Is my data at nslds secured?
Federal secrecy laws protect the data. The only one who can access NSLDS are those people that need the info to calculate your prospective aid eligibility, or to solve doubts around your loans or grants on a need-to-know basis.

The NSLDS gets it's info from many sources.

The loans and grants listed on the NSLDS website are received from different roots. In general, the authority that approved the financial aid award is responsible for reporting financial aid information to NSLDS. Stafford loans are notifiable by guaranty agencies, Direct loans are notifiable by the Direct Loan Servicing Center, Perkins loans are reported by schools (or their agent), and grants are notifiable by the U.S. Department of Education's Common Origination and Disbursement System.