feat: govern legacy archive encryption

src/govoplan_campaign/backend/campaign/models.py

@@ -76,6 +76,14 @@ class ZipPasswordScope(StrEnum):
     GLOBAL = "global"
 
 
+class ZipPasswordDeliveryChannel(StrEnum):
+    SEPARATE_MAIL = "separate_mail"
+    SMS = "sms"
+    LETTER = "letter"
+    PHONE = "phone"
+    IN_PERSON = "in_person"
+
+
 class ZipPasswordMode(StrEnum):
     NONE = "none"
     DIRECT = "direct"
@@ -349,6 +357,13 @@ class ZipArchiveConfig(StrictModel):
     password_field: str | None = None
     password_scope: ZipPasswordScope = ZipPasswordScope.LOCAL
     method: ZipMethod = ZipMethod.AES
+    password_delivery_channel: ZipPasswordDeliveryChannel = (
+        ZipPasswordDeliveryChannel.SEPARATE_MAIL
+    )
+    legacy_zipcrypto_acknowledged: bool = False
+    legacy_zipcrypto_reason: str | None = Field(default=None, max_length=1000)
+    legacy_zipcrypto_acknowledged_by: str | None = Field(default=None, max_length=255)
+    legacy_zipcrypto_acknowledged_at: str | None = Field(default=None, max_length=80)
 
     # Compatibility fields for campaigns created by the first single-archive
     # implementation. New WebUI campaigns use password_enabled/field/scope.
@@ -376,6 +391,20 @@ class ZipArchiveConfig(StrictModel):
             normalized["password_scope"] = ZipPasswordScope.LOCAL.value
         return normalized
 
+    @model_validator(mode="after")
+    def validate_legacy_zipcrypto_acknowledgement(self) -> "ZipArchiveConfig":
+        if self.method != ZipMethod.ZIP_STANDARD:
+            return self
+        if not self.legacy_zipcrypto_acknowledged:
+            raise ValueError(
+                "Legacy ZipCrypto requires explicit acknowledgement of its weak encryption"
+            )
+        if len((self.legacy_zipcrypto_reason or "").strip()) < 10:
+            raise ValueError(
+                "Legacy ZipCrypto requires an acknowledgement reason of at least 10 characters"
+            )
+        return self
+
 
 class ZipCollectionConfig(StrictModel):
     enabled: bool = False