How to Hide an ID Number or Personal Details in a PDF
Sending a payslip to a landlord, a bank statement to an accountant, or a medical summary to an insurer? Most documents carry more personal details than the recipient actually needs. Here's how to hide them properly, and why a black rectangle drawn in an editor usually isn't enough.
What's worth hiding
There's no single rule, but these are the details worth pausing on to ask "does the recipient need this?":
- ID number. The easiest detail to misuse, especially together with a name and date of birth.
- Bank account and credit card numbers.
- Home address and phone number, when they aren't relevant.
- Medical details unrelated to the claim or request.
- Account transactions that have nothing to do with the matter, for example when you only need to show that your salary comes in.
Before hiding anything, check what the organization actually needs. A bank reviewing a loan application will probably need your ID number, and a redacted document will only delay things.
The common mistake: covering instead of removing
The intuitive approach is to open the PDF in an editor and draw a black box over the detail. On screen it looks perfect. But in most cases the box just sits on top of the text, and the text itself is still in the file. Anyone who receives the document can:
- Select the area and copy the hidden text.
- Search the file and find it.
- Delete the box in an editor.
This isn't theoretical. Documents from large organizations have leaked exactly this way. Real redaction removes the text from the file and leaves only the box.
How to redact properly
- Open Redact PDF.
- Upload the document.
- Type the details to hide, separated by commas. For example:
123456782, 12-345-678901. - Download the file.
The tool finds every occurrence of the text on every page, removes it, and replaces it with a black box.
Tips for a complete result
- Type it exactly as it appears. If the ID shows as
12345678-2, type it that way. If it appears in two forms, enter both. - Think about other occurrences. A name can appear in the header, the address and the signature. An account number may appear with dashes in one place and without in another.
- Check the result. Open the file, press Ctrl+F and search for what you hid. If nothing is found, it worked.
Scanned documents
A scan is an image, so there's no text for the tool to find. The fix: first run the scan through OCR with the Searchable PDF output, then redact the result.
Extra layers of protection
Redaction is the key step, but it combines well with two other tools: