An estate agent asks for proof of income for a rental. The document carries your identity number, your address, your date of birth and your salary. The agent does not need all of that — but sending the document as it is happens to be the easiest thing to do, so most people do exactly that. Once those details are out, they cannot be pulled back.
The most common mistake: drawing a black box
Most people do this in a PDF viewer by drawing a black rectangle over the detail. On screen the information disappears and the job looks done.
It is not. A box drawn on a PDF is a shape added ON TOP of the document; the text underneath stays exactly where it was. If the recipient selects that area with the mouse and copies it, your identity number comes out intact. Selecting and copying text takes no technical skill at all.
Test it on your own document: select the area you covered, copy it, and paste into a text box. If the information appears, you have not redacted it — you have merely covered it.
The same flaw applies to white boxes, highlighter strokes and images pasted over text. Invisible is not the same as deleted.
The right method: take the data out of the document
Real redaction removes the text from inside the document. Nothing remains in the covered area to copy, and searching returns nothing either.
- Add the document: Give the PDF to the redaction tool. If the text is searchable in the document, it works directly.
- Choose what to remove: Patterned data such as identity numbers, phone numbers and bank account numbers is found automatically. Tick the ones you want removed.
- Check and download: Your selections are stripped out of the document. In the downloaded file, try selecting and copying those areas — nothing should come out.
Scanned documents behave differently
If your document was scanned or photographed, the writing inside it is really an image; there is no selectable text layer. That is both good and bad news.
The good: the text cannot be copied anyway. The bad: it is still readable by eye, so you still need to cover it, and the covering has to be applied to the image itself. With such a document, zoom into the redacted area in the downloaded file to confirm it is genuinely covered.
What to hide and what to leave
Over-redacting makes a document useless; under-redacting does not protect you. A practical rule: anything the recipient does not need for the task at hand can be hidden.
- For a government body: usually hide nothing. They will verify your identity, and an incomplete document gets rejected.
- For an employer: the identity number is often required, but family details, home address and health data usually are not.
- For private parties such as agents, sellers or websites: identity number and date of birth are almost never needed.
- For anything you will post publicly: do not share the document at all. Even a redacted document carries details that can identify you.
Consider splitting before redacting
Sometimes the cleanest answer is not to redact but to send only the page that matters. Rather than sharing an eight-page statement with six pages blacked out, pull out the single relevant page and send that. It is both safer and more considerate.
Extracting one page takes seconds, and it makes the recipient's job easier too.