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Redaction and freedom of information

An agency or minister may need to edit material that is exempt under the Freedom of Information Act 1982 (FOI Act) from a document before releasing the document to an applicant. They may need to edit further material from the document before publishing it online in their FOI disclosure log. The process of permanently editing material from a document is known as redaction.

It is important for agencies and ministers to ensure that their chosen redaction method has completely and irrevocably deleted the required material from the released documents. When undertaking redaction, agencies and ministers should also consider their obligations to make online content accessible under the whole-of-government Web Accessibility National Transition Strategy[1] and the Disability Discrimination Act 1992. At the same time, agencies and ministers must ensure that their redaction processes are as efficient as possible to minimise time spent on preparing new versions of documents.

Agencies and ministers will need to undertake their own assessment of the effectiveness, accessibility and other relevant implications of their chosen redaction methods, including ensuring that staff are properly trained to minimise the risk of error. The Office of the Australian Information Commissioner notes that a recent examination by the Defence Signals Directorate (DSD) of the Adobe Acrobat X Pro redaction tools may be a useful resource for agencies and ministers to consider.[2]

Tools for redacting PDF files

Adobe's Acrobat X Pro application, released in November 2010, contains redaction tools for files in portable document format (PDF). Adobe claims that these tools accomplish complete and irrevocable redaction by allowing users to select material requiring redaction from a PDF file and then create a new PDF file for release which duplicates all the content of the original except for the material specified for redaction. Therefore, according to Adobe, the redacted material cannot be retrieved from the resulting PDF file because it never would have existed in that file in the first place.

In November 2011, DSD published An Examination of the Redaction Functionality in Adobe Acrobat Pro. In undertaking their examination, DSD used the Acrobat X Pro redaction tools to redact content from sample PDF files and save the redacted versions as new PDF files for release. DSD then inspected the underlying code of these PDF files to determine if the redacted material was recoverable in any way.

DSD found that the Adobe Acrobat X Pro redaction tools, when used properly, did in fact permanently delete the required material so that it was not present in any form in the final redacted PDF files for release.

It is also worth noting that this kind of electronic redaction process may assist agencies and ministers to meet their accessibility obligations more efficiently than manual redaction. The Acrobat X Pro tools can redact content without converting a PDF file to image format, and can thereby retain existing features of an electronic document that improve its accessibility. By contrast, a document that is printed out, manually redacted and scanned may require additional accessibility optimisation tasks to enhance accessibility.

Further information

Resources to assist agencies and ministers in applying the FOI Act are available at FOI resources.


[1] See the Australian Government Web Guide.

[2] Defence Signals Directorate (2011), An Examination of the Redaction Functionality in Adobe Acrobat Pro.