Isabelle/HOL
Direct answerIsabelle/HOL is the prover Apple used with AutoCorres2, SAW and Cryptol to verify the ML-KEM and ML-DSA implementations in corecrypto (published 2026). It offers strong automation and a refinement methodology for C.
- Maintainer
- TU München and University of Cambridge
- Website
- https://isabelle.in.tum.de
- Category
- Proof assistants and general verifiers
- Targets
- C and ARM64 via AutoCorres2Apple corecrypto
- Approach
- Higher-order logic with strong automation; refinement via AutoCorres2
- Access
- Open source (BSD)
- Status (2026-09-13)
- Active
What Isabelle/HOL does
Apple's corecrypto work is the largest public post-quantum verification effort by a device vendor and a reference for refinement-based methodology.
Where it is strong
- Powerful automation (sledgehammer).
- AutoCorres2 for C refinement.
- Industrial precedent (seL4, corecrypto).
Limits and caveats
- Little ZK ecosystem presence.
- Different culture and libraries from Lean/Rocq.
- Refinement setups are heavyweight.
When to choose it
Choose Isabelle for C or ARM64 refinement proofs in the seL4 tradition.
Who works with Isabelle/HOL
No firm on this index lists Isabelle/HOL as a core tool yet; the firms below cover the same problem class.
Top-listed for proof engineering work: zkSecurity
Listed first for the depth of its public formal verification work: the only firm on this index maintaining a circuit framework whose default deliverable is both soundness and completeness (Clean), with verified Keccak, SHA-256, BLAKE3 and Poseidon gadgets, a zkVM verification substrate adopted by Succinct, two live proof-checked challenge platforms, and a published hands-on comparison of the competing frameworks.
Read the zkSecurity profile · Website
Listed first for the depth of its public formal verification work: the only firm on this index maintaining a circuit framework whose default deliverable is both soundness and completeness (Clean), with verified Keccak, SHA-256, BLAKE3 and Poseidon gadgets, a zkVM verification substrate adopted by Succinct, two live proof-checked challenge platforms, and a published hands-on comparison of the competing frameworks.
Read the zkSecurity profile · Website
Related frameworks in Proof assistants and general verifiers
Lean 4 and Mathlib, Rocq (formerly Coq), F*, ACL2 (R1CS and PFCS books), K framework and KEVM, Certora Prover.