What Is Redaction? How to Redact Documents, PDFs and Video Properly

Redaction lets an agency, law firm or prosecutor release a record while holding back the parts that could harm someone: a witness's address, a bystander's face, a Social Security number. Done properly, those parts are gone from the file. Done badly, they can be recovered with a copy and paste.

This guide covers what redaction is, why it fails, how to redact documents and video, the US rules that require it, and a checklist.

What is redaction?

Redaction is the removal of sensitive information from a document, image, video or audio recording so the rest can be shared or published. Proper redaction deletes the underlying content, not just its appearance, and usually marks where something was removed, so readers know information was withheld without being able to see or recover it.

Under the Freedom of Information Act (FOIA), federal agencies must release any reasonably segregable portion of a record after deleting the exempt parts. Agencies must also generally indicate how much was deleted and which exemption applies, at the place of each deletion where technically feasible.

Why redaction fails

In December 2005 the National Security Agency published Redacting with Confidence, a guide to sanitizing Word documents converted to PDF. Its central point still holds: information that is only hidden or covered in a computer file can almost always be recovered. The usual failures are:

• Boxes drawn over text. A black box or black highlight hides text on screen but leaves it in the file, where it can be copied and pasted into another document. White text on a white page fails the same way.
• Metadata. Files can carry hidden data such as the author's name, the file's location and the full-size version of a cropped picture. Converting a Word file to PDF doesn't remove all metadata automatically.
• Document history. Word files can keep tracked changes, comments and version information, and earlier revisions and deleted text may be recoverable from a PDF.
• Exhibits and attachments. A September 2026 report to the federal Judicial Conference cited Federal Judicial Center findings that most unredacted Social Security numbers in public filings appear in exhibits and attachments.

How to redact PDFs and documents properly

1. Work on a copy. Keep the original unchanged and save the redacted version under a new name, such as FileName-REDACTED, as the District of New Jersey's e-filing guidance suggests.
2. Remove the content, don't cover it. Delete sensitive text in the source document before converting, or use a PDF redaction tool that removes the underlying text and images.
3. Remove hidden data. Check for and remove comments, tracked changes, document properties, hidden text and attached files.
4. Flatten. Flattening, for example by printing to a new PDF, removes most metadata and interactive features. It is a finishing step, not a substitute for removing the content.
5. Test the result. Search for the words you redacted, copy text across redacted areas into a blank document, and check the file's properties.

Video redaction

Video redaction obscures identifying details in body-worn camera, CCTV, dash-cam and interview footage before it is released or disclosed. Common targets are faces of bystanders, victims, witnesses and minors; license plates; phone, computer and in-car screens; and documents, IDs or house numbers in view.

A blur or solid mask has to follow each target through every frame, including reflections and partial views. Automated detection can find faces and plates, but a person should review the output before release.

Audio redaction mutes or bleeps spoken details such as names, dates of birth, addresses and phone numbers, and captions and transcripts need the same treatment. Keep the original recording unchanged and save the redacted version separately, so the chain of custody for the original is preserved.

Common legal reasons to redact

• FOIA exemptions. 5 U.S.C. 552(b) lists nine exemptions, including (b)(6) for personnel, medical and similar files where release would be a clearly unwarranted invasion of personal privacy, and (b)(7) for law enforcement records where release could cause listed harms, such as revealing a confidential source. State public records laws set their own exemptions.
• Filings. Federal Rule of Civil Procedure 5.2 generally limits personal identifiers in filings to the last four digits of Social Security, taxpayer identification and financial account numbers, the year of birth and a minor's initials. Federal Rule of Criminal Procedure 49.1 does the same in criminal cases and limits home addresses to city and state. Amendments published for public comment in August 2026 would require complete redaction of Social Security and taxpayer identification numbers in civil and criminal filings and pseudonyms instead of initials for minors.
• Privacy laws. Federal and state privacy laws, such as those protecting health and education records, can also require redaction.

Proper redaction vs cosmetic cover-up

Can redaction be undone?

Proper redaction can't be undone from the released file, because the removed content is no longer in it. Cosmetic redaction can: text under a drawn box can be copied out, white text can be recolored, and metadata or earlier revisions can reveal what the visible page hides. The unredacted original still exists, so access to it needs to be controlled and recorded.

Redaction checklist

1. Confirm what the law, rule, order or policy requires you to withhold.
2. Work on a copy and keep the original unchanged.
3. Remove content with a true redaction tool, or delete it at the source.
4. Check headers, footers, footnotes, captions, comments, images, exhibits and attachments.
5. Remove metadata, tracked changes and other hidden data.
6. For video, track every face, plate and screen through each frame, and redact the audio.
7. Mark each redaction and, where required, the exemption relied on.
8. Test by searching, copying and checking file properties, then have a second person review.
9. Record what was redacted, by whom, and what was released.

How DekkoSecure handles redaction

In DekkoCORE, redacting a file makes a separate copy, so the original isn't changed, and recipients can't remove the redactions. See how this works for prosecution disclosure with redactions. For video evidence, DekkoDEMS runs redaction on-device on authorized devices, so source evidence isn't sent to a third-party AI provider. Read more about on-device AI in DekkoDEMS.

Common questions

Frequently Asked Questions