Security Key

What Is a Security Key?

A security key, also known as a security token, is a physical device used for two-factor authentication (2FA) or multi-factor authentication (MFA) to enhance the security of online accounts and systems. 

Security keys are secondary hardware devices that rely on a primary device, such as a workstation, application or laptop. Security keys require a software integration with the primary device or system as part of its authentication mechanism.They fit into your pocket, can be plugged into any USB port, and operate similarly to smart cards.

YubiKey is a good example of a security key. It offers hardware-based authentication solutions and is resilient against phishing attacks. They work based on the concept of MFA and easily integrate with passwordless authentication solutions such as HYPR. Other popular security key alternatives include Google Titan, Feitian, and Thetis.

Security keys give organizations an additional layer of protection beyond a simple username and password, which are highly vulnerable to credential stuffing, keyloggers, and advanced phishing techniques. 

Research showed that 80% of data breaches were the result of compromised login credentials. Security keys can help prevent data breaches by adding an extra layer of authentication while reducing the risk of unauthorized access to sensitive accounts and systems.  

How Security Keys Work

Most security keys today utilize public key cryptography for authentication. During registration, the public key is associated with the user's account. When the user logs in, the service sends a challenge, and the key signs it with its private key, creating a unique signature. 

The challenge-response mechanism ensures that each authentication request is unique and time-sensitive, making it highly resistant to replay attacks, where an attacker intercepts and maliciously retransmits data similar to a man-in-the-middle attack.

The signature, accompanied by the public key, is then transmitted to the service, initiating the verification process. Upon successful verification, access is granted, thereby guaranteeing that only the verified user with the physical key can successfully finalize the authentication procedure.

But security keys have their disadvantages as well. Let’s take a look at a side-by-side comparison of the pros and cons of using security keys. 

Pros and Cons of Security Keys

Here are a few advantages and disadvantages of using security keys. 



Simple to use and quick to set up 

Costly. For enterprises, maintenance, and renewal can incur more expenses compared to software-based alternatives

Rely on advanced cryptography to generate unique signatures for authentication

Since security keys are small, they can easily get lost, stolen, or damaged 

They do not expose any secret information during authentication. Each transaction generates a unique, one-time signature, thus minimizing the risk of breaches due to credential reuse

The dependence on physical hardware devices means that users must have the key on hand to authenticate at all times. This can be problematic if someone forgets it or if the key malfunctions

Adds an extra security layer to your accounts with 2FA or MFA mechanisms

Using security keys across multiple devices can be inconvenient due to the constant back-and-forth switching

Highly effective against remote attacks. Even if a malicious actor were to gain access to your account credentials, they would still be unable to authenticate without having direct physical access to the security key

Account recovery can be challenging if a security key becomes inoperable or gets lost. This may result in a user being locked out of an account, and the recovery process is more complex than simply resetting a password


What is the Difference Between a Security Key and Passwordless Authentication?

Let’s break down the main differences between security keys and passwordless authentication.

Passwordless Authentication (Based on FIDO Device-Bound Standards)

Security Keys

Multi-factor authentication that uses two independent factors.

Most security keys are single factor authentication. For multi-factor authentication, they need to be used in conjunction with a password or other authenticator, like a FIDO passwordless app.

One factor relies on verifying details that represent, "something you are" such as biometrics in terms of fingerprint or facial recognition for authentication.

The second factor uses the authenticating device (usually mobile phone) as “something you have.”

Relies on the "something you have" factor, where the possession of the access card or token is a requirement for authorization.

Some security keys also have a biometric capability. In these instances, it serves as a “something you are” factor.

Greatly enhanced UX as it is more user-friendly, requiring fewer steps in the login process, and leverages biometric data, which eliminates the need to remember complex passwords and increases security measures

UX is less user-friendly due to the additional authentication step and the need to carry, recall, and occasionally replace an extra device if it goes missing.


Although security keys significantly boost security over passwords and OTP and SMS based MFA methods, they fall short in terms of user experience and cost-benefit ratio compared to passwordless authentication. In fact, research taken from The State of Passwordless Security 2023 showed that 86% of organizations believe that passwordless authentication is essential to both the security and efficiency of their business.

HYPR provides the security level of a hardware key in a convenient passwordless authenticator app, and integrates with security keys for use cases where a mobile device is not suitable. 

Watch Yubico explain how how HYPR and YubiKeys work together in this video:



What happens if I lose my security key?

Losing your security key may temporarily restrict account access. Recovery typically involves using alternative authentication methods or obtaining a replacement key.

Can I use a security key on multiple devices?

Yes, security keys can often be used on multiple devices.

Are security keys secure?

Yes, they are secure. They rely on strong cryptography, offer phishing protection, and require physical possession in order to verify authentication. 


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