OneTaskBy Tim King · Updated
Redaction Checker
Names and Numbers Still Readable Under Black Boxes in a PDF
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How the Redaction Checker works
This redaction checker finds personal details still readable in a document that was meant to be redacted. Select all the text in the PDF or file, copy it, and paste it here. Anything that should have been hidden but comes out as text is flagged line by line.
Why a redaction checker is needed
The most common redaction mistake is drawing a black rectangle over text. It looks hidden on screen and in print, but the words are still in the file underneath, and anyone can select and copy them. Court filings and government releases have exposed names this way many times.
Copying the text out is the quickest test. If a redaction worked, the hidden words are gone from what you paste. The checker scans that text for emails, phone numbers, card numbers that pass the Luhn check, US Social Security and UK National Insurance numbers, IBANs, UK postcodes, dates and IP addresses. Add the names or words that were meant to be hidden and it searches for those too.
It also counts black-box characters such as █ that were typed rather than drawn, and markers like [REDACTED]. The tool flags what it can see, it cannot certify a document as clean. Use a proper redaction feature that removes the text, then check again.
FAQ
How do I copy the text out of a PDF?
Open the PDF, press Ctrl+A or Cmd+A to select everything, then copy and paste it here. If nothing selects, the pages may be scanned images, and then you need to check the images themselves.
Is the document text uploaded?
No. The checks run in your browser with JavaScript and nothing is sent or stored. That is important, because the text you paste is exactly the sensitive material the redaction was meant to protect.
Nothing was found. Is the document safe to publish?
Not necessarily. The checker looks for common formats and the words you list, so an address, job title or case detail can still identify someone. Also check the metadata, comments and any hidden layers.
Why are dates and postcodes flagged?
A date of birth or a postcode can identify a person when combined with other details. Some dates in a document are meant to be public, so look at each flagged line and decide whether it should be hidden.
See also: all Security & Identifiers tools, Dev Utilities, Formatters & Validators, Data & Encoding, SEO, Accessibility, AI.
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