This old backup: how to dispose of your old archives without exposing yourself
March 31 is World Backup Day, the day that the storage tech industry exhorts us all to back up our digital possessions and practice good data hygiene. But there’s one thing that’s just as important as backing up your data in the first place, or possibly more so: properly getting rid of your old backups when they’re no longer useful. So while you’re using today as an excuse to get your friends and family to get their critical files backed up, it’s worth taking a hard look at how to make sure that old backups get retired in a way that doesn’t result in someone getting hold of your grandmother’s tax return.
Backups, like anything in a can, have a limited shelf life. Just as you should destroy those old bank statements, pay stubs and other pieces of paper that have your personal data on them, old data needs to be shredded too—virtually or physically. Just like you’d never give your tax returns to your kid’s school for origami projects, you shouldn’t just pass on that old 200 GB external drive to your cousin—or sell it on Craigslist—without taking some precautions first.
There are plenty of cautionary tales of disk reuse gone wrong. In 2009, researchers surveying used hard disks found sensitive data on an antiballistic missile system and the Lockheed-Martin facility where it was being developed on a hard drive purchased on eBay. And last year, a survey of drives being prepared to be sold at auction by the State of New Jersey found court records and other sensitive data still lingered on the drives.