Initial

backend/app/utils.py

@@ -0,0 +1,28 @@
+from django.utils.crypto import get_random_string
+from cryptography.hazmat.primitives.ciphers.aead import AESGCM
+from cryptography.hazmat.primitives.hashes import Hash, SHA256
+
+import os
+import typing
+
+if typing.TYPE_CHECKING:
+    from app.models.member import Member
+
+
+def random_secret():
+    return get_random_string(16)
+
+
+def overwrite_upload(instance: 'Member', filename: str):
+    if os.path.isfile(instance.image_os_path):
+        os.remove(instance.image_os_path)
+    return instance.image_save_url
+
+
+def encrypt(plaintext: str, key: str):
+    digest = Hash(SHA256())
+    digest.update(key.encode('utf8'))
+    aesgcm = AESGCM(digest.finalize())
+    iv = os.urandom(12)
+    ct = aesgcm.encrypt(iv, plaintext.encode('utf8'), iv)
+    return iv + ct