DLO Security and AD

We have a requirment for DLO 8 and i have a couple of quick questions:

1- What is the possibilty of a user accessing another users backups and getting data of them, for example the admin accessing/browsing another users data and reading it.

2- When the user wants to access their own data, do they authenticate using Active Directory credentials or DLO credentials?

3- Is there a document on how DLO integrates with Active Directroy? and another one that highlights the security levels that DLO offers? A breif about these two areas would be appreciated.

Thanks!