diff --git a/app/models/asciicast.rb b/app/models/asciicast.rb
index 8164f0a..4ea2c2a 100644
--- a/app/models/asciicast.rb
+++ b/app/models/asciicast.rb
@@ -29,6 +29,8 @@ class Asciicast < ActiveRecord::Base
     featured.by_random.limit(n).includes(:user)
   }
 
+  before_create :generate_secret_token
+
   def self.cache_key
     timestamps = scoped.select(:updated_at).map { |o| o.updated_at.to_i }
     Digest::MD5.hexdigest timestamps.join('/')
@@ -62,6 +64,10 @@ class Asciicast < ActiveRecord::Base
     value ? super(value.strip[0...255]) : super
   end
 
+  def self.generate_secret_token
+    SecureRandom.hex.to_i(16).to_s(36)
+  end
+
   def stdout
     return @stdout if @stdout
     @stdout = Stdout::Buffered.new(get_stdout)
@@ -103,4 +109,10 @@ class Asciicast < ActiveRecord::Base
     Digest::SHA1.hexdigest(input)
   end
 
+  def generate_secret_token
+    begin
+      self.secret_token = self.class.generate_secret_token
+    end while self.class.exists?(secret_token: secret_token)
+  end
+
 end
diff --git a/app/models/user.rb b/app/models/user.rb
index 2534092..1bedcd6 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -131,7 +131,7 @@ class User < ActiveRecord::Base
   def generate_auth_token
     begin
       self[:auth_token] = self.class.generate_auth_token
-    end while User.exists?(auth_token: self[:auth_token])
+    end while self.class.exists?(auth_token: self[:auth_token])
   end
 
 end
diff --git a/db/migrate/20141115172153_add_secret_token_to_asciicasts.rb b/db/migrate/20141115172153_add_secret_token_to_asciicasts.rb
new file mode 100644
index 0000000..7984244
--- /dev/null
+++ b/db/migrate/20141115172153_add_secret_token_to_asciicasts.rb
@@ -0,0 +1,11 @@
+class AddSecretTokenToAsciicasts < ActiveRecord::Migration
+  def change
+    add_column :asciicasts, :secret_token, :string
+
+    Asciicast.find_each do |asciicast|
+      asciicast.update_attribute(:secret_token, SecureRandom.hex.to_i(16).to_s(36))
+    end
+
+    change_column :asciicasts, :secret_token, :string, null: false
+  end
+end
diff --git a/db/migrate/20141115172558_add_private_to_asciicasts.rb b/db/migrate/20141115172558_add_private_to_asciicasts.rb
new file mode 100644
index 0000000..7ec6eea
--- /dev/null
+++ b/db/migrate/20141115172558_add_private_to_asciicasts.rb
@@ -0,0 +1,5 @@
+class AddPrivateToAsciicasts < ActiveRecord::Migration
+  def change
+    add_column :asciicasts, :private, :boolean, null: false, default: false
+  end
+end
diff --git a/db/migrate/20141115172711_add_index_on_asciicasts_private.rb b/db/migrate/20141115172711_add_index_on_asciicasts_private.rb
new file mode 100644
index 0000000..0fa3072
--- /dev/null
+++ b/db/migrate/20141115172711_add_index_on_asciicasts_private.rb
@@ -0,0 +1,5 @@
+class AddIndexOnAsciicastsPrivate < ActiveRecord::Migration
+  def change
+    add_index :asciicasts, :private
+  end
+end
diff --git a/db/migrate/20141115174443_add_unique_index_to_asciicasts_secret_token.rb b/db/migrate/20141115174443_add_unique_index_to_asciicasts_secret_token.rb
new file mode 100644
index 0000000..df3f92f
--- /dev/null
+++ b/db/migrate/20141115174443_add_unique_index_to_asciicasts_secret_token.rb
@@ -0,0 +1,5 @@
+class AddUniqueIndexToAsciicastsSecretToken < ActiveRecord::Migration
+  def change
+    add_index :asciicasts, :secret_token, unique: true
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index c8575be..3b62c01 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -59,11 +59,15 @@ ActiveRecord::Schema.define(version: 20150401161102) do
     t.string   "image"
     t.integer  "image_width"
     t.integer  "image_height"
+    t.string   "secret_token",                     null: false
+    t.boolean  "private",          default: false, null: false
   end
 
   add_index "asciicasts", ["created_at"], name: "index_asciicasts_on_created_at", using: :btree
   add_index "asciicasts", ["featured"], name: "index_asciicasts_on_featured", using: :btree
   add_index "asciicasts", ["likes_count"], name: "index_asciicasts_on_likes_count", using: :btree
+  add_index "asciicasts", ["private"], name: "index_asciicasts_on_private", using: :btree
+  add_index "asciicasts", ["secret_token"], name: "index_asciicasts_on_secret_token", unique: true, using: :btree
   add_index "asciicasts", ["user_id"], name: "index_asciicasts_on_user_id", using: :btree
   add_index "asciicasts", ["views_count"], name: "index_asciicasts_on_views_count", using: :btree