Thursday, August 04, 2005

MS Office 2003 Redaction tool

I got an email this morning about a tool released by MS called the "Office 2003 Redaction Tool". This tool is an Office 2003 add-in that allows you to redact documents.

Now, many of us are aware of issues with redaction, as well as with metadata in Office documents in general. In the past, folks have posted "redacted" PDF documents to the web, only to have someone with a slow download speed find out that the redaction was...well...not a good as expected. Talk about low-tech! Some of the earliest issues I'm aware of involved someone downloading a PDF document, and then being surprised when, through a slow link, serveral words were suddenly replaced with black blocks! Hey! In a nutshell, it simply took a few more seconds for the redaction blocks to crawl through the link and make their appearance on the page. At that point, all the reader had to do was remove the blocks.

So, I downloaded and installed the redaction tool, and opened up a small document I have on my desktop. I redacted two unique words in the document, and saved the resulting document. I then opened the resulting document in a hex editor and found that in hex, the redacted words had been replaced by "7C". Wow.

This is simply an initial test. There's lots more to do. For example, it appears that the redaction tool also looks in the document properties (ie, metadata) for the same redacted words...I say "appears" because I don't know for sure yet.

Something else to consider is this...let's say that you have a Word document, and in the interests of national security, you need to redact the phrase "small happy dog". Now, let's then assume that you have the phrase "I'm really happy about my job" in the comments (metadata) for the document.

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