Yubico’s Proposed WebAuthn Protocol to Make it Easier to Replace Missing Keys

Yubico is trying to make it easier to replace a lost security key. To that end, the company has developed a new technology called “Asynchronous Remote Key Generation” (ARKG), and has pitched it to the World Wide Web Consortium (W3C) Web Authentication Working Group to ask the organization to recognize ARKG as an official protocol extension. Yubico partnered with the Surrey Centre for Cyber Security to demonstrate the cryptographic strength of the technology, and presented its findings at the ACM CCS conference on November 11.

So how does the proposed protocol work? In plain terms, Yubico’s ARKG tech cryptographically links two security keys. One of those keys can then be used as a primary key to generate public keys on behalf of the other, which becomes the backup.

In practice, that means that the owner of a security key will create two separate public keys every time they use their primary key to create a new account. The website or service would detect that the primary key has been linked to a backup, and would create a key for (and recognize the legitimacy of) that backup even if the user does not have it on hand at the time.

If the user then loses their primary key, they would then be able to switch directly to the security key with minimal disruption. They would simply need to select the “I lost my security key option,” and the service would automatically switch to the backup key and revoke the privileges of the primary key. After that, the backup becomes the primary, and the owner can purchase (and link) a new key to that new primary to repeat the cycle.

The backup private keys are stored on the host server rather than the security key itself, which means that users can set up backups for an unlimited number of services. Yubico acknowledged that interested parties would need to develop universal standards should ARKG become an official protocol extension. They would also need to develop support services, including services that can link two keys, like the YubiKey Manager does for YubiKeys.

Yubico’s proposal would build on its support for FIDO’s WebAuthn standard, which became an official W3C standard in 2019. More recently, the company gave customers a more detailed look at its upcoming biometric security key.