<?xml version="1.0" encoding="UTF-8"?><rss version="2.0"><channel><title>Héctor Masip Ardevol: Writing</title><description>Notes on zero-knowledge proofs, cryptography and the math behind them.</description><link>https://hecmas.github.io/</link><item><title>STIR+</title><link>https://hecmas.github.io/writing/stir/</link><guid isPermaLink="true">https://hecmas.github.io/writing/stir/</guid><description>Notes on STIR-style proximity testing, where each round cuts the degree by k but only halves the domain: the construction, how to handle repeated queries, and round-by-round soundness.</description><pubDate>Fri, 28 Aug 2026 00:00:00 GMT</pubDate></item><item><title>DEEP Quotients over the Base Field</title><link>https://hecmas.github.io/writing/deep-quotients-over-the-base-field/</link><guid isPermaLink="true">https://hecmas.github.io/writing/deep-quotients-over-the-base-field/</guid><description>Keep STARK DEEP quotients over the base field by dividing by the minimal polynomial of the out-of-domain point instead of X − z, so base-field columns never touch extension-field arithmetic.</description><pubDate>Thu, 27 Aug 2026 00:00:00 GMT</pubDate></item><item><title>Fast OOD Evaluation</title><link>https://hecmas.github.io/writing/fast-ood-evaluation/</link><guid isPermaLink="true">https://hecmas.github.io/writing/fast-ood-evaluation/</guid><description>Computing a STARK&apos;s out-of-domain evaluations quickly with barycentric interpolation over the trace subgroup.</description><pubDate>Wed, 26 Aug 2026 00:00:00 GMT</pubDate></item><item><title>How ZisK Enforces Cross-Component Interaction with Arguments</title><link>https://hecmas.github.io/writing/how-zisk-enforces-cross-component-interaction-with-arguments/</link><guid isPermaLink="true">https://hecmas.github.io/writing/how-zisk-enforces-cross-component-interaction-with-arguments/</guid><description>How ZisK&apos;s components (CPU, memory, ALU…) stay consistent: cross-AIR arguments reduced to sumchecks via LogUp, with each component&apos;s partial sums combined through proof aggregation.</description><pubDate>Thu, 05 Feb 2026 00:00:00 GMT</pubDate></item><item><title>On Constraint Satisfiability</title><link>https://hecmas.github.io/writing/on-constraint-satisfiability/</link><guid isPermaLink="true">https://hecmas.github.io/writing/on-constraint-satisfiability/</guid><description>Proving STARK constraints that only hold on part of the trace (boundaries, periodic rows, row selectors) by picking subdomains with sparse vanishing polynomials instead of adding selector columns.</description><pubDate>Mon, 12 Jan 2026 00:00:00 GMT</pubDate></item><item><title>Secure Challenge Derivation in ZisK</title><link>https://hecmas.github.io/writing/secure-challenge-derivation-in-zisk/</link><guid isPermaLink="true">https://hecmas.github.io/writing/secure-challenge-derivation-in-zisk/</guid><description>How ZisK lets many provers agree on a single Fiat–Shamir challenge: accumulate their commitments with LtHash, a lattice-based multiset hash whose security reduces to SIS.</description><pubDate>Wed, 20 Aug 2025 00:00:00 GMT</pubDate></item><item><title>Elliptic Curves over Goldilocks</title><link>https://hecmas.github.io/writing/elliptic-curves-over-goldilocks/</link><guid isPermaLink="true">https://hecmas.github.io/writing/elliptic-curves-over-goldilocks/</guid><description>Building prime-order elliptic curves over a quintic extension of Goldilocks with 128-bit security and efficient hash-to-curve: EcGFp5 and EcMasFp5.</description><pubDate>Mon, 24 Feb 2025 00:00:00 GMT</pubDate></item><item><title>Overwrite Mode in Sponge-Based Permutations</title><link>https://hecmas.github.io/writing/overwrite-mode-in-sponge-based-permutations/</link><guid isPermaLink="true">https://hecmas.github.io/writing/overwrite-mode-in-sponge-based-permutations/</guid><description>Why the Polygon zkEVM&apos;s twist on Poseidon&apos;s overwrite mode, which reroutes outputs between permutation calls, is exactly as safe as the standard construction.</description><pubDate>Fri, 03 Nov 2023 00:00:00 GMT</pubDate></item><item><title>Computing the Optimal Ate Pairing over the BLS12-381 Curve</title><link>https://hecmas.github.io/writing/computing-the-optimal-ate-pairing-over-the-bls12-381-curve/</link><guid isPermaLink="true">https://hecmas.github.io/writing/computing-the-optimal-ate-pairing-over-the-bls12-381-curve/</guid><description>A computation-first walkthrough of the optimal Ate pairing on BLS12-381: the extension-field tower, line equations, final exponentiation and cyclotomic tricks behind our zkASM implementation.</description><pubDate>Fri, 19 May 2023 00:00:00 GMT</pubDate></item><item><title>Computing the Optimal Ate Pairing over the BN254 Curve</title><link>https://hecmas.github.io/writing/computing-the-optimal-ate-pairing-over-the-bn254-curve/</link><guid isPermaLink="true">https://hecmas.github.io/writing/computing-the-optimal-ate-pairing-over-the-bn254-curve/</guid><description>The optimal Ate pairing on BN254, step by step: twist, line equations, the Miller loop&apos;s last two lines, final exponentiation and Frobenius shortcuts, as implemented in the Polygon zkEVM.</description><pubDate>Wed, 05 Apr 2023 00:00:00 GMT</pubDate></item><item><title>Books for Cryptography and Blockchain</title><link>https://hecmas.github.io/writing/books/</link><guid isPermaLink="true">https://hecmas.github.io/writing/books/</guid><description>Learning cutting-edge research areas through books.</description><pubDate>Fri, 14 Oct 2022 00:00:00 GMT</pubDate></item><item><title>Degree Adjustment in SNARKs</title><link>https://hecmas.github.io/writing/snark-degree/</link><guid isPermaLink="true">https://hecmas.github.io/writing/snark-degree/</guid><description>On adjusting the degree of SNARK-related polynomials to fit our needs, and why the randomness matters.</description><pubDate>Wed, 12 Oct 2022 00:00:00 GMT</pubDate></item></channel></rss>