Fundamentals
Anonymizing a document in another language: names, dates and numbers that change
Endings, name order, second spellings, other calendars and other digits hide the same data from a plain search. Learn what changes and how to check any language.
Read articleAnonymization glossary: key terms in English, French and German
Redaction, caviardage, Schwärzung: a three-language reference of 30 terms, grouped by theme, with the official GDPR words and the traps between them.
Read articleWhich Numbers in a Document Are Most Dangerous If They Leak?
A card number, an IBAN and a birth date are not equally dangerous. Here is a harm-based ranking, sourced from official consumer-protection bodies.
Read articleTokenization, Hashing or Encryption: Which One Pseudonymizes?
The words get mixed up in every guide. This article walks through what a counter, a hash, a keyed hash and encryption actually do to a value, and which one fits a document you plan to share.
Read articleWhat Does It Mean to Sanitize a Document?
A lawyer redacting a contract and an IT team blocking a macro are both sanitizing something. They are just not solving the same problem.
Read articleBarcodes and QR codes on documents: what they reveal, and why to mask them
A barcode or QR code often repeats the name, address or account number you just redacted. Here is what common codes contain, and how to check one first.
Read articleLetterheads, headers and footers: the details that identify a document
The body of a letter is not the only place a sender's name hides. Headers, footers and letterheads carry it too, and this guide shows where to look.
Read articleOnline PDF Tools: What Happens to the File You Upload?
When you upload a PDF to an online tool, a copy leaves your device. Here is what that means, what the GDPR requires, and how to avoid it.
Read articleRedaction, Encryption or a Password: Which Protects a Document?
A password, encryption and redaction do not protect a document the same way. Here is what each one really stops, and how to combine them for a safe send.
Read articlePublic, internal, confidential: how classification decides what to mask
Most companies label documents public, internal, confidential or restricted. Here is what each level means, and what to mask before sharing one more widely.
Read articlePII vs personal data: what's the difference between US and EU law?
Americans say PII. Europeans say personal data. The EU definition is wider, and that changes what you should mask in a document before you send it.
Read articleConsistent Pseudonyms: How to Replace Names Without Losing Meaning
A black bar erases a name, and the story around it. Here is how to replace names with consistent, readable labels instead, and keep the label list itself safe.
Read articleWhy Documents Are Harder to Anonymize Than Databases
Deleting a column removes a name from every row at once. A letter has no column, so the same name must be found in the greeting, the address and the signature, one by one.
Read articleHidden data in your documents: metadata, comments and tracked changes
A clean-looking file can still name its author, keep a deleted clause or reveal where a photo was taken. Here is where hidden data lives and how to remove it.
Read articleWhy blacking out text in a PDF often fails
A black rectangle covers text but does not remove it. Here is how hidden words come back, what real redaction does, and how to test your own file.
Read articleAnonymization, pseudonymization, redaction: what is the difference?
Anonymous data leaves the GDPR. Pseudonymized data stays in it, at least for whoever holds the key. Redaction is what you do to the page. Here is how to tell them apart.
Read articleRe-identification: why removing names is not enough
Take the name out of a document and the person is often still there. What gives people away, and a checklist by reader: the public, a colleague, an AI tool.
Read articleWhat counts as personal data in a document? A line-by-line guide
A name is personal data. So is an employee number, a rare job title or a sick-leave date. Here is how to read a contract, a report or a letter line by line.
Read articleWhat is document redaction? Definition, uses and limits
Redaction removes information from a copy of a document for good. Here is what the word means, when the law expects it, a six-step method, and its limits.
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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.