diff --git a/chapter_10/public_private/config.ru b/chapter_10/public_private/config.ru
index f9b0fe1..c73deb0 100644
--- a/chapter_10/public_private/config.ru
+++ b/chapter_10/public_private/config.ru
@@ -2,4 +2,4 @@ require 'rsa_sig_validator'
 
 use Rack::RsaSigValidator
 
-run Proc.new { |env| [200, {"Content-Type" => "text/html"}, "Hello World! From Rsa Signature\n"] }
+run Proc.new { |env| [200, {"Content-Type" => "text/html"}, ["Hello World! From Rsa Signature\n"]] }
diff --git a/chapter_10/public_private/rsa_sig_validator.rb b/chapter_10/public_private/rsa_sig_validator.rb
index 63b6c9a..8fd62f4 100644
--- a/chapter_10/public_private/rsa_sig_validator.rb
+++ b/chapter_10/public_private/rsa_sig_validator.rb
@@ -13,7 +13,7 @@ def call(env)
       if signature_is_valid?(env)
         @app.call(env)
       else
-        [401, {"Content-Type" => "text/html"}, "Bad Signature"]
+        [401, {"Content-Type" => "text/html"}, ["Bad Signature"]]
       end
     end