Can I bypass oAuth for Adobe if we are already using a third authentication service like Okta?

Hi,

In our application we are already authenticating our clients using Okta for using our application.

But for signing the documents if we ask users to sign, they might feel overwhelmed. Is there any silent way to authenticate users not growing the same process? 

I do know there is an option called "INTEGERATION KEY" which doesn't need oauth process?

I need a guidance in this .