What is DLP?
Data Loss Prevention, told as a story about red-stamped papers.
Some papers must never leave the castle.The resident list, the treasure map, the secret letter. Each carries a red stamp.
Papers leave by many roads.Mail, bags, pigeons… and far more of it is by mistake than by theft.
DLP checks every paper at every way out.A red stamp, or a number shaped like an ID: it stops.
Block it, ask, or seal it.One 'Really send this?' removes most of the mistakes. And it all goes in the ledger.
Stop people too often and they go around you.Block the lunch menu and people find another road. And an unstamped page, or a photo of one, slips right past.
DLP = stamp the secret papers, then check every way out so they don't leak.
Data Loss Prevention. It catches mistakes far more than thieves. Think Microsoft Purview, Google Workspace DLP, Symantec DLP.
When grown-ups say it
- Classification
- The red stamp. Public / internal / secret. Only stamped papers get recognized at the ways out.
- Pattern / fingerprint
- Number shapes. ID and card numbers have a fixed shape, so they're caught even without a stamp.
- Channel / egress
- The ways out. Email, USB, cloud upload, printing, screen sharing.
- Endpoint DLP
- Checking the bag. Watches inside the laptop. → a dog in every room
- Network DLP
- Checking at the gate. Watches the road out. → the hallway watcher
- Policy
- What, and how. "secret stamp + mail = block", "card number + mail = ask".
- False positive
- Blocking the lunch menu. Stopped, but not secret. Too many and people route around you. → the guard room's cat
- Shadow channels
- Photos, personal mail. The roads nobody watches — where DLP is blind.