The integration of the HAS protocol in existing Private Key Storage Applications (PKSA) such as Hive Keychain Mobile or HiveWallet is well underway.

If you wish to integrate and test HAS in your (d)App, you can request access to the beta version of Keychain Mobile with HAS support on their discord server.

Playing with HiveWallet will take a bit longer because @roelandp recently learned that a few libraries he was using are now discontinued. A bit more work for him before releasing a new HAS compatible version.

In the meantime, you might be interested in running your own PKSA so that you can perform your tests in a safe and peaceful environment.

1. PKSA with a User Interface

Developing a PKSA with a user interface can be seen as reinventing the wheel since applications like Keychain Mobile or HiveWallet already exist and will soon be available with full HAS support.

Nevertheless, you might not trust them and want to use your own PKSA.

However, the source code of these two applications being open-sourced, the easiest way to create your own PKSA with a UI is to draw inspiration from it.

If you are in a hurry and do not want to wait, you can create your own user interface, integrate the PKSA service mode code described below and implement user interactions where indicated in the source code.

2. PKSA in Service Mode

A "Service Mode" PKSA is software without a user interface running on a computer connected to the internet and waiting for authentication and transactions requests.

Depending on how you configure it, it can register the account(s) you want it to manage without processing an offline authentication payload.

From then, the applications you use will have to connect to the same HAS server as your PKSA to be able to communicate with it.

Your PKSA can then store and provide your App(s) with a valid authentication token. It can also (automatically) approve transactions requests coming from your App if you enable it to do so.

https://docs.hiveauth.com