How Not to Redact a Document, Part 2

Last year I made a post about How Not To Redact a Document, in which I showed some digitally redacted documents can have have the redaction removed by simply highlighting the redacted text.

Unfortunately, digitally redacted documents aren't the only ones susceptible to attack.

Recently the IRS has come under fire for sending to Tea Party groups probing letters threatening their non-profit status unless they answer a large number of questions.

Fox News redacted parts of the letter, as you can see below.

However, Fox News really failed at their redaction process, and left a lot of sensitive information exposed.

I personally use a photo editor called Zoner Photo Studio, but the same technique can be used in Photoshop.

First, lets play with the image levels a little bit...

Move some sliders around, and text begins to magically appear!

Now let's adjust the contrast and brightness a little.

After performing the manipulations above, I doubled the size of the image for easier examination.

Click to View Full Size

You can pretty clearly make out some of the details, including mailing address and phone numbers.

Of course this information is already available online anyways, so I'm not sure why it was redacted.  However, this could be a very interesting technique to use against Freedom of Information Act documents with redacted sections.

Once again, related reading: A Primer On Electronic Document Security.
Maybe someone will pay attention this time.