Pure PKI domain logic for KCA. It knows how to generate and parse keys, build distinguished names, encode X.509 extensions, issue certificates, create CSRs and CRLs, apply templates, and convert every supported import and export format. It has no kaya or database dependencies and is unit-tested in isolation. Native operations use cryptography; an in-memory CFFI/OpenSSL 3 backend supports XCA's legacy named curves and signature hashes without private-key temporary files or command-line tools.