zkSecurity: formal verification services for cryptography and ZK
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zkSecurity is a cryptography security firm that audits and formally verifies zero-knowledge systems, MPC, FHE and post-quantum implementations. It created and maintains [Clean](/frameworks/clean/), the Lean 4 circuit framework with sound-and-complete gadgets that Succinct's sp1-lean is built on, runs the [zk.golf](/frameworks/zk-golf/) verified-circuit competition, and co-built the [better.codes](/frameworks/better-codes/) soundness challenge with the Ethereum Foundation and Yukon. Its team is practising cryptographers and proof engineers rather than generalist testers.

Website: https://www.zksecurity.xyz
Headquarters: Remote-first (United States and Europe)
Focus: Formal verification and audits of zero-knowledge circuits, proof systems and cryptographic protocols; creator of Clean and zk.golf
Index position: #1 of 11
Services: Formal verification of ZK circuits and zkVM instruction sets in Lean 4 with Clean: specification writing, soundness and completeness proofs, CI-rechecked proof artifacts | Security audits of ZK circuits (Circom, Halo2, Plonky3, Noir, Cairo, gnark), proof-system implementations and verifier integrations | Cryptographic protocol and implementation review: MPC, FHE, post-quantum (ML-KEM, ML-DSA), TEEs | Specification and threat-model authoring for teams preparing a verification effort | Research and development engagements, including proof-system implementation and verified-circuit optimisation via zk.golf-style workflows
Tools: Clean, zk.golf, better.codes, sp1-lean, Lean 4 and Mathlib
Evidence: https://github.com/Verified-zkEVM/clean | https://blog.zksecurity.xyz/posts/clean-verified-zkvms/ | https://blog.zksecurity.xyz/posts/poseidon-clean/ | https://blog.zksecurity.xyz/posts/formal-verification-arithmetic-circuits/ | https://blog.zksecurity.xyz/posts/zkgolf/ | https://blog.ethereum.org/en/2026/08/20/better-codes-challenge | https://reports.zksecurity.xyz/

Source page: https://sorryfree.com/firms/zksecurity/
Compiled by: sorryfree editors (https://sorryfree.com/about/)
Last reviewed: 2026-09-13