# Two factor authentication for Devise

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## Features

* control sms code pattern
* configure max login attempts
* per user level control if he really need two factor authentication
* your own sms logic

## Configuration

### Initial Setup

In a Rails environment, require the gem in your Gemfile:

    gem 'two_factor_authentication'

Once that's done, run:

    bundle install

### Automatic installation

In order to add two factor authorisation to a model, run the command:

    bundle exec rails g two_factor_authentication MODEL

Where MODEL is your model name (e.g. User or Admin). This generator will add `:two_factor_authenticatable` to your model
and create a migration in `db/migrate/`, which will add `:otp_secret_key` and `:second_factor_attempts_count` to your table.
Finally, run the migration with:

    bundle exec rake db:migrate

Add the following line to your model to fully enable two-factor auth:

    has_one_time_password

Set config values, if desired, for maximum second factor attempts count, allowed time drift, and OTP length.

```ruby
config.max_login_attempts = 3
config.allowed_otp_drift_seconds = 30
config.otp_length = 6
```

Override the method to send one-time passwords in your model, this is automatically called when a user logs in:

```ruby
def send_two_factor_authentication_code
  # use Model#otp_code and send via SMS, etc.
end
```

### Manual installation

To manually enable two factor authentication for the User model, you should add two_factor_authentication to your devise line, like:

```ruby
devise :database_authenticatable, :registerable,
       :recoverable, :rememberable, :trackable, :validatable, :two_factor_authenticatable
```

Add the following line to your model to fully enable two-factor auth:

    has_one_time_password

Set config values, if desired, for maximum second factor attempts count, allowed time drift, and OTP length.

```ruby
config.max_login_attempts = 3
config.allowed_otp_drift_seconds = 30
config.otp_length = 6
```

Override the method to send one-time passwords in your model, this is automatically called when a user logs in:

```ruby
def send_two_factor_authentication_code
  # use Model#otp_code and send via SMS, etc.
end
```


### Customisation and Usage

By default second factor authentication enabled for each user, you can change it with this method in your User model:

```ruby
def need_two_factor_authentication?(request)
  request.ip != '127.0.0.1'
end
```

this will disable two factor authentication for local users

This gem is compatible with Google Authenticator (https://support.google.com/accounts/answer/1066447?hl=en).  You can generate provisioning uris by invoking the following method on your model:

    user.provisioning_uri #This assumes a user model with an email attributes

This provisioning uri can then be turned in to a QR code if desired so that users may add the app to Google Authenticator easily.  Once this is done they may retrieve a one-time password directly from the Google Authenticator app as well as through whatever method you define in `send_two_factor_authentication_code`

#### Overriding the view

The default view that shows the form can be overridden by first adding a folder named: "two_factor_authentication" inside "app/views/devise", in here you want to create a "show.html.erb" view.

The full path should be "app/views/devise/two_factor_authentication/show.html.erb"

```html
<h2>Hi, you received a code by email, please enter it below, thanks!</h2>

<%= form_tag([resource_name, :two_factor_authentication], :method => :put) do %>
  <%= text_field_tag :code %>
  <%= submit_tag "Log in!" %>
<% end %>

<%= link_to "Sign out", destroy_user_session_path, :method => :delete %>

```

#### Updating existing users with OTP secret key

If you have existing users that needs to be provided with a OTP secret key, so they can take benefit of the two factor authentication, create a rake. It could look like this one below:

```ruby
desc "rake task to update users with otp secret key"
task :update_users_with_otp_secret_key  => :environment do
	users = User.all

	users.each do |user|
		key = ROTP::Base32.random_base32
		user.update_attributes(:otp_secret_key => key)
		user.save
		puts "Rake[:update_users_with_otp_secret_key] => User '#{user.email}' OTP secret key set to '#{key}'"
	end
end
```

### Example

[TwoFactorAuthenticationExample](https://github.com/Houdini/TwoFactorAuthenticationExample)