Project Structure

synta-python/              # Python extension crate (cdylib → _synta)
├── Cargo.toml             # Declares crate-type = ["cdylib"]
└── src/
    ├── lib.rs             # #[pymodule] entry point, Encoding enum, pem_to_der/der_to_pem
    ├── types.rs           # ASN.1 primitive type wrappers (Integer, OID, BitString, …)
    ├── decoder.rs         # PyDecoder wrapper
    ├── encoder.rs         # PyEncoder wrapper
    ├── error.rs           # SyntaErr newtype + exception mapping
    ├── certificate/
    │   ├── mod.rs         # re-exports; PKI types live in synta-certificate
    │   ├── cert.rs        # PyCertificate
    │   ├── cert_builder.rs  # CertificateBuilder
    │   ├── csr_builder.rs   # CsrBuilder
    │   ├── name_builder.rs  # NameBuilder
    │   ├── pkix.rs        # CertificateList, OCSPResponse
    │   └── cms/           # synta.cms submodule (RFC 5652 / RFC 9629)
    │       ├── mod.rs     # register_cms_submodule, encode_element_opt helper
    │       ├── container.rs  # ContentInfo, IssuerAndSerialNumber
    │       ├── signed.rs  # SignedData, SignerInfo
    │       ├── enveloped.rs  # EnvelopedData, EncryptedData
    │       ├── digest.rs  # DigestedData, AuthenticatedData
    │       ├── kem.rs     # KEMRecipientInfo, CMSORIforKEMOtherInfo
    │       └── builder.rs # EnvelopedDataBuilder
    ├── ext_builders.rs    # synta.ext submodule: basic_constraints, key_usage, SKI/AKI, SAN/AIA/EKU builders
    ├── crypto.rs          # synta symmetric-crypto primitives (HMAC, PBKDF2, AES, Fernet, OTP)
    ├── crypto_keys.rs     # PublicKey, PrivateKey (RSA, EC, EdDSA)
    └── krb5.rs            # synta.krb5 submodule: Krb5PrincipalName, PKINIT classes

synta-certificate/src/python.rs  # ObjectIdentifier, Certificate, CertificationRequest,
                                 # CertificateList, OCSPResponse, PKCS loaders,
                                 # synta.oids / synta.oids.attr submodules

synta-krb5/src/python.rs         # EncryptionKey, Checksum, KDFAlgorithmId,
                                 # IssuerAndSerialNumber, ExternalPrincipalIdentifier,
                                 # PKAuthenticator, AuthPack, PaPkAsReq,
                                 # DHRepInfo, KDCDHKeyInfo, ReplyKeyPack, PaPkAsRep

python/                    # Python package source (installed by maturin)
├── bench_certificate.py   # Certificate parsing benchmark (synta vs cryptography)
├── bench_x509.py          # Port of cryptography's test_x509.py benchmarks
├── bench_pkcs.py          # PKCS#7 / PKCS#12 extraction benchmark (synta vs cryptography)
├── criterion_compat.py    # Criterion-compatible sampling + JSON output (importable)
└── synta/
    ├── __init__.py        # Package exports (Certificate, PKCS loaders, pem_to_der, …)
    └── py.typed           # PEP 561 marker

pyproject.toml             # Maturin configuration (manifest-path → synta-python)

Key source file roles

All PyO3 bindings live directly in synta-python. The synta-certificate and synta-krb5 library crates have no PyO3 dependency; their types are wrapped in src/certificate.rs and src/pkinit.rs respectively.

See also Cargo Features and Development.