Five years ago, the FIDO2 industry standard emerged as a groundbreaking way to securely access websites. Instead of the conventional password systems we’ve known, it hinged on a sophisticated form of two-factor authentication. Yet, as futuristic as FIDO2 may seem, it still confronts an impending challenge: quantum computing. The advent of quantum technology could make our current cryptographic methods obsolete.
But hope is not lost. In recent times, there has been a race to develop what experts call post-quantum cryptography (PQC) – encryption algorithms designed to withstand quantum-computer attacks. This week, there was a significant announcement from Google. Their researchers unveiled the first-ever quantum-resistant encryption tailored for FIDO2 security keys, the backbone of the FIDO2 system.
For those unfamiliar with FIDO2, one of its prime applications is password-less authentication, referred to as passkeys. Stored in security keys, smartphones, or other gadgets, passkeys offer a fortified barrier against cyber threats. Many platforms have already embraced this innovation, emphasizing its undeniable security advantages.
Elie Bursztein and Fabian Kaczmarczyck from Google remarked on the importance of this proactive approach. “Even though quantum attacks remain a future challenge,” they noted, “implementing these solutions across the internet is an enormous task. Hence, it’s crucial to get started early.” As FIDO incorporates these new standards, there will be a transitional phase as users upgrade their security keys and browsers adjust accordingly.
However, switching to PQC isn’t without risks. Cryptographic stalwarts like RSA have remained unbroken for decades, instilling a sense of trust. Conversely, newer PQC algorithms still need to earn that trust. A recent example underscores this concern: SIKE, a PQC contender, was surprisingly cracked by a standard computer after reaching advanced testing stages at the National Institute of Standards and Technology.
So, Google’s recent offering is both thoughtful and innovative. It merges the trusted elliptic curve digital signature algorithm, vulnerable to quantum attacks, with a promising PQC algorithm, Crystals-Dilithium. Interestingly, Dilithium has made the cut as one of the PQC algorithms endorsed by NIST for digital signatures.
The Google team explained their method, highlighting the two-layered security: “We’ve integrated the tried-and-tested ECDSA signature algorithm with the quantum-resistant Dilithium. This fusion is pivotal, especially considering the unpredictability of newer quantum-resistant solutions.”
Technically, a significant hurdle was tailoring Dilithium to fit within the limited capabilities of standard security keys. Google managed to develop an optimized solution that required a minimal 20 KB memory and maintained an acceptable signature speed. They hinted at future enhancements in signature speed by tapping into hardware acceleration.
Looking ahead, Google aspires to see this quantum-resistant solution become a standard for FIDO2 keys and hopes for its integration into major browsers. This is to ensure that user credentials remain impervious to quantum threats.
Traditional encryption methods, such as RSA, rely on problems that are easy to verify but computationally intensive to solve. For instance, RSA leans heavily on the challenge of factoring large prime numbers. Although current computers struggle with these tasks, Shor’s algorithm presents a quantum way to break such encryptions. Yet, the practical application of this quantum breakthrough is still on the horizon.
While it’s uncertain when quantum computers might outpace their classical counterparts, there’s a consensus on the importance of preparation. As Google’s research indicates, the shift to PQC is inevitable, and it’s wiser to start this transition sooner rather than later.