# Two factor authentication for Devise
[](https://travis-ci.org/Houdini/two_factor_authentication)
[](https://codeclimate.com/github/Houdini/two_factor_authentication)
## 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 and allowed time drift for one-time passwords:
```ruby
config.max_login_attempts = 3
config.allowed_otp_drift_seconds = 30
```
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 and allowed time drift for one-time passwords:
```ruby
config.max_login_attempts = 3
config.allowed_otp_drift_seconds = 30
```
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`
### Example
[TwoFactorAuthenticationExample ](https://github.com/Houdini/TwoFactorAuthenticationExample )
