Software vs. Hardware Passkeys: What’s the Difference?

Last updated on February 18, 2025

Software and hardware passkeys are two types of passkeys that provide secure, passwordless login, but they come with significant differences in how they function and the level of security they offer. Understanding these differences will help you make an informed decision about which type of passkey solution best suits your needs.

Hardware Passkeys vs. Software Passkeys: What’s the Difference?

The main difference between hardware-bound and software-bound passkeys is whether they can be synced across devices. Hardware-bound passkey’s private key is stored on a physical security key (such as a YubiKey) or in a device’s Trusted Platform Module (TPM) and cannot be synchronized across other devices nor can it be stored in the cloud. In contrast, the software-bound passkey’s private key is stored on a device’s operating system and can be synced through the cloud, allowing it to be shared across devices.

However, there are many more differences between these two passkey types. Below, we outline a comprehensive comparison.

Software- vs. Hardware-Bound Passkeys: Differences Table

Software Passkeys	Hardware Passkeys
Stored in a device’s OS and synced via cloud services.	Stored on a physical security key (USB, NFC, etc.) or in the Trusted Platform Module.
Can be synchronized and used across multiple devices.	Cannot be copied; bound to the specific device.
Ideal for personal use due to the ease of recovery via cloud backup.	Ideal for enterprises and high-security environments.
Easier to recover if a device is lost, using cloud sync or account recovery methods.	Difficult to recover; requires possession of the specific hardware key.
Lower assurance of security due to the potential vulnerability of cloud services and password managers.	Higher security assurance; the passkey remains on the hardware key and can’t be exported.
Supported by platforms like Apple iCloud Keychain, Google, and Microsoft.	Supported by FIDO2-compatible hardware keys like YubiKey.
Suitable for convenience-focused use cases where security needs are moderate.	Best for users requiring top-tier security with minimal exposure to cloud risks.

Advantages of Software-Bound Passkeys Over Hardware-Bound Passkeys

• Ease of Use and Recovery: With software-bound passkeys, if you lose access to your device, you can easily recover your credentials by restoring them from cloud backups. For instance, if you have an Apple passkey, it can be synced to any Apple device using iCloud.
• Cross-Device Flexibility: Software-bound passkeys can be used on multiple devices without the need to enroll each device separately. This makes logging in across different platforms more seamless, as passkeys are synced through services like iCloud or Google.
• Cost-Effective: Software-bound passkeys are essentially free if you have a compatible smartphone or laptop, as no additional hardware (like security keys) is required.

Advantages of Hardware-Bound Passkeys Over Software-Bound Passkeys

• Top-Notch Security: Hardware-bound passkeys offer the highest level of security because the private key is stored only on the physical security key, and it never leaves that device. This makes it immune to cloud-based attacks and attempts to intercept the encrypted private key in transit.
• Securely Stored Private Key: Since the private key never leaves the security key and cannot be extracted, attackers cannot steal it through remote attacks. This is why hardware-bound passkeys are considered the gold standard for high-security environments.
• Compliance & Control: Enterprises often require strict control over credential management. Hardware-bound passkeys offer this level of control and compliance, particularly when strict security policies are in place. They are ideal for industries that handle sensitive information or need to comply with stringent regulations.
• No Cloud Dependency: Unlike software-bound passkeys, hardware-bound passkeys do not rely on cloud services for storage or syncing, removing the risk of cloud breaches. This makes them preferable for those who distrust cloud services or operate in environments where cloud storage is not feasible.
• Single-Device Passkeys Provide Attestation: Contrary to passkeys synchronized across devices via cloud services that often lack attestation data, making it difficult to verify their origin using standard WebAuthn mechanisms, passkeys stored on single-device FIDO2 security keys usually include attestation, enhancing their security pedigree.

Are Security Keys and Hardware-Bound Passkeys the Same Thing?

No, they are related but not the same thing. In simple terms, security keys are physical devices (like a YubiKey) that can store passkeys, but not all security keys store hardware-bound passkeys by default, and not all passkeys are stored on security keys.

A hardware-bound passkey is a specific type of WebAuthn credential stored on a FIDO security key. The private key never leaves the hardware, making it highly secure.

Security keys can store both discoverable (passkeys) and non-discoverable WebAuthn credentials.

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Software- vs. Hardware-Bound Passkeys: Conclusion

The bottom line is that hardware-bound passkeys offer better security, whereas software-bound passkeys offer better flexibility. This is because software FIDO2 passkeys can be synced across your devices. In contrast, hardware FIDO2 passkeys never leave the device they were generated on, which makes them more secure at the expense of user experience.

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