Adding otp methods.

lib/two_factor_authentication/hooks/two_factor_authenticatable.rb

@@ -1,9 +1,7 @@
 Warden::Manager.after_authentication do |user, auth, options|
   if user.respond_to?(:need_two_factor_authentication?)
     if auth.session(options[:scope])[:need_two_factor_authentication] = user.need_two_factor_authentication?(auth.request)
-      code = user.generate_two_factor_code
-      user.second_factor_pass_code = Digest::MD5.hexdigest(code)
-      user.save
+      code = user.otp_code
       user.send_two_factor_authentication_code(code)
     end
   end

lib/two_factor_authentication/models/two_factor_authenticatable.rb

@@ -5,15 +5,55 @@ module Devise
       extend ActiveSupport::Concern
 
       module ClassMethods
+        def has_one_time_password(options = {})
+
+          cattr_accessor :otp_column_name
+          self.otp_column_name = (options[:column_name] || "otp_secret_key").to_s
+
+          include InstanceMethodsOnActivation
+
+          before_create { self.otp_column = ROTP::Base32.random_base32 }
+
+          if respond_to?(:attributes_protected_by_default)
+            def self.attributes_protected_by_default #:nodoc:
+              super + [self.otp_column_name]
+            end
+          end
+        end
         ::Devise::Models.config(self, :login_code_random_pattern, :max_login_attempts)
       end
 
-      def need_two_factor_authentication?(request)
-        true
+      module InstanceMethodsOnActivation
+        def authenticate_otp(code, options = {})
+          totp = ROTP::TOTP.new(self.otp_column)
+          if drift = options[:drift]
+            totp.verify_with_drift(code, drift)
+          else
+            totp.verify(code)
+          end
+        end
+
+        def otp_code(time = Time.now)
+          ROTP::TOTP.new(self.otp_column).at(time)
+        end
+
+        def provisioning_uri(account = nil)
+          account ||= self.email if self.respond_to?(:email)
+          ROTP::TOTP.new(self.otp_column).provisioning_uri(account)
+        end
+
+        def otp_column
+          self.send(self.class.otp_column_name)
+        end
+
+        def otp_column=(attr)
+          self.send("#{self.class.otp_column_name}=", attr)
+        end
+
       end
 
-      def generate_two_factor_code
-        self.class.login_code_random_pattern.gen
+      def need_two_factor_authentication?(request)
+        true
       end
 
       def send_two_factor_authentication_code(code)