diff --git a/app/channels/api_channel.rb b/app/channels/api_channel.rb
index 2e3746e9..697eb78c 100644
--- a/app/channels/api_channel.rb
+++ b/app/channels/api_channel.rb
@@ -153,6 +153,8 @@ def finish data
     dispatch_all 'comments/load', Comment.includes(:user).where(task_id:)
     dispatch_all 'app/finish'
 
+    dispatch_self 'notifications/push', kind: 'info', message: 'Calculating results …'
+
     users_without_result = []
     begin
       result_multiplier = Rational task.result_multiplier
@@ -171,6 +173,8 @@ def finish data
       task.update_column :scoring_open, true
       dispatch_self 'app/ready', ready_info
       raise e
+    else
+      dispatch_self 'notifications/push', kind: 'success', message: 'Results calculated'
     end
   end
 
diff --git a/app/controllers/users_controller.rb b/app/controllers/users_controller.rb
index ea92b862..65bf441e 100644
--- a/app/controllers/users_controller.rb
+++ b/app/controllers/users_controller.rb
@@ -22,7 +22,8 @@ def collection
   end
 
   def resource_params
-    params.require(:user).permit(PERMITTED_PARAMS).merge(registration_ips: ip_addresses, device_id: @device_id)
+    params.require(:user).permit(PERMITTED_PARAMS)
+      .merge(registration_ips: ip_addresses, device_id: @device_id, registration_secret_required: true)
   end
 
   def initialize_resource
diff --git a/app/models/user.rb b/app/models/user.rb
index ad705182..a83e4e1c 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -1,10 +1,13 @@
 class User < ApplicationRecord
-  attr_accessor :registration_secret
+  attr_accessor :registration_secret, :registration_secret_required
 
   validates :name, :email, :city, :institution, :contest_site, :grade, presence: true
   validates :name, :secret, :judge_secret, uniqueness: { scope: :contest }
-  validates :registration_secret, presence: true, on: :create
-  validate :registration_secret_must_be_valid, on: :create
+
+  with_options if: :registration_secret_required, on: :create do
+    validates :registration_secret, presence: true
+    validate :registration_secret_must_be_valid
+  end
 
   belongs_to :contest, inverse_of: :users
   has_many :solutions, inverse_of: :user, dependent: :destroy
diff --git a/config/initializers/rails_admin.rb b/config/initializers/rails_admin.rb
index 8864509f..93efc583 100644
--- a/config/initializers/rails_admin.rb
+++ b/config/initializers/rails_admin.rb
@@ -78,10 +78,18 @@
   config.model 'Task' do |_config|
     configure :file_names, :pg_string_array
     configure :judges, :pg_string_array
+    configure(:solutions) { hide }
+    configure(:results) { hide }
+    configure(:criterions) { hide }
+    configure(:comments) { hide }
   end
 
   config.model 'User' do |_config|
     configure :registration_ips, :pg_inet_array
+    configure(:solutions) { hide }
+    configure(:results) { hide }
+    configure(:comments) { hide }
+    configure(:criterion_user_results) { hide }
   end
 
   config.model 'Solution' do |_config|
@@ -92,5 +100,12 @@
     configure :cities, :pg_string_array
     configure :institutions, :pg_string_array
     configure :contest_sites, :pg_string_array
+    configure(:tasks) { hide }
+    configure(:users) { hide }
+    configure(:solutions) { hide }
+  end
+
+  config.model 'Criterion' do |_config|
+    configure(:criterion_user_results) { hide }
   end
 end