Author Enabled, JSON Web Tokens and AEM.

Has anyone created JSON Web Tokens from an authenticated user in AEM? Say for example, we have a external application that creates a authoring experience for CRUDing content fragments in AEM. We want to create a login experience in this external application, where once the user is logged in, we can obtain the JSON Web Token, so we can again interact with the AEM authoring environment.
How can we do this?