Files
Borealis-Github-Replica/Data/Engine/security/signing.py

91 lines
2.8 KiB
Python

# ======================================================
# Data\Engine\security\signing.py
# Description: Manages Engine code-signing keys under Engine/Certificates/Code-Signing without legacy fallbacks.
#
# API Endpoints (if applicable): None
# ======================================================
"""Engine code-signing helper utilities."""
from __future__ import annotations
import base64
import os
from pathlib import Path
from cryptography.hazmat.primitives import serialization
from cryptography.hazmat.primitives.asymmetric import ed25519
from .certificates import engine_code_signing_root
__all__ = ["ScriptSigner", "load_signer", "base64_from_spki_der"]
_KEY_DIR = engine_code_signing_root()
_SIGNING_KEY_FILE = _KEY_DIR / "borealis-script-ed25519.key"
_SIGNING_PUB_FILE = _KEY_DIR / "borealis-script-ed25519.pub"
def base64_from_spki_der(spki_der: bytes) -> str:
"""Return Base64 representation for SubjectPublicKeyInfo DER bytes."""
return base64.b64encode(spki_der).decode("ascii")
def _tighten_permissions(path: Path) -> None:
try:
if os.name != "nt":
path.chmod(0o600)
except Exception:
pass
class ScriptSigner:
"""Wrap an Ed25519 private key with convenience helpers."""
def __init__(self, private_key: ed25519.Ed25519PrivateKey):
self._private = private_key
self._public = private_key.public_key()
def sign(self, payload: bytes) -> bytes:
return self._private.sign(payload)
def public_spki_der(self) -> bytes:
return self._public.public_bytes(
encoding=serialization.Encoding.DER,
format=serialization.PublicFormat.SubjectPublicKeyInfo,
)
def public_base64_spki(self) -> str:
return base64_from_spki_der(self.public_spki_der())
def load_signer() -> ScriptSigner:
"""Load (or create) the Engine script-signing key pair."""
private_key = _load_or_create()
return ScriptSigner(private_key)
def _load_or_create() -> ed25519.Ed25519PrivateKey:
_KEY_DIR.mkdir(parents=True, exist_ok=True)
if _SIGNING_KEY_FILE.exists():
with _SIGNING_KEY_FILE.open("rb") as handle:
return serialization.load_pem_private_key(handle.read(), password=None)
private_key = ed25519.Ed25519PrivateKey.generate()
pem = private_key.private_bytes(
encoding=serialization.Encoding.PEM,
format=serialization.PrivateFormat.PKCS8,
encryption_algorithm=serialization.NoEncryption(),
)
_SIGNING_KEY_FILE.write_bytes(pem)
_tighten_permissions(_SIGNING_KEY_FILE)
pub_der = private_key.public_key().public_bytes(
encoding=serialization.Encoding.DER,
format=serialization.PublicFormat.SubjectPublicKeyInfo,
)
_SIGNING_PUB_FILE.write_bytes(pub_der)
return private_key