diff --git a/db/migrate/20110826233833_add_algorithm_fields_to_relayable_objects.rb b/db/migrate/20110826233833_add_algorithm_fields_to_relayable_objects.rb
new file mode 100644
index 000000000..ac94e7452
--- /dev/null
+++ b/db/migrate/20110826233833_add_algorithm_fields_to_relayable_objects.rb
@@ -0,0 +1,56 @@
+class AddAlgorithmFieldsToRelayableObjects < ActiveRecord::Migration
+  def self.up
+    add_column :comments, :author_signature_algo, :string
+    add_column :comments, :parent_author_signature_algo, :string
+
+    execute <<SQL
+    UPDATE comments
+      SET comments.author_signature_algo = "SHA"
+    WHERE comments.author_signature IS NOT NULL; 
+SQL
+    execute <<SQL
+    UPDATE comments
+       SET comments.parent_author_signature_algo = "SHA"
+     WHERE comments.author_signature IS NOT NULL
+SQL
+
+    add_column :likes, :author_signature_algo, :string
+    add_column :likes, :parent_author_signature_algo, :string
+
+    execute <<SQL
+    UPDATE likes
+       SET likes.author_signature_algo = "SHA"
+     WHERE likes.author_signature IS NOT NULL
+SQL
+    execute <<SQL
+    UPDATE likes
+       SET likes.parent_author_signature_algo = "SHA"
+     WHERE likes.author_signature IS NOT NULL
+SQL
+
+    add_column :messages, :author_signature_algo, :string
+    add_column :messages, :parent_author_signature_algo, :string
+
+    execute <<SQL
+    UPDATE messages
+       SET messages.author_signature_algo = "SHA"
+     WHERE messages.author_signature IS NOT NULL
+SQL
+    execute <<SQL
+    UPDATE messages
+       SET messages.parent_author_signature_algo = "SHA"
+     WHERE messages.author_signature IS NOT NULL
+SQL
+  end
+
+  def self.down
+    remove_column :messages, :parent_author_signature_algo
+    remove_column :messages, :author_signature_algo
+
+    remove_column :likes, :parent_author_signature_algo
+    remove_column :likes, :author_signature_algo
+
+    remove_column :comments, :parent_author_signature_algo
+    remove_column :comments, :author_signature_algo
+  end
+end