In my university they gave sequential IP addresses and phone numbers to all the room, I combined this data with our uni LDAP system, so I could go from any iden

In my university they gave sequential IP addresses and phone numbers to all the room, I combined this data with our uni LDAP system, so I could go from any identifier (photo, email, name, room number, telephone number, ip address) to any other identifier. It's was more for a fun hack than anything else, but it raised the issue that from someones IP address you could figure out who they were and where they lived, so my uni ended up changing IP allocation procedure sometime after that. Also as a side effect I found a number of "black holes" in the LDAP system that queries for certain users returned a null result, after going through the list by hand I figured out that they were "VIP" students (typically sons/daughters of the powerful/famous) - it turned out that by merging the data sets in the way I had, I'd also built a system that highlighted the personal details of the "secret" students, the exact opposite of what the university had intended.