Abstract. We introduce Coral, a system for proving in zero- knowledge that a committed byte stream corresponds to a structured object in accordance to a Context Free Grammar. Once a prover establishes the validity of the parsed object with Coral, they can selectively prove facts about the object—such as fields in Web API responses or in JSON Web Tokens—–to third parties or blockchains. Coral reduces the problem of correct parsing to a few simple checks over a left-child right-sibling tree and introduces a novel segmented memory abstraction that unifies and extends prior constructions for RAM in zkSNARKs. Our implementation of Coral runs on a standard laptop, and non-interactively proves the parsing of real Web responses (JSON) and files (TOML and C) in seconds. The resulting proofs are small and cheap to verify.
Coral: Fast Succinct Non-Interactive Zero-Knowledge CFG Proofs (Sebastian Angel, Sofía Celi, Elizabeth Margolin, Pratyush Mishra, Martin Sander, Jess Woods) ia.cr/2025/1420
05.08.2025 00:01 — 👍 7 🔁 3 💬 0 📌 1
IACR News item: 28 July 2025
We'll be receiving the Crypto 2010 Test-of-Time award for our RSA-768 factorization. iacr.org/news/item/26... ❤️
It's award year for factoring!
07.08.2025 15:10 — 👍 4 🔁 2 💬 0 📌 0
A Fiat–Shamir Transformation From Duplex Sponges
We analyze a variant of the Fiat–Shamir transformation based on an ideal permutation. The transformation relies on the popular duplex sponge paradigm, and minimizes the number of calls to the permutat...
We updated our paper on Fiat-Shamir!
We now take a closer look at the gap between what symmetric cryptography has focused on for over 10 years (indifferentiability) and what is actually needed for the soundness of ZKPs and SNARKs (something stronger!).
eprint.iacr.org/2025/536
15.07.2025 06:08 — 👍 15 🔁 5 💬 2 📌 0
YouTube video by TCS+
TCS+ Talk: Tom Gur (Cambridge)
Highly recommend Tom Gur (@tomgur.bsky.social)'s TCS+ talk on the Zero-Knowledge PCP theorem his coauthors and he obtained. Very clear introduction to ZK, to PCPs, and (as an aside) to the unexpected timeline of a research project.
youtu.be/bO6NT0XIAWE @tcsplus.bsky.social
14.05.2025 12:23 — 👍 24 🔁 2 💬 2 📌 0
PQ-OPRF table
This is cool heimberger.xyz/oprfs.html
08.05.2025 07:52 — 👍 14 🔁 6 💬 0 📌 0
New accepted paper at Crypto 2025:
"On Knowledge-Soundness of Plonk in ROM from Falsifiable Assumptions" (Helger Lipmaa, Roberto Parisella, Janno Siim), with ex-students Roberto and @jannosiim.bsky.social (Janno is also now a colleague)
05.05.2025 12:15 — 👍 7 🔁 2 💬 0 📌 1
Just joined! Heard a lot of cryptographers moved here
05.04.2025 16:24 — 👍 3 🔁 0 💬 0 📌 0
