Only enterprise user needs to register your device.
You can skip registering your device if you don't need it.

The IIJ SmartKey app produces one-time passwords that conform to TOTP (RFC 6238) standards and can be used in the 2-step verification authentication processes of a variety of online services supporting TOTP.
Strengthen your online service security by linking this app installed to your smartphone device with your ID/password verification processes.

Slide authentication can be used (ver 2.0).
When logging in to a service that supports slide authentication you will receive a push notification on your smartphone. Then you can pull the service icon for 2-step verification.
For details please visit http://www.iij.ad.jp/biz/smartkey-m/ .
* To use slide authentication you must register your device.
* Slide authentication requires support for TLS 1.2 or later. Please use Android 5.0 or newer.

■ Special Features
* Protects against unauthorized access by allowing the user to lock the app using a passcode.
* Supports device changes and data backups by handing over settings between devices.
* Compatible with the Google Authenticator (TOTP authentication).
* Supports slide authentication.
* Easy to see and read simple and refined design.

■ Confirmed Supported Services (TOTP authentications)
* Amazon Web Services
* Dropbox
* Evernote
* Facebook
* GitHub
* Google Accounts
* Google Apps for Work
* IIJ Omnibus
* IIJ Secure MX Service
* Microsoft Accounts
* Slack
* WordPress.com

■ Confirmed Supported Services (Slide authentications)
* Additional details on available services is expected soon.

■■ Please make sure to read the information below before using the app.
* When switching devices please check the app help page (https://www1.auth.iij.jp/) before transferring service settings from your old device to the new one.
* Please ensure that you confirm service restoration procedures for the various online services you utilize in advance to protect yourself against cases in which you are unable to complete the 2-step verification process due to device loss or accidental deletion of service settings.

■ User Agreement
All users of this app must consent to the User Agreement found below before using the app.
https://www1.auth.iij.jp/smartkey/agreement_v2.html

■ To Service Providers
If you are considering adding slide authentication to your service please inquire through the URL below.


-----
Mentioned company names and service names are the trademarks or registered trademarks of their respective companies.