diff --git a/app/controllers/calendars_controller.rb b/app/controllers/calendars_controller.rb
index e97ba0ad2..ad1801c78 100644
--- a/app/controllers/calendars_controller.rb
+++ b/app/controllers/calendars_controller.rb
@@ -32,7 +32,7 @@ def show
   end
 
   def create_calendar
-    @member = Member.find(params[:hash])
+    @member = Member.find_by(calendar_id: params[:calendar_id])
     events = @member.activities.map { |a| IcalendarHelper.activityToEvent(a) }
     IcalendarHelper.createCalendar(events).to_ical
   end
diff --git a/config/routes.rb b/config/routes.rb
index b70013a07..84f88c6c6 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -1,5 +1,5 @@
 Rails.application.routes.draw do
-  get 'calendar/:hash', to: 'calendars#show', defaults: { format: 'ics' }
+  get 'calendar/:calendar_id', to: 'calendars#show', defaults: { format: 'ics' }
 
   use_doorkeeper_openid_connect
 
diff --git a/db/migrate/20240521180025_add_calendar_id_to_member.rb b/db/migrate/20240521180025_add_calendar_id_to_member.rb
new file mode 100644
index 000000000..da7f4da90
--- /dev/null
+++ b/db/migrate/20240521180025_add_calendar_id_to_member.rb
@@ -0,0 +1,5 @@
+class AddCalendarIdToMember < ActiveRecord::Migration[6.1]
+  def change
+    add_column :members, :calendar_id, :uuid
+  end
+end
diff --git a/db/seeds/members.rb b/db/seeds/members.rb
index 8b5e3ee0d..9b51941fc 100644
--- a/db/seeds/members.rb
+++ b/db/seeds/members.rb
@@ -18,7 +18,8 @@
     student_id:   "F#{ Faker::Number.number(digits: 6) }",
     birth_date:   Faker::Date.between(from: 28.years.ago, to: 16.years.ago),
     join_date:    Faker::Date.between(from: 6.years.ago, to: Date.today),
-    comments:     (Faker::Boolean.boolean(true_ratio: 0.3) ? Faker::Hacker.say_something_smart : nil)
+    comments:     (Faker::Boolean.boolean(true_ratio: 0.3) ? Faker::Hacker.say_something_smart : nil),
+    calendar_id:  Faker::Boolean.boolean(true_ratio: 0.4) ? SecureRandom.uuid : nil
   )
 
   puts("   -> #{ member.name } (#{ member.student_id })")
diff --git a/db/structure.sql b/db/structure.sql
index 075e5bfba..1ab61df75 100644
--- a/db/structure.sql
+++ b/db/structure.sql
@@ -550,7 +550,8 @@ CREATE TABLE public.members (
     consent integer DEFAULT 0,
     consent_at date,
     created_at timestamp without time zone,
-    updated_at timestamp without time zone
+    updated_at timestamp without time zone,
+    calendar_id uuid
 );
 
 
@@ -1736,6 +1737,7 @@ INSERT INTO "schema_migrations" (version) VALUES
 ('20220221195220'),
 ('20220406092056'),
 ('20220524203723'),
-('20240125003700');
+('20240125003700'),
+('20240521180025');
 
 
diff --git a/lib/icalendar_helper.rb b/lib/icalendar_helper.rb
index 1f06e63cf..bc8e152e7 100644
--- a/lib/icalendar_helper.rb
+++ b/lib/icalendar_helper.rb
@@ -9,7 +9,7 @@ def IcalendarHelper.activityToEvent(activity)
     event.dtstart = activity.start_date
     event.dtend = activity.end_date
     event.summary = activity.name
-    event.description = activity.description_nl
+    event.description = activity.description_nl # TODO localise
     event.location = activity.location
     return event
   end