补齐模型管理与基础生成预览链路

backend/services/security.py

@@ -0,0 +1,35 @@
+import base64
+import hashlib
+
+from cryptography.fernet import Fernet, InvalidToken
+
+from config import settings
+
+
+def _build_fernet() -> Fernet:
+    raw_key = settings.ENCRYPTION_KEY.encode("utf-8")
+    digest = hashlib.sha256(raw_key).digest()
+    return Fernet(base64.urlsafe_b64encode(digest))
+
+
+def encrypt_text(value: str) -> str:
+    if not value:
+        return ""
+    return _build_fernet().encrypt(value.encode("utf-8")).decode("utf-8")
+
+
+def decrypt_text(value: str) -> str:
+    if not value:
+        return ""
+    try:
+        return _build_fernet().decrypt(value.encode("utf-8")).decode("utf-8")
+    except InvalidToken:
+        return ""
+
+
+def mask_secret(value: str) -> str:
+    if not value:
+        return ""
+    if len(value) <= 7:
+        return "*" * len(value)
+    return f"{value[:3]}****{value[-4:]}"