You can add additional security to your APIs in several ways:
Create TLS profiles to secure transmission of data,
Authenticate and secure your APIs with a User Registry,
Configure an OAuth Provider,
Add a Security Definition using API Key, Basic Auth or OAuth.
API Connect allows you to securely authenticate your Catalogs and APIs by adding a Security and Security Definitions section to your API. One of the options for a Security Definition is to add OAuth Open ID Connect from a 3rd party provider.