A Black Box Is Not Redaction
Drawing a black rectangle over text hides it on screen and nothing more. The words are usually still in the file, so anyone can select, copy or search them, and redaction failures in published documents have often happened exactly this way. Real redaction removes the content itself.
BoostPDF's Redact tool works in two steps. First you mark what must go: marks show in red and change nothing yet. Then you create a released PDF, a new file where the text, picture parts and shapes under each mark have been removed, with black boxes showing where. Comments, form data, document details, bookmarks and attachments are left out, and the file is checked before you download it.
In short: Load your PDF, mark text by dragging over it or use Find & redact to list ID numbers, names and emails, give each mark a withholding ground if you need one, then choose Create released PDF. You get a new file with the marked content gone and the result checked.
Redacting Social Security, Social Insurance and National Insurance Numbers
These are the numbers most often left in documents by mistake, and a black box over them is not enough. Find & redact lists every match in the document so you can mark them in one go. For the United States it looks for Social Security numbers and ITINs; for Canada, Social Insurance numbers; for the United Kingdom, National Insurance numbers and NHS numbers. Social Security numbers and National Insurance numbers are ticked the first time you open their country; ITINs and NHS numbers you tick yourself.
Some matches will be ordinary numbers that only look like one. Every match is listed to tick or untick before anything is marked, and you can still drag a box over anything it misses. Then create the released PDF: the numbers are removed from the file, not covered.
Workflow: Mark, Label, Release, Check
- Load the Document: Open your PDF in the BoostPDF editor with the Redact tool already selected. The file opens on your device and is not uploaded.
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Mark What Must Go:
Drag across text to mark it, or double-click a word. Where there is no text, such as a signature or a picture, drag a box. To search every page at once, open Find & redact:
- Words or names, one per line, such as a person or a hospital.
- Each country's ID numbers (such as Social Security, Social Insurance, National Insurance, IRD, T.C. Kimlik or My Number) and phone numbers, plus email addresses and IBAN bank accounts. You tick which matches to mark.
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Give Each Mark a Ground (Optional):
Pick the law's list of withholding grounds, then the ground for new marks. You can change any mark's ground later or add your own grounds.
- United States: Freedom of Information Act and Privacy Act of 1974. Canada: Access to Information Act and Privacy Act.
- New Zealand: Official Information Act 1982, LGOIMA 1987 and Privacy Act 2020. Australia: Freedom of Information Act 1982.
- Create the Released PDF: Review your marks, name the file and choose Create released PDF. You can show each ground on its black box. The document in the editor keeps its marks, so you can adjust and release again.
- Check and Download: The file is checked before you get it: no letters are left under any mark, and nothing outside the boxes has changed. If a page fails the check, the release stops and names the page.
What the Released PDF Removes
Redaction is only as good as what is left behind. The released PDF is built to leave nothing under your marks:
Text Under the Marks
Removed from the file, so it cannot be selected, copied or found with search.
Pictures and Shapes
Picture parts and shapes under a mark are cut out, not hidden beneath a box.
Hidden Extras
Comments, form data, document details, bookmarks, attachments and scripts are left out of the new file.
Automatic Check
Before download, the file is checked for letters left inside the boxes and for changes outside them. A failure stops the release and names the page.
Your Original Stays Intact
The released PDF is a separate new file. The document in the editor keeps its marks, so you can adjust them and release again.
Find & Redact: Names, Emails and ID Numbers
Find & redact searches every page at once, on your device. Type words or names, one per line, or pick a country to list its ID numbers. The ones that most often turn up are ticked the first time you open that country; you tick the rest yourself. Every match is shown before anything is marked.
| Country | ID numbers it finds |
|---|---|
| United States | Social Security numbers, ITINs |
| United Kingdom | National Insurance numbers, NHS numbers |
| Canada | Social Insurance numbers |
| Australia | Tax file numbers, Medicare numbers |
| New Zealand | IRD numbers, NHI numbers, bank account numbers, driver licence numbers |
| France | Numéro de sécurité sociale, numéro fiscal |
| Germany | Steuer-ID |
| Spain | DNI and NIE numbers |
| Mexico | CURP (Clave Única de Registro de Población) |
| Japan | My Number (マイナンバー・個人番号) |
| South Korea | Resident registration numbers (주민등록번호), foreigner registration numbers |
| Thailand | National ID numbers (เลขประจำตัวประชาชน) |
| Türkiye | T.C. Kimlik numbers |
Email addresses and IBAN bank accounts are found whichever country you pick, and phone numbers are covered for most countries.
Scanned pages need OCR first so their text can be found. Where there is no text, drag a box over the area instead.
Withholding Grounds for FOIA, Access to Information and Privacy Requests
When you release information in response to a request, you usually have to say why parts were withheld. Choose a law's list in the Redact tool and each mark carries a ground, which can be shown on its black box. The most commonly cited grounds are listed first.
United States: FOIA and Privacy Act of 1974
FOIA exemptions (b)(1) to (b)(9), with the most cited first: (b)(6) and (b)(7)(C) personal privacy, (b)(7)(E) law enforcement techniques and (b)(5) deliberative process. For requests for your own records, the Privacy Act list adds the (d)(5), (j) and (k) exemptions.
Canada: Access to Information Act and Privacy Act
Access to Information Act sections such as s.19(1) personal information, s.17 safety of individuals, s.15(1) international affairs and defence and s.21 advice or recommendations. For personal information requests, Privacy Act sections such as s.26 information about another individual.
New Zealand: OIA, LGOIMA and Privacy Act 2020
Official Information Act 1982 sections 6 and 9, such as s9(2)(a) privacy of natural persons and s9(2)(g)(i) free and frank expression of opinions. LGOIMA 1987 sections 6 and 7 for local government, and Privacy Act 2020 grounds for refusing access, plus "Out of scope".
Australia: Freedom of Information Act 1982
Exemptions such as s47F personal privacy, s47E(d) proper and efficient conduct of an agency's operations, s47C deliberative processes and s22 irrelevant material (edited copy).
The descriptions are short labels, not the Acts' own wording, and the lists were last checked against the Acts in October 2026. Another country, or an agency with sections of its own? Add grounds of your own and use them like the built-in lists. Check each use against the law that applies to you. Marks without a ground can still be released.
Privacy and Security
Redacting means handling the documents you least want exposed, so the tool is built to keep them on your device:
Nothing Is Uploaded
Marking, searching and creating the released PDF all happen in your browser. Your file is never sent to our servers.
Local Redaction Engine
The engine is a WebAssembly module that is loaded only when you use it and runs inside your browser.
Review Before Release
Marks change nothing until you create the released PDF, so you can review every mark and its ground first.
Share the Released File Only
The document with its marks still holds everything you removed. Keep it inside your organisation and share the released PDF.
Know the Limits
Scans: Scanned pages have no text to search. Run OCR first if you want Find & redact to work on them, or drag boxes over the scanned content.
Matches are a start: Find & redact finds numbers that fit a country's pattern. A mistyped number, or one split across two lines, can be missed, and some matches are ordinary numbers. Check every page, and drag a box over anything it misses.
Look before you share: BoostPDF checks the file, but you decide what needs redacting. Open the released PDF and look at it before you send it.
Not legal advice: BoostPDF is a pdf editor, not legal advice or certification. The ground lists are labels to help you; confirm them against the law that applies to you.
Frequently Asked Questions
Is the text under the black box really gone?
Yes. In the released PDF, the text, picture parts and shapes under each mark are removed from the file, not covered. The file is then checked for any letters left in the boxes. Until you create the released PDF, marks are only marks, so share the released file, not the marked one.
Is my PDF uploaded to your servers?
No. Searching, marking and creating the released PDF all happen in your browser, on your device.
How do I redact a Social Security number from a PDF?
Open the PDF in the Redact tool, choose Find & redact and pick United States. Social Security numbers are ticked at first. Every match is listed: untick any that are not Social Security numbers, mark the rest, then choose Create released PDF. The numbers are removed from the file, not covered.
Which countries' ID numbers can it find?
Thirteen: the United States, United Kingdom, Canada, Australia, New Zealand, France, Germany, Spain, Mexico, Japan, South Korea, Thailand and Türkiye. Email addresses and IBAN bank accounts are found whichever country you pick. Where a number has a built-in check, it is verified, which cuts false matches.
Can I record why information was withheld?
Yes. Pick the list for your law: the US FOIA or Privacy Act of 1974, Canada's Access to Information Act or Privacy Act, New Zealand's Official Information Act, LGOIMA or Privacy Act 2020, or Australia's FOI Act 1982. Each mark gets a ground that you can show on its black box. You can also add your own grounds.
Does it work on scanned PDFs?
Scanned pages have no text to search, so run OCR first if you want Find & redact to work on them. You can always drag a box over any part of a page, scanned or not.
Will Find & redact catch every number?
Not necessarily. It finds numbers that fit each country's pattern, and every match is shown for you to tick or untick. A mistyped number, or one split across lines, can be missed, so look through the pages and drag a box over anything it did not find.
Is this suitable for legal or compliance redaction?
It is built to remove content properly and to record grounds, but it is not legal advice or certification. Review the released PDF and confirm the grounds against the law that applies to you.