Guides
Can ChatGPT or Copilot anonymize a document for you?
ChatGPT and Copilot can rewrite a text with placeholders, but only after they read your unmasked document. Here is what that costs, and the safe order to use them.
Read articleWhat Online PDF Tools Say They Do With Your File: We Read 12 Policies
A dated reading of what 12 online PDF tools say about your uploaded file: deletion times, server locations, DPAs and AI training. We report their words, not tests.
Read articleHow to test a redaction tool before you trust it
Build fictitious test documents, mark the answers first, count what the tool misses and over-masks, then inspect the exported file before you decide.
Read articleHow to redact a PDF on Android
A pen stroke or black highlight on an Android phone only covers the text in a PDF. Here is what each app does, and a one-minute test to run before you share the file.
Read articleShould you hide your signature before sharing a document?
A signature is an image someone can copy, and a digital one hides certificate data in the file. Learn when to keep it visible and when to cover it.
Read articleHow to hide faces and license plates in a photo before sharing it
Blur is not enough to hide a face or a plate. Here is what else in a photo can identify someone, and how to cover it before you share.
Read articlePosting a Document Online to Ask for Advice: What to Mask First
A tenant posts a fine online and asks: is this normal? Here is what to black out first, and what to leave so strangers can actually help.
Read articlePublishing a PDF on your website: what search engines can read in it
Google reads the text inside a PDF, not just its file name. Here is what it can see, how to test a file first, and how to pull one back.
Read articleSharing a Medical Certificate: What the Recipient May See
Your employer almost never sees your diagnosis. Here is what each country's sick note actually contains, and what you can safely hide on the documents you choose to share.
Read articleHow to Anonymize a Manuscript for Double-Blind Peer Review
Journals ask for more than a deleted name. Names hide in acknowledgements, self-citations, and the file's own hidden properties. Here is what to check before you submit.
Read articleGenealogy: sharing old civil records without exposing living people
The dead are outside the GDPR, but the living relatives named on the same page are not. A country-by-country guide to what becomes public, and what to mask first.
Read articleTranslating a confidential document: what to mask before you use a translator
An online translator can turn a private document into cloud data in seconds. Here is what to mask first, and when only a certified human translator will do.
Read articleHow to Redact a PDF on Windows
Highlighting text in Edge does not redact a PDF. See what Adobe Acrobat and LibreOffice Draw actually remove, and how to test a redaction before you send it.
Read articleHow to Turn a Signed Contract Into a Reusable Template Without Leaking the Client
A signed contract makes a great starting point for your next deal, if you strip it right. Here is where client data hides, and how to check it is really gone.
Read articleAnonymizing an internship report or thesis: what to hide
Client names, exact figures, screenshots of internal tools: a report about a real company needs care. Here is what to hide, how, and when a formal confidentiality procedure applies instead.
Read articleHow to anonymize a slide deck before you share it
A slide deck carries more than its slides: notes, hidden slides, comments and file properties can travel with it. Here is where they hide and how to clear them before you share.
Read articleHow to Anonymize a Filled-In PDF Form (and Why the Answers Can Survive)
Typed answers, checkboxes, and comments can survive a black box on a PDF form. Here is what is really inside the file, and how to check before you send it.
Read articleHow to anonymize meeting minutes before sharing them
Minutes name people, quote them, and record votes. Before you share or publish them, learn what to keep private and how a two-version method works.
Read articleHow to Redact a PDF Without Adobe Acrobat
Adobe Acrobat is not the only way to redact a PDF. macOS Preview and LibreOffice Draw both remove text for good, if you use them the right way.
Read articleHow to redact a PDF on a Mac, iPhone, or iPad
A black shape drawn in Markup only sits on top of the page. See what Preview's Redaction Selection tool really removes, and a short test to run before you send a PDF.
Read articleHow to share a copy of your ID card safely
Landlords, banks and websites ask for ID copies. What you must show, what you can cover, and how a purpose watermark limits the damage if a copy leaks.
Read articleHow to redact a Google Docs document before sharing
Google Docs has no redaction tool. Here is the safe order: clean version history and comments, download the file, then mask the sensitive text for good.
Read articleHow to anonymize an email thread before forwarding or archiving it
A practical routine for cleaning an email thread before you forward it or file it away: trim the history, handle attachments, then redact the PDF.
Read articleHow to anonymize a Word document before sharing it
Tracked changes, comments, headers, embedded spreadsheets: a Word file holds more than the page shows. Here is the order to clean it, label names and export safely.
Read articleHow to redact a PDF properly: a step-by-step guide
Covering a name with a black shape leaves the text in the file. Here are the routes that really remove it, and a short routine to test your PDF before you send it.
Read articleWhat to mask before you upload a document to an AI assistant
A practical guide to what to mask in a contract, a CV, a medical letter or a log file before an AI assistant reads it, with a table and a checklist.
Read articleHow to redact a scanned document or a photo of a page
A scanned page is an image. Here is how to find its text with OCR, mask what OCR misses, remove hidden text layers and check the file you send.
Read articleBlur or black box? How to hide text in a screenshot safely
Researchers have read pixelated and blurred text again. A solid box, a flattened export and a new file keep a screenshot private. Here is the routine.
Read articleHow to check a redacted document before you send it: a 10-minute routine
A black bar can hide nothing at all. Run these six quick tests on any redacted file before you hit send, then print the checklist.
Read articleSharing a sensitive document safely: a practical checklist
A short checklist for any job: what to leave out, what to mask, which channel to pick, how to check the recipient, and what to write down once the file is gone.
Read article
Mask a document without uploading it
ONYRI Sanitize finds names, identifiers, bank details and secrets in a PDF, a Word file or a scan, and masks them in your browser. You check the preview, then download a flattened copy.