaker option that's still active.

Coordinating with conditional access policies is the final piece. Once passwordless methods are available, conditional access policies can require them specifically for sensitive applications or privileged roles — moving from "MFA required" to "phishing-resistant authentication required" for the accounts where it matters most.

Frequently Asked Questions

Is passwordless authentication the same as using a passkey?

Not quite — a passkey is one specific implementation of passwordless authentication. Passwordless authentication is the broader category, covering any method that doesn't require a password: biometrics, hardware security keys, magic links, or passkeys. Passkeys are built on FIDO2 specifications and use standard public-key cryptography to provide phishing-resistant authentication, replacing password-only logins with a faster, more secure sign-in.

Other passwordless methods, like one-time codes sent by email or SMS-based magic links, are weaker than passkeys because they can still be intercepted or phished. When an organisation says it's "going passwordless," it's worth clarifying which method is being deployed, since the security benefit varies significantly between them.

What happens if an employee loses the device used for passwordless sign-in?

This is the scenario every rollout plan needs to account for before it happens. Most enterprise passwordless setups allow a user to register more than one authenticator — for example, a hardware key and a phone-based authenticator — so losing one doesn't lock them out entirely.

If a user loses their only registered method, recovery typically requires identity verification through a separate channel — often involving IT or HR confirming the person's identity before a new authenticator is issued. This process should be documented and tested before rollout, since an unclear or rushed recovery process is one of the most common reasons organisations revert to password fallbacks after a passwordless rollout begins.

Moving away from passwords touches identity providers, device management, and conditional access all at once — and getting the sequencing wrong is where most rollouts stall. Our SaaS Security for Microsoft 365 and Google Workspace course covers how to plan a passwordless rollout that works with your existing conditional access setup, not around it.