Static Detection of Post-Quantum Cryptographic Algorithms in Stripped Binaries for Digital Forensic Examination and Migration Assurance
Identifying which post-quantum algorithm a compiled binary implements is a core problem in binary analysis, and it becomes acute once the binary has been stripped, statically linked, and optimised, since the symbols, library dependencies, and runtime behaviour that conventional discovery tools rely on are then gone. This paper presents Kestrel, a static analysis method that identifies an algorithm from the number-theoretic transform constant tables its arithmetic depends on, and applies it to the standardised lattice schemes ML-KEM and ML-DSA, for which no prior method could confirm, from a shipped binary alone, that a quantum-vulnerable algorithm had been replaced by its approved successor. The fingerprints Kestrel derives from public scheme parameters are localised by a normalisation-and-multiset-matching procedure; the false-positive probability is established analytically. Across four independent implementation lineages and all build transformations, including compiler-level obfuscation, Kestrel achieved recall of 128 of 128 with zero false positives. Applied to 6,224 binaries on a production Linux system, it disclosed twelve uncatalogued programs containing ML-KEM, among them the OpenSSH key-exchange program and the container-management stack, where post-quantum code had entered production through the language runtime without the awareness of the projects distributing them. Kestrel distinguishes genuine implementations from advertised claims not backed by the underlying code, attributes each detection to its originating codebase, and, in a forensic disk-image trial, recovered a detection from unallocated space after the deleted binary could no longer be reconstructed. It thus provides a practical basis for cryptographic migration assurance, compliance verification, software supply-chain inspection, and post-quantum forensic examination.