All API access requires that the user is authenticated. Regardless of whether you are using basic authentication (username, password) or going through a token issuer like ADFS, you need to obtain an AccessKey from the API, which is used to authorize access, based on users, groups, access rights and roles. The AccessKey determines what assets and metadata you can access in the DAM Center.

The AccessKey is a guid and refers to a specific user, language and product. The product might be Digizuite™ Media Manager or Digizuite™ DAM For Sitecore - or any other product controlled by the DAM Center. Each product has it’s own set of configuration and in order to access that specific configuration a product specific access key is needed.

Product configuration controlled by the AccessKey:

Specific product configuration that vary by product and by site distribution (e.g. splash screen options in Media Manager)
Configurable searches (think saved searches that are unique per product).
Transcode setup to determine which media formats must be made for a product or channel.
Labels.

You only need to generate an AccessKey for a specific product if you want to access any of the configurations listed above. By default you just need to generate an AccessKey using the "LogOn" method. As the DAM API will be used for this the key returned will refer to the DAM product.

All login specific operations are done using the ConnectService endpoint.
There are two important methods on this endpoint:

LogOn
LogOnWithAccessKeyOptions (use this when in need of product configuration).