synta 0.2.6

ASN.1 parser, decoder, and encoder library with DER/BER support and C FFI
Documentation 
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#!/usr/bin/env python3
"""
Example 10: Format-agnostic PKI reader.

Demonstrates: read_pki_blocks — accepts PEM, DER, PKCS#7, and PKCS#12 bytes and
returns a list of (label, der_bytes) tuples.

Labels returned:
  "CERTIFICATE"  — X.509 certificate (from any format)
  "PRIVATE KEY"  — PKCS#8 OneAsymmetricKey (from PKCS#12 keyBag /
                   pkcs8ShroudedKeyBag, or PEM PRIVATE KEY blocks)
"""

import pathlib
import synta

VECTORS = pathlib.Path(__file__).parent.parent / "tests" / "vectors"
CRYPTO_PKCS12 = (
    VECTORS
    / "cryptography"
    / "vectors"
    / "cryptography_vectors"
    / "pkcs12"
)


def section(title):
    print(f"\n{'─' * 60}\n{title}\n{'─' * 60}")


def demo_pem_input():
    section("read_pki_blocks — PEM certificate input")
    path = VECTORS / "test_certificate.pem"
    if not path.exists():
        print(f"  Skipped: {path} not found")
        return
    pem_data = path.read_bytes()
    blocks = synta.read_pki_blocks(pem_data)
    print(f"  Found {len(blocks)} block(s)")
    for label, der in blocks:
        print(f"  label={label!r}  der_len={len(der)}")
        cert = synta.Certificate.from_der(der)
        print(f"    subject={cert.subject}")


def demo_der_input():
    section("read_pki_blocks — DER certificate input")
    path = VECTORS / "test_certificate.der"
    if not path.exists():
        print(f"  Skipped: {path} not found")
        return
    der_data = path.read_bytes()
    blocks = synta.read_pki_blocks(der_data)
    print(f"  Found {len(blocks)} block(s)")
    for label, der in blocks:
        print(f"  label={label!r}  der_len={len(der)}")


def demo_pkcs7_input():
    section("read_pki_blocks — PKCS#7 bundle input")
    path = VECTORS / "test_bundle_2certs.p7b"
    if not path.exists():
        print(f"  Skipped: {path} not found")
        return
    p7b_data = path.read_bytes()
    blocks = synta.read_pki_blocks(p7b_data)
    print(f"  Found {len(blocks)} block(s)")
    for i, (label, der) in enumerate(blocks):
        cert = synta.Certificate.from_der(der)
        print(f"  [{i}] label={label!r}  subject={cert.subject}")


def demo_pkcs12_no_password():
    section("read_pki_blocks — PKCS#12 (no password, certs only)")
    path = VECTORS / "test_bundle_nopass.p12"
    if not path.exists():
        print(f"  Skipped: {path} not found")
        return
    p12_data = path.read_bytes()
    blocks = synta.read_pki_blocks(p12_data)
    print(f"  Found {len(blocks)} block(s)")
    for i, (label, der) in enumerate(blocks):
        cert = synta.Certificate.from_der(der)
        print(f"  [{i}] label={label!r}  subject={cert.subject}")


def demo_pkcs12_with_key():
    section("read_pki_blocks — PKCS#12 with cert + unencrypted key")
    path = CRYPTO_PKCS12 / "cert-none-key-none.p12"
    if not path.exists():
        print(f"  Skipped: {path} not found")
        return
    p12_data = path.read_bytes()
    blocks = synta.read_pki_blocks(p12_data)
    print(f"  Found {len(blocks)} block(s)")
    for i, (label, der) in enumerate(blocks):
        if label == "CERTIFICATE":
            cert = synta.Certificate.from_der(der)
            print(f"  [{i}] label={label!r}  subject={cert.subject}")
        else:
            # "PRIVATE KEY" — raw PKCS#8 DER, tag 0x30
            print(f"  [{i}] label={label!r}  der_len={len(der)} bytes  tag=0x{der[0]:02x}")


def demo_pkcs12_with_password():
    section("read_pki_blocks — PKCS#12 with password")
    path = VECTORS / "test_bundle_pass.p12"
    if not path.exists():
        print(f"  Skipped: {path} not found")
        return
    p12_data = path.read_bytes()
    try:
        blocks = synta.read_pki_blocks(p12_data, b"synta")
        print(f"  Found {len(blocks)} block(s) with correct password")
        for i, (label, der) in enumerate(blocks):
            if label == "CERTIFICATE":
                cert = synta.Certificate.from_der(der)
                print(f"  [{i}] label={label!r}  subject={cert.subject}")
            else:
                print(f"  [{i}] label={label!r}  der_len={len(der)} bytes")
    except ValueError as e:
        print(f"  ValueError: {e}")
        print("  (Encrypted PKCS#12 requires the 'openssl' feature)")


def demo_multi_block_pem():
    section("read_pki_blocks — multi-block PEM chain")
    pem1 = (VECTORS / "test_certificate.pem").read_bytes()
    pem2 = (VECTORS / "test_certificate2.pem").read_bytes()
    if not (VECTORS / "test_certificate.pem").exists():
        print("  Skipped: test vectors not found")
        return
    blocks = synta.read_pki_blocks(pem1 + pem2)
    print(f"  Found {len(blocks)} block(s) in two-cert PEM chain")
    for label, der in blocks:
        print(f"  label={label!r}  der_len={len(der)}")


def main():
    print("=" * 60)
    print("Example 10: Format-agnostic PKI reader (read_pki_blocks)")
    print("=" * 60)
    demo_pem_input()
    demo_der_input()
    demo_pkcs7_input()
    demo_pkcs12_no_password()
    demo_pkcs12_with_key()
    demo_pkcs12_with_password()
    demo_multi_block_pem()
    print("\nAll read_pki_blocks examples completed.")


if __name__ == "__main__":
    main()