Dan Boneh, a Stanford professor and cryptography pioneer, joins Justin Thaler, a research partner at a16z and expert in cryptographic proof systems, to explore the fascinating world of quantum computing. They dive into the implications of quantum threats on traditional cryptography and the urgent need for adaptation. With anticipated timelines for quantum advancements, they discuss the strategies organizations must employ, zero-knowledge proofs, and the potential resilience of blockchain technologies against quantum challenges while teasing apart the noise from the real advancements.
Quantum computing significantly alters computational capabilities, with concerns about its ability to break classical cryptographic systems like RSA and elliptic curve cryptography.
The urgency for post-quantum cryptographic systems is underscored by NIST's expected deprecation of classical algorithms by 2035, necessitating timely transitions for builders.
Lattice-based cryptography is emerging as a promising solution for post-quantum security, emphasizing the need for thorough evaluation and research into robust alternatives.
Deep dives
Understanding Quantum Computing and Its Implications for Cryptography
Quantum computing represents a significant shift in computational capabilities, allowing for the resolution of problems that classical computers can't solve efficiently. The core idea stems from Richard Feynman’s insight that quantum experiments can perform computations beyond classical limitations. Notably, Shor's algorithm can efficiently factor large numbers and solve discrete logarithms, which are foundational for modern encryption schemes. The potential for quantum computers to break classic cryptographic systems sparks concern, especially in sectors relying on secure communications and transactions.
The Transition to Post-Quantum Cryptography
As the potential for quantum computing advances, the need for post-quantum cryptographic systems becomes critical, especially for digital signatures and encryption. The National Institute of Standards and Technology (NIST) is working to phase out classical systems like RSA and elliptic curve cryptography in favor of quantum-resistant alternatives. Timelines suggest urgency, with some algorithms expected to be deprecated by 2035, underscoring the necessity for builders to transition to quantum-resistant systems. This evolution emphasizes both the challenges of adopting new technologies and the potential costs associated with transitioning to systems that may initially require more resources.
Significant Challenges with Upgrading Systems
Transitioning to post-quantum cryptography presents unique challenges for blockchain technologies, which must adapt without compromising security or performance. Digital signatures require careful consideration as switching to new signature algorithms can lead to larger data footprints, impacting system efficiency and decentralization. Communities within the blockchain space, notably Bitcoin, face difficulty agreeing on substantial changes, necessitating that any new signature scheme is both secure and sustainable. As these changes loom, lengthy discussions over the timing and execution of transitions will be critical to ensure the integrity of blockchain operations.
Exploring Zero-Knowledge Proofs (ZKPs) in the Quantum Era
Zero-knowledge proofs are pivotal for privacy and data integrity in blockchain systems and will require scrutiny as quantum computing evolves. Current ZKP systems may not need immediate replacement since their privacy properties remain intact even against future quantum attacks. However, the soundness of these proofs must be rigorously evaluated to guard against evolving quantum capabilities. As a result, builders in this space can afford to delay switching to fully post-quantum secure ZKPs until substantial advancements underscore the necessity.
Lattice-Based Cryptography: A Viable Path Forward
Lattice-based cryptography emerges as a promising alternative for post-quantum systems due to its mathematical robustness and difficulty in being solved by quantum algorithms. The consensus is shifting toward using lattice structures as the foundational problems for building secure cryptographic primitives that remain resistant to quantum attacks. Recent research highlights advancements in lattice-based folding schemes, potentially matching the efficiency of current elliptic curve systems while being secure against quantum capabilities. As the community expands research into these areas, ongoing exploration and validation will be crucial to ensure that new systems can effectively replace older, vulnerable methodologies.
Preparedness and the Future of Cryptography
While quantum computing poses imminent threats to existing cryptographic systems, an overreaction can lead to rushed implementations that jeopardize security. Builders should prepare for a future where quantum computers are prevalent, assessing the costs versus benefits of transitioning to post-quantum alternatives. A considered approach to adopting new technologies—favoring stability and proven methodologies—will yield the best outcomes for system security. The emphasis should be on preparing robust frameworks and understanding when to make necessary shifts, ensuring that the responses are adequately timed and informed by ongoing research.
This episode is all about quantum computing -- explaining what it is, how it works, what's hype vs. reality, and how to prepare for it/ what builders should do.
Specifically, we cover:
What quantum computing is and isn't, and what people are really talking about when they worry about a quantum computer that can break cryptographic systems that are not secure against quantum attacks.
When is it happening/ what are the "timelines" for quantum computing becoming a reality -- or rather, when could we have a cryptographically relevant quantum computer -- how many years away are we? and when are the U.S. government's deadlines/ NIST standards for post-quantum cryptography?
How will different types of cryptography be affected, or not? What are different approaches and tradeoffs?
Where does quantum computing and post-quantum crypto apply to blockchains -- which by and large rely on signatures, not encryption, so may be more quantum-resistant in many ways (and not in others)...
As always, we tease apart the signal vs. the noise in recent "science-by-press release" corporate quantum-computing milestone announcements.
We also help answer questions on when do builders need to plan their switch to a post-quantum crypto world, what pitfalls to avoid there (hint: bugs! software upgrades!).
Finally, we briefly cover different approaches to post-quantum crypto; and also dig deeper on zero-knowledge/ succinct-proof systems and how they relate to post-quantum crypto.
Our expert guests are:
Dan Boneh, Stanford University professor and applied cryptography expert and pioneer; also Senior Research Advisor to a16z crypto;
Justin Thaler, research partner at a16z, professor at Georgetown, and longtime expert and pioneer in interactive and ZK proof systems.
"Q-Day Clock" from Project Eleven -- public dashboard to visually track timeline for quantum computing to reach cryptographically relevant capabilities and break widely used encryption algorithms
As a reminder, none of this is investment, business, legal, or tax advice; please see a16z.com/disclosures for more important information including a link to our investments.
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