lean Ethereum Part 3: Security of PQ SNARKs and an update about the Proximity Prize
Wednesday, 4 March 2026 · 2 min read · Listen to the episode ↗
In this episode of Lean Ethereum, the discussion centers on post-quantum SNARKs and their relevance to Ethereum's future security. Key insights include the recent $1 million proximity prize fostering academic research on proximity gap conjectures, alongside advancements in proof systems like Whirl and Poseidon. Concerns regarding the security of hash-based SNARKs and the need for provable security against emerging threats emphasize the critical importance of robust coding techniques and the implications for blockchain technology.
In this episode of the Lean Ethereum mini-series, host Nico engages with Giacomo Fenzi and Antonio Sanso to explore post-quantum SNARKs and their implications for Ethereum's future. The discussion highlights the recent $1 million proximity prizes from the Ethereum Foundation, which have spurred new academic research on proximity gap conjectures. Giacomo shares insights on protocols like Whirl, Warp, and TensorSwitch, while Antonio discusses his work on Poseidon and Stark, focusing on proof systems.
The conversation emphasizes the mathematical foundations of post-quantum proof systems and the development of Lean VM, which is being tailored for signature aggregation. The new snark technology adopts a modern multilinear approach, raising security concerns about hash-based SNARKs, particularly regarding the balance between security and speed. The proximity app prize aims to enhance confidence in the conjectures used in these systems.
Giacomo, a judge for the proximity prize, notes a surge in research papers addressing the proximity gaps problem, revealing both negative and positive results. The discussion touches on advanced mathematical techniques related to counting fractions and polynomials, highlighting the challenges of detecting corruptions in code words and the implications for security.
A significant breakthrough by Goyal and Gurozwami indicates that certain families of codes, like random linear codes, can achieve security close to capacity, although practical applications in efficient SNARKs are still lacking. The conversation identifies open questions regarding the efficiency of codes exceeding the Johnson bound and encourages further investigation into correlation failures for specific primes.
Concerns are raised about the historical use of Starks with larger primes and the security implications of using 31-bit or 64-bit primes. The discussion also addresses two problems in the Proximity Prize related to Reed-Solomon codes and the relationship between extension field codes and base codes, emphasizing the importance of maintaining a high security threshold in cryptography.
The relevance of security attacks is questioned, particularly if systems maintain over 100 bits of security, with a psychological threshold of at least 128 bits being advocated. The deployment of large systems like Ethereum requires stable parameters, and the importance of provable security is underscored in light of recent attacks.
The episode concludes with open questions regarding the security of post-quantum SNARKs, including the overall security of hash-based SNARKs and the complexities of coding, particularly Reed-Solomon codes. The introduction of the new hash function Poseidon 2 is noted as crucial for system security, alongside ongoing research into mutual credit agreements and the properties of Tuadic fields.
This summary was generated from the episode transcript and can contain mistakes.