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 an RSA-based token that is used to identify the underlying user. The accesskey must be parsed for all requests going to the Digizuite API either in the Authorization header or as a query parameters
Authorization: AccessKey <accesskey>https://request url.com/someparameter?accessKey=<accesskey>
To login see the below documentation