How do you test cross-device authentication for passkeys?

Cross-device authentication is a critical feature of passkeys, ensuring users can seamlessly authenticate across various devices. Here’s how to effectively test cross-device authentication scenarios:

• Mobile to Desktop: Test scenarios where a passkey created on a mobile device is used to log in on a desktop browser.
• Desktop to Mobile: Verify authentication using a passkey created on a desktop for access on a mobile device.
• Platform-Specific Flows: Test transitions between platforms, such as Android to macOS or iOS to Windows.

• QR Code Authentication: Ensure QR codes for cross-device authentication are scanned and processed correctly.
• Account Linking: Verify that accounts can be seamlessly accessed across devices without requiring re-registration.

• Device Variations: Include a range of devices in your testing matrix, such as older and newer models.
• Browser Interoperability: Ensure passkeys work across all major browsers on each device type.

• Unavailable Passkeys: Test scenarios where a passkey is unavailable on the current device and ensure users can fall back to other authentication methods.
• Alternative Flows: Verify the smooth execution of fallback options, such as OTPs or passwords.

• Data Integrity: Ensure that cross-device authentication protects user credentials and does not expose sensitive data.
• Man-in-the-Middle (MitM) Attacks: Test for potential vulnerabilities during cross-device communication.

• Clear Instructions: Check that users are guided effectively through cross-device authentication processes.
• Error Feedback: Verify that errors are communicated clearly, helping users resolve issues quickly.

By rigorously testing these scenarios, you can deliver a robust and seamless cross-device authentication experience for passkey users.