Introduction
Passkey technology promises to revolutionize how we log into our online accounts, but it’s still widely misunderstood. As a digitalization consultant, I’ve often seen that the best security is only effective when users understand how it works. Just as passwords became vulnerable partly due to poor user practices, passkeys could also be compromised if used without understanding their underlying mechanisms.
In this article, I’ve tried to strike a delicate balance: explaining passkeys in an accessible way while covering the technical aspects essential for proper use. My goal is to give you the keys (pun intended 😂) to understanding this new technology without drowning you in overly complex details. Because while passkeys are designed to be simple to use, understanding how they work remains the best guarantee of their effectiveness.
A New Era for Online Security
Traditional passwords have become a real headache: hard to remember, often insecure, and vulnerable to hacking. To address these challenges, a new technology called passkeys (or digital access keys) is emerging to transform how we connect online.
How Does a Passkey Work?
Imagine that each website is a door you need to open. With a traditional password, you have to remember and type a secret code every time you log in. With a passkey, the process is quite different and more secure.
A passkey uses a system of paired mathematical keys. Your device (phone or computer) keeps a secret private key in its built-in password manager (Keychain on macOS, Windows Password Manager, or Google Password Manager on Android). When you first set up a passkey for an online account, the website generates and stores a corresponding public key that will allow it to verify your identity during future logins. These two keys are mathematically linked, but it’s impossible to figure out one from the other.
When you log in, the website sends a mathematical challenge to your device. Your private key solves this challenge, proving that you’re the legitimate account owner, without ever revealing the key itself. It’s like proving you have the right key without ever taking it out of your pocket.
Security Through Physical Possession
The main strength of passkeys lies in their connection to your personal device. Private keys are stored securely in your device and can only be used after you’ve proven your identity, whether through fingerprint, facial recognition, or a secure PIN code.
This approach naturally protects against phishing. Even if a hacker creates a perfect copy of a website, they’ll never be able to access your account because the fake site doesn’t have the legitimate public key needed to create the mathematical challenge. Without the correct public key, the cryptographic system simply can’t work, making any login attempt on a fake site impossible.
Protecting Your Device: The New Priority
Since your device becomes the guardian of your digital access, its security is paramount. A PIN code that’s too simple, like “1234,” would compromise the entire system’s security. Choose a PIN of at least six random digits, or better yet, a proper complex password combined with biometric protection for simpler and faster access.
Your device’s automatic lock and built-in encryption provide essential additional protection. These mechanisms ensure that even if your device is stolen, your passkeys remain inaccessible to malicious individuals.
Logging In From Different Devices
You’ll often want to log into a website from a device that doesn’t have your passkey, such as a new computer or a public device. In this case, the website typically displays a QR code. For users accustomed to traditional passwords, a QR code appearing during a login attempt might seem confusing. However, this step makes sense when you understand that the passkey needed for login is on another device. By scanning this code with your phone that contains the passkey, you can authorize the login on the other device. The QR code contains the information needed for your phone to identify the site and the current login session. Once you confirm your identity on your phone (via fingerprint, facial recognition, or PIN), the passkey solves the cryptographic challenge and authorizes the login on the other device. This method is both convenient and secure: even if the device you’re using is compromised, it will never have access to your passkey, which remains protected on your phone.
Backup and Daily Use
Passkeys aren’t limited to a single device. In the Apple ecosystem, they’re synchronized in a completely encrypted manner across your devices so that even Apple can’t access them1: only your personal devices can access the private keys. Google2 and Microsoft3 also use end-to-end encryption to store passkeys. Microsoft also offers synchronization solutions, though the technical details of its implementation are less transparent. In any case, it’s recommended to have at least two devices configured to access your passkeys to avoid any risk of losing access.
Day-to-day use is simple: when you visit a website, your device simply asks you to confirm your identity through biometrics or PIN. The technical part (the mathematical challenge) happens in the background and remains invisible to the user. No more need to remember or type complex passwords. If you switch devices, your passkeys are automatically synchronized securely.
Toward a More Secure Future
Passkeys represent a natural evolution of digital security. They combine robust mathematical security with a simplified user experience. This technology is already being adopted by major web companies, and it’s likely that in the coming years, we won’t need to remember passwords anymore.
Online security thus becomes a simple daily formality, as natural as unlocking your phone. By understanding how they work and adopting a few basic habits, everyone can already start enjoying this innovation that makes our digital lives both simpler and more secure.
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