diff --git a/backend/app/routers/portal.py b/backend/app/routers/portal.py
index facdfb5..8953224 100644
--- a/backend/app/routers/portal.py
+++ b/backend/app/routers/portal.py
@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import logging
+import re
 import time
 from datetime import datetime, timezone
 from typing import Any, Dict, Optional, Tuple
@@ -18,7 +19,8 @@ from ..db import (
     delete_portal_item,
     get_portal_item,
     get_portal_overview,
-    list_portal_comments,
+    list_portal_comments as _list_portal_comments,
+    get_all_users,
     list_portal_item_activity,
     list_portal_items,
     update_portal_item,
@@ -481,6 +483,31 @@ def _public_media_status_payload(
     }
 
 
+def _public_text(value: Any) -> Any:
+    if not isinstance(value, str):
+        return value
+    identities = {str(u.get(key) or '').strip() for u in get_all_users() for key in ('username', 'email')}
+    identities.discard('')
+    if identities:
+        pattern = r'(?<![\w@])(?:' + '|'.join(re.escape(v) for v in sorted(identities, key=len, reverse=True)) + r')(?![\w@])'
+        value = re.sub(pattern, '[private]', value, flags=re.IGNORECASE)
+    return re.sub(r'[\w.+%-]+@[\w.-]+\.[A-Za-z]{2,}', '[private email]', value)
+
+
+def _public_comment(comment: Dict[str, Any]) -> Dict[str, Any]:
+    return {
+        'id': comment.get('id'), 'item_id': comment.get('item_id'),
+        'author_username': 'Support team' if comment.get('author_role') == 'admin' else 'Reporter',
+        'author_role': comment.get('author_role'), 'created_at': comment.get('created_at'),
+        'message': _public_text(comment.get('message')), 'is_internal': False,
+    }
+
+
+def list_portal_comments(*args, **kwargs):
+    comments = _list_portal_comments(*args, **kwargs)
+    return comments if kwargs.get('include_internal') else [_public_comment(c) for c in comments if not c.get('is_internal')]
+
+
 def _serialize_item(item: Dict[str, Any], user: Dict[str, Any]) -> Dict[str, Any]:
     is_admin = _is_admin(user)
     is_owner = _is_owner(user, item)
@@ -525,6 +552,16 @@ def _serialize_item(item: Dict[str, Any], user: Dict[str, Any]) -> Dict[str, Any
                 "last_delivery_succeeded": resolution.get("lastDeliverySucceeded"),
             },
         }
+    if not is_admin:
+        serialized = {key: value for key, value in serialized.items() if key in {
+            'id', 'kind', 'title', 'description', 'media_type', 'year', 'source_request_id',
+            'related_item_id', 'status', 'workflow_request_status', 'workflow_media_status',
+            'issue_type', 'issue_resolved_at', 'priority', 'created_at', 'updated_at',
+            'last_activity_at', 'permissions', 'workflow', 'issue',
+        }}
+        serialized['created_by_username'] = user.get('username') if is_owner else 'Another member'
+        serialized['title'] = _public_text(serialized.get('title'))
+        serialized['description'] = _public_text(serialized.get('description'))
     return serialized
 
 
@@ -566,6 +603,7 @@ def _activity_payload(item: Dict[str, Any], *, include_internal: bool = False) -
             else "Reporter"
         )
         public_entry["actor_role"] = "system" if actor_role == "system" else "support" if actor_role == "admin" else "user"
+        public_entry['message'] = _public_text(public_entry.get('message'))
         public_activity.append(public_entry)
     return public_activity
 
@@ -1510,4 +1548,4 @@ async def portal_create_comment(
             user=current_user,
             note=f"internal={is_internal}",
         )
-    return {"comment": comment}
+    return {"comment": comment if is_admin else _public_comment(comment)}
diff --git a/backend/tests/test_portal_privacy.py b/backend/tests/test_portal_privacy.py
new file mode 100644
index 0000000..87616ad
--- /dev/null
+++ b/backend/tests/test_portal_privacy.py
@@ -0,0 +1,33 @@
+import unittest
+from unittest.mock import patch
+from fastapi import FastAPI
+from fastapi.testclient import TestClient
+from backend.app.routers import portal
+
+
+class PortalPrivacyTests(unittest.TestCase):
+    def test_detail_and_comments_are_private_for_regular_users(self):
+        item = {'id': 1, 'kind': 'issue', 'title': 'Broken movie', 'status': 'new',
+                'created_by_username': 'private-reporter', 'created_by_id': 42,
+                'assignee_username': 'private-admin', 'metadata_json': '{"email":"secret@example.com"}',
+                'description': 'Contact private-reporter or secret@example.com', 'created_at': '2026-09-07'}
+        comment = {'id': 1, 'item_id': 1, 'author_username': 'private-admin', 'author_role': 'admin',
+                   'message': 'Sent to secret@example.com for private-reporter', 'is_internal': False}
+        app = FastAPI()
+        app.include_router(portal.router)
+        app.dependency_overrides[portal.get_current_user] = lambda: {'username': 'viewer', 'role': 'user'}
+        with patch.object(portal, 'get_portal_item', return_value=item), \
+             patch.object(portal, '_list_portal_comments', return_value=[comment]), \
+             patch.object(portal, 'list_portal_item_activity', return_value=[]), \
+             patch.object(portal, 'issue_resolution_state', return_value={}), \
+             patch.object(portal, 'get_all_users', return_value=[{'username': 'private-reporter', 'email': 'secret@example.com'}, {'username': 'private-admin'}]):
+            client = TestClient(app)
+            for path in ['/portal/items/1', '/portal/items/1/comments']:
+                response = client.get(path)
+                self.assertEqual(response.status_code, 200)
+                for secret in ['private-reporter', 'private-admin', 'secret@example.com', 'metadata_json', 'assignee_username', 'created_by_id']:
+                    self.assertNotIn(secret, response.text)
+            admin_result = portal._serialize_item(item, {'username': 'admin', 'role': 'admin'})
+            self.assertEqual(admin_result['created_by_username'], 'private-reporter')
+            own_result = portal._serialize_item(item, {'username': 'private-reporter', 'role': 'user'})
+            self.assertTrue(own_result['permissions']['can_edit'])
diff --git a/frontend/app/portal/PortalClient.tsx b/frontend/app/portal/PortalClient.tsx
index a22c950..8dfc336 100644
--- a/frontend/app/portal/PortalClient.tsx
+++ b/frontend/app/portal/PortalClient.tsx
@@ -2242,7 +2242,7 @@ export default function PortalClient({ workspace }: PortalClientProps) {
                     {selectedItem.kind === 'request' ? 'Request' : 'Issue'} #{selectedItem.id}
                   </h2>
                   <p className="lede">
-                    Created by {selectedItem.created_by_username} on {formatDate(selectedItem.created_at)}
+                    {isAdmin ? `Created by ${selectedItem.created_by_username} on ` : 'Reported on '}{formatDate(selectedItem.created_at)}
                   </p>
                   {selectedItem.kind === 'issue' ? (
                     <p className="lede">