ishenwei
9a7d06b34e
Phase 1 scaffolding: config/, core/, base models, AES-256-GCM phone encryption, enums mirror apps.tenant: Tenant + Domain (django-tenants) apps.org: 11 models (OrgUnit hierarchy, Staff, audit logs) apps.account: 4 models (UserAccount as AUTH_USER_MODEL, login/password tracking) apps.permission: 7 models (RBAC + overrides + datascope + append-only changelog) apps.region: 5 models (District, BusinessArea, MetroLine, MetroStation, School) All migrations generated, manage.py check passes
58 lines
1.9 KiB
Python
58 lines
1.9 KiB
Python
"""PII encryption per AGENTS.md §4.4: AES-256-GCM (NOT Fernet)."""
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import base64
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import hashlib
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import os
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from django.conf import settings
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from cryptography.hazmat.primitives.ciphers.aead import AESGCM
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class PhoneEncryption:
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"""Encrypt phone numbers with AES-256-GCM, index via SHA-256 hash, display masked.
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Storage: phone_encrypted = base64(nonce || ciphertext || tag)
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Index: phone_hash = sha256(plaintext) — used for equality lookups
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Display: 138****1234
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"""
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NONCE_LEN = 12
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@staticmethod
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def _key() -> bytes:
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key_b64 = settings.PHONE_ENCRYPTION_KEY
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if not key_b64:
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raise RuntimeError(
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"PHONE_ENCRYPTION_KEY is not configured. "
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"Generate with: python -c 'import secrets,base64; print(base64.b64encode(secrets.token_bytes(32)).decode())'"
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)
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key = base64.b64decode(key_b64)
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if len(key) != 32:
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raise RuntimeError("PHONE_ENCRYPTION_KEY must decode to exactly 32 bytes (AES-256).")
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return key
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@classmethod
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def encrypt(cls, phone: str) -> str:
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if phone is None:
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raise ValueError("phone cannot be None")
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aesgcm = AESGCM(cls._key())
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nonce = os.urandom(cls.NONCE_LEN)
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ct = aesgcm.encrypt(nonce, phone.encode("utf-8"), None)
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return base64.b64encode(nonce + ct).decode("ascii")
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@classmethod
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def decrypt(cls, ciphertext_b64: str) -> str:
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raw = base64.b64decode(ciphertext_b64)
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nonce, ct = raw[: cls.NONCE_LEN], raw[cls.NONCE_LEN :]
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aesgcm = AESGCM(cls._key())
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return aesgcm.decrypt(nonce, ct, None).decode("utf-8")
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@staticmethod
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def hash(phone: str) -> str:
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return hashlib.sha256(phone.encode("utf-8")).hexdigest()
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@staticmethod
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def mask(phone: str) -> str:
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if not phone or len(phone) < 7:
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return "***"
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return phone[:3] + "****" + phone[-4:]
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