ISO/IEC 27038: what the digital redaction standard asks
There is an international standard for digital redaction: ISO/IEC 27038, “Specification for digital redaction”. If your data protection officer or IT team is weighing a redaction tool, it’s the yardstick to ask about. Its subject is secure redaction, which comes down to two conditions: what’s removed can’t be recovered, and nothing stays hidden in the file. Here’s what the standard covers, going by its public summary, what that means for a tool, how we assessed Dress Docs against it, and the tests you can run without taking anyone’s word for it.
What ISO/IEC 27038 covers
ISO and IEC published ISO/IEC 27038 in 2014. Its public abstract says three things. It specifies characteristics of techniques for performing digital redaction on digital documents. It specifies requirements for software redaction tools and methods of testing that digital redaction has been securely completed. And it does not cover redacting information from databases.
The full text is sold by ISO. This article goes only by the public abstract and by what a secure redaction has to achieve; it doesn’t quote or summarize the paid text.
Removed means not recoverable
A redaction is secure only if the removed content is no longer in the file. A black box drawn over live text fails that test, because the text is still underneath (why a black box isn’t enough). So do blur and pixelation, which disguise content instead of removing it.
In Dress Docs, each exported page is one flat image with the covers in it, so nothing under a cover is written to the file. Covers are solid; there is no blur or pixelation.
Nothing in the parts you can’t see
A file carries more than its visible page. Metadata, hidden text, layers, annotations and form fields can all hold what the page no longer shows. The UK’s ICO treats this as its own risk in its guidance on disclosing documents securely, next to redaction itself.
A Dress Docs export has no text layer, annotations, form fields or layers. Author, title, producer, creator, dates and the PDF’s document ID are cleared, and image metadata from the original is not carried over. More on that: remove metadata from a PDF.
Our self-assessment
We assessed Dress Docs against ISO/IEC 27038 ourselves; it is self-assessed, not certified, and no third party has audited it. The requirement-by-requirement table is in the compliance pack: redaction method.
Run the tests yourself
The abstract says the standard includes methods for testing that a redaction has been securely completed. You don’t need the paid text to run the basic checks on any export:
Dress Docs also shows its own check after every export: no text layer, metadata empty, for the file you just made.
Weighing more than the method? The full set of questions to ask any redaction tool, and where we answer each one: approving a redaction tool. Or go straight to the compliance pack.