What Is Passkey? The Future of Authentication

Table of contents

The Problem with Passwords

Let’s be honest: passwords are fundamentally broken.

Think about it:

• You need a different password for every service (but who actually does that?)
• They must be complex enough to resist brute-force attacks (but simple enough to remember)
• You need to change them regularly (but not reuse old ones)
• You need two-factor authentication as backup (adding even more friction)
• They can be phished, leaked, guessed, or stolen

The uncomfortable truth: even if you follow all the best practices, passwords can still be compromised. A data breach at a service you trust can expose your credentials. A convincing phishing email can trick you into typing your password on a fake login page. A keylogger on a compromised computer can capture everything you type.

Passwords place the burden of security on you, the user. And humans, frankly, aren’t very good at managing dozens of complex, unique passwords.

What Is a Passkey?

A passkey is a modern authentication method that replaces passwords with cryptographic key pairs. Instead of typing a password, you authenticate using a device you already own—your phone, laptop, or security key.

Here’s the magic: passkeys are phishing-resistant, impossible to guess, and you never need to remember them.

But how does it work?

The Core Concept: Public Key Cryptography

Passkeys rely on battle-tested technology called public key cryptography, the same foundation that secures online banking, encrypted messaging, and HTTPS connections.

Here’s the simple version:

When you create a passkey for a website, your device generates two linked keys:

1. A private key – stored securely on your device, never leaves it, never shared
2. A public key – sent to the website and stored in their database

These keys are mathematically linked: something encrypted with the public key can only be decrypted with the private key.

Think of it like a lock and key:

• The website has the lock (public key)
• You have the key (private key)
• Only your key can unlock that specific lock

When you log in, the website sends a challenge (essentially saying “prove you have the private key”). Your device uses the private key to sign that challenge and sends back the proof. The website verifies it using the public key, and you’re logged in.

No password transmitted. No shared secret. No phishing possible.

How Passkeys Work in Practice

Let’s look at what actually happens when you use a passkey.

Creating a Passkey (Registration)

1. You visit a website (say, example.com) and choose to create an account
2. Instead of typing a password, you click “Create a passkey”
3. Your device (phone, laptop, security key) generates a unique key pair specifically for example.com
4. The private key stays locked on your device (protected by biometrics or a PIN)
5. The public key is sent to example.com and stored in their database
6. Done. You’re registered.

Logging In with a Passkey

1. You visit example.com and click “Sign in with passkey”
2. The website sends a challenge (a random piece of data) to your device
3. Your device prompts for verification: Face ID, fingerprint, PIN, or device unlock
4. Once verified, your device signs the challenge with the private key
5. The signed response is sent back to the website
6. The website verifies the signature using the stored public key
7. You’re logged in. No password typed. No SMS code needed.

The entire process takes seconds, often faster than typing a password.

Why Passkeys Are More Secure

Passkeys solve the fundamental security problems that plague passwords.

1. Phishing-Resistant

This is the killer feature.

With passwords, if a fake login page looks convincing enough, you might type your password into it. Game over.

With passkeys, phishing is mathematically impossible.

Here’s why: when your device creates a passkey, it binds it to the exact domain (like example.com). When you try to log in, your device checks the domain. If you’re on example.com, it works. If you’re on examp1e.com (notice the “1” instead of “l”), your device won’t even offer the passkey.

No convincing design, fake email, or social engineering can bypass this. The cryptography doesn’t care how legitimate the fake site looks.

2. Impossible to Guess and Unbreakable

Passwords can be:

• Guessed (people use predictable patterns)
• Brute-forced (trying millions of combinations)
• Cracked (if the hash is weak)

Passkeys use 256-bit cryptographic keys. To put that in perspective: there are more possible keys than atoms in the observable universe. Brute force isn’t just impractical—it’s impossible.

3. Immune to Data Breaches

When a service gets hacked and their database leaks, your passkey doesn’t matter.

Why? Because the website only stores your public key. Even if attackers steal it, they can’t use it to log in as you. They’d need the private key, which is on your device and never transmitted.

Compare this to passwords: when LinkedIn, Dropbox, or Adobe get breached, millions of password hashes leak. Even with hashing, weak passwords can be cracked.

4. No Reuse Problem

Each passkey is unique to the website. You can’t “reuse” a passkey across multiple services (the cryptography won’t allow it). This eliminates the classic password reuse vulnerability where a single breach compromises multiple accounts.

5. No Human Memory Required

You don’t need to remember, type, or manage anything. Your device handles it all. This removes the weakest link in security: human behavior.

The User Experience: Faster and Easier

The security improvements matter, but passkeys also make logging in dramatically easier.

Gone:

• Typing complex passwords on mobile keyboards
• Resetting forgotten passwords via email
• Waiting for SMS codes (which sometimes never arrive)
• Managing authenticator app tokens
• Answering security questions (“What was your first pet’s name?”)

Instead:

• Click “Sign in”
• Unlock with your face, fingerprint, or device PIN
• Done

It’s the same gesture you use dozens of times a day to unlock your phone—now it logs you in everywhere.

Current Adoption: Where Can You Use Passkeys Today?

Passkeys aren’t science fiction. They’re here, they’re standardized, and major platforms already support them.

Services Supporting Passkeys

As of 2025, you can use passkeys on:

• Google (Gmail, YouTube, Google Workspace)
• Apple (Apple ID, iCloud)
• Microsoft (Microsoft accounts, Azure)
• GitHub (developer accounts)
• PayPal (payments and accounts)
• Amazon (shopping accounts - rolling out)
• Cloudflare (security and infrastructure)
• And hundreds more services adding support every month

Devices Supporting Passkeys

Passkeys work on:

• iOS 16+ and iPadOS 16+ (Face ID, Touch ID)
• macOS Ventura+ (Touch ID, password)
• Android 9+ (fingerprint, face unlock, PIN)
• Windows 10+ (Windows Hello, security keys)
• Chrome, Safari, Edge, Firefox (all major browsers)
• Hardware security keys (YubiKey, Google Titan, etc.)

The Technology Behind Passkeys: WebAuthn and FIDO2

If you’re curious about the technical foundations (you don’t need to know this to use passkeys, but it’s interesting):

Passkeys are built on two open standards:

1. WebAuthn (Web Authentication API) – a W3C standard that defines how websites interact with authenticators
2. FIDO2 (Fast Identity Online 2) – a set of protocols for passwordless authentication

These standards are backed by the FIDO Alliance, a consortium including Apple, Google, Microsoft, Meta, Amazon, and others. This cross-industry collaboration ensures passkeys work consistently across all platforms.

The cryptography uses:

• Elliptic Curve Cryptography (ECC) for key generation
• ECDSA or EdDSA for digital signatures
• Challenge-response authentication to prove key possession

When you create a passkey, the private key is protected by your device’s Secure Enclave (Apple), Trusted Execution Environment (Android), or TPM (Windows)—hardware-isolated security chips that make key extraction virtually impossible.

The Future: A Passwordless World

Passwords have been with us since the 1960s—a security model designed for mainframes, not the modern internet.

Passkeys represent a fundamental shift: from secrets you know (and can forget, leak, or mistype) to cryptographic proof of what you possess (secured by your devices).

What’s next?

• More services adopting passkeys (expect near-universal support by 2026-2027)
• Improved cross-platform sync (easier passkey portability)
• Enterprise and government adoption (compliant passwordless auth)
• Integration with identity verification (combining passkeys with ID verification)

For users, this means:

• Fewer passwords to remember (eventually, none)
• Faster logins (Face ID and you’re in)
• Better security (phishing and breaches become far less effective)

For developers, this means:

• Simpler authentication (no password hashing, rotation policies, or reset flows)
• Fewer support tickets (“I forgot my password” becomes rare)
• Stronger security posture (fewer credential-related breaches)

Building for the Passwordless Future

At Nekolab, we’re closely tracking the evolution of authentication technologies. As we develop Clefi, our compliance-first password manager, we’re designing with passkey support in mind from day one.

Because here’s the thing: even in a passwordless future, you’ll still need a secure way to manage your passkeys, sync them across devices, and maintain access to legacy systems that haven’t upgraded yet.

The future isn’t “passwords vs. passkeys”, it’s a hybrid where both coexist, with passkeys gradually becoming the default.

If you’re interested in Clefi’s development or want to discuss authentication, security, or the future of passwordless tech, reach out at andrea@nekolab.fr, visit clefi.app, or follow the blog.

Start Using Passkeys Today

Don’t wait for the future: passkeys are here now.

Pick a service you use frequently (Google, GitHub, PayPal) and set up a passkey this week. Experience how much faster and easier it is. Then gradually add more.

Your future self will thank you, no more password resets, no more phishing anxiety, just frictionless, secure authentication.

Welcome to the passwordless future. 🔐

Want to learn more about security, privacy, and building in public? Subscribe to the blog or reach out at andrea@nekolab.fr. Let’s build a safer web together.