Redact PDF — black out private details

How to Redact PDF

1. Choose a PDF, or drop it on the box above. It is searched for private details straight away.
2. Look at what was found and untick anything you want to keep.
3. Add more: type words in Black out these words too and press Find, or drag on the page to draw a box. Check every page with the arrows.
4. Press Black out … and save (it shows how many areas), then Download. Your original file is not changed.

What it finds by itself

When the PDF opens, fixed rules read its text and mark these details. Each one is ticked, with its page, so you can review it:

• Card numbers: 13 to 19 digits that pass the Luhn check payment cards use, so most random long numbers are skipped.
• IBANs that pass the standard mod-97 check.
• Aadhaar numbers that pass Aadhaar’s Verhoeff check digit, PAN numbers by their pattern, and Emirates ID numbers that start with 784.
• The machine-readable lines of a passport page (the lines full of <<<).
• Numbers and dates after a label such as CPR, Civil ID, National ID, Iqama, Passport No., Date of Birth, Account No., Policy No. or Employee ID, and Arabic labels such as الرقم الشخصي, رقم الهوية, الرقم المدني, رقم الإقامة, تاريخ الميلاد and رقم الحساب. The label stays visible; only the value is hidden.
• Names written after a label such as Name, Full name, Father’s name or Patient name, or الاسم, اسم الأب and اسم الأم.
• Phone numbers after a label such as Phone, Mobile or WhatsApp (or الهاتف, الجوال), and numbers written like phone numbers, for example starting with + or 00. Dates and money amounts are left alone.
• Email addresses.

Rules don’t find everything: check every page

Fixed formats with check digits are found reliably. But a name with no label in front of it, an address, a signature, a photo, handwriting or a number inside a picture is not found. Go through every page with the arrows before you save.

For anything else, type it in Black out these words too and press Find; every place it appears is added. The search ignores capital letters. In Arabic it also ignores vowel marks and treats أ, إ, آ and ا as one letter, ى and ي as one, and ة and ه as one, so احمد finds أَحْمَد. For the rest, drag on the page to draw a box. Tap any box to switch it off or on.

How the blacking out works

Laying a black shape over text is not enough: the text is still in the file underneath and can be copied out. This tool does it differently. Every page with at least one box is drawn as a sharp picture (300 dpi), solid black boxes are painted onto that picture, and the picture replaces the page. The hidden text is no longer in the file at all.

What this means for you: on those pages the rest of the text can no longer be selected or searched either. Filled-in form fields and comments on them become part of the picture. Pages without boxes are copied unchanged. The file’s title and author, its bookmarks and its attachments are removed from the whole file. Because some pages become pictures, the new file may be larger. The work happens in your browser; the PDF is not uploaded.

A digitally signed PDF needs a tick first, because any change makes the signature show as invalid.

Scanned pages

A scan is a photo of paper, so it has no text to search. If no page has text, the tool says so and you draw boxes by hand over what to hide. If only some pages are scans, the rules and the search see only the pages with text, so look at the scanned pages yourself and draw boxes there.

Everything happens in your browser: your file is never uploaded to any server. You can check: once your file is open, turn on airplane mode — the tool still works.

Questions

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