February - April 2026

8 articles in this issue
Featured Cryptography challenges @KalmarCTF 2026

Cryptography Challenges @KalmarCTF 2026

Minsun shares a high-level overview of the hard cryptography challenges he authored for KalmarCTF 2026, focusing on the broader ideas behind their design and solutions. The post reflects on how subtle randomness failures and algebraic structure can lead to deep vulnerabilities.

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Sum-Check as an Algebraic Tensor Reduction: Part I

Sum-check as an Algebraic Tensor Reduction: Part I

This post introduces algebraic tensor reductions as a unifying framework for understanding recursive proof protocols, using sum-check as the main motivating example. It walks through one recursive step of sum-check, showing how the prover sends a univariate summary, the verifier checks sum consistency, and the original claim is reduced to a smaller claim with one fewer variable. A small bivariate example illustrates how this “peel off one variable, check, then fold with randomness” pattern works concretely. The post sets up the rest of the series, which will introduce the tensor language needed to recover classical sum-check as an algebraic tensor reduction.

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Archetype X zkSecurity - Proof Is in the Pudding: ZK on Bitcoin

In Session 09 of "Proof is in the Pudding," we explore the intersection of zero-knowledge proofs and Bitcoin. We break down Bitcoin's UTXO model and Script limitations, then dive deep into approaches for verifying ZK proofs on Bitcoin, from MPC-based techniques to BitVM's optimistic verification with fraud proofs. We cover timelocks, the statelessness problem and Lamport signatures for state, Taproot, simulated covenants, BitVM 3 with hashlocks and garbled circuits, cut-and-choose security, and witness encryption (BABE).

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KZG vs IPA vs FRI: Picking the Right Polynomial Commitment Scheme

KZG vs IPA vs FRI: Picking the Right Polynomial Commitment Scheme

A practical guide to the trade-offs between KZG, IPA/Halo, and FRI, the three major polynomial commitment scheme families powering modern zero-knowledge proof systems. We compare proof sizes, verification costs, trust assumptions, benchmarks, and on-chain gas costs.

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The First ZK Exploits Happened, and They Weren't What We Expected

The First ZK Exploits Happened, and They Weren't What We Expected

The first two known exploits against live ZK circuits happened in the past week. Both stem from the same root cause. They were not subtle underconstrained bugs, but rather Groth16 verifiers (generated by snarkjs) with an incorrect setup (just missing the last step). One was exploited by white-hat hackers for ~$1.5M, the other was drained for 5 ETH.

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When LLM Review Cryptography Papers

Google Research used Gemini to find a bug in a cryptography paper on SNARGs from LWE. We summarize how those events unfolded, look at their iterative self-correction prompting strategy and discuss the growing role of LLMs in academic research.

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Zkao: Security That Compounds

Today we're launching zkao, a product by zkSecurity that makes AI security research work the way fuzzing works: not as a one-shot event, but as something you run continuously until coverage compounds.

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