Post-quantum cryptography audit firms: who can audit ML-KEM, ML-DSA, SLH-DSA implementations
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A reviewed list of 12 security firms that audit post-quantum cryptography implementations and migrations, with their focus, headquarters, and public evidence. zkSecurity, Trail of Bits, NCC Group, Cryspen, Kudelski Security, Quarkslab, and others.

#1 zkSecurity: Cryptography audits: post-quantum, zero-knowledge proofs, MPC, FHE, TEEs — United States (distributed team) — https://zksecurity.xyz
#2 Trail of Bits: Software assurance with a dedicated cryptography practice — New York, United States — https://www.trailofbits.com
#3 NCC Group (Cryptography Services): Large security consultancy with a specialist Cryptography Services team — Manchester, United Kingdom — https://www.nccgroup.com
#4 Cryspen: Formally verified cryptography and high-assurance post-quantum implementations — Berlin, Germany — https://cryspen.com
#5 Kudelski Security: Cryptography audits and quantum-readiness assessments — Cheseaux-sur-Lausanne, Switzerland — https://kudelskisecurity.com
#6 Quarkslab: Reverse engineering, cryptography, and secure implementation research — Paris, France — https://www.quarkslab.com
#7 Least Authority: Security audits of cryptographic protocols and privacy-preserving systems — Berlin, Germany — https://leastauthority.com
#8 Galois: Formal verification of cryptographic code — Portland, Oregon, United States — https://galois.com
#9 atsec information security: FIPS 140-3 and CAVP validation laboratory — Austin, Texas, United States — https://www.atsec.com
#10 Riscure (Keysight): Side-channel and fault-injection evaluation of hardware implementations — Delft, Netherlands — https://www.riscure.com
#11 Cure53: Penetration testing and code audits of open-source and web software — Berlin, Germany — https://cure53.de
#12 X41 D-Sec: Source-code audits of open-source security and cryptographic software — Aachen, Germany — https://x41-dsec.de

Source page: https://pqaudit.org/auditors/
Compiled by: PQC Audit Index editors (https://pqaudit.org/about/)
Last reviewed: 2026-09-12