This Week’s Thoughts: Hidden data

Many people send texts, spreadsheets, photos and videos—while not knowing that they contain much information that other people can discover with ease and that might be indiscreet. Who has collaborated on the text? How often has it been revised? What camera and aperture has been used to take the photo? Such info is hidden in files, it can be useful, but also indiscreet. We make these hidden data visible and show how to get rid of them in case of any doubts.

Invisible additional info

Whether Word, Excel or PowerPoint—the innocent icons don’t tell what is inside them. Normally it is documents like texts. And they contain much additional info. That can be comments, but also revision notes. However, there is surely information which is not suitable for the public.

Office icons

Awkward potential

In business it is truly important to be careful. When several collaborators work on a document, send it back and forth via e-mail and make corrections, such a document can contain inflammable matters. The problem: when you hide the comments and annotations, they are no longer visible at first sight. And that is exactly what is dangerous. Because, when you send such a document to a customer, for example via mail, resourceful users can make the data visible again anytime. And that’s what can get awkward.

Remove personal data

But private computer users should know, too, that their documents contain a massive amount of data, data that might not be suitable for everybody. That can be data like a counter how often a document was edited—and by whom it was edited last. People who save the texts, spreadsheets or presentations normally and distribute them, is likely to distribute their indiscreet data as well. But: you can change that. The latest Office version can remove all personal data.

Useful feature in Office 2007

Office 2007 has a really useful feature, called “Inspect document”. The feature checks whether there is any hidden information. If yes, these data can be removed from the document with a single click. Only after having done this, you should send the document to other people via e-mail. Older Office and Word versions cannot do this, sadly.

Free tool

However, Microsoft offers a free tool to remove hidden data in Office documents. “Office Add-in: Remove Hidden Data” is the name of this useful extension. Once installed, it can “clean” any document with a single click. Important thing, you should really take a closer look at this, especially when distributing documents, sending them via mail or publishing them on the Web.

Indiscreet photos

Photos can be really indiscreet as well. Not only concerning the motive, that is sure. When you take photos with your digital camera nowadays, you have to be aware that there is a massive amount of data hidden in the photos, data that we normally don’t see. For example, let’s take a photo that I just took of a nice espresso machine. Looks great—and nobody knows what I used to take the photo. Nobody? As if! The photo contains many hidden data. And you can make these data visible. And behold: The photo has been taken with an iPhone. Even the used aperture, time and date date hidden within the photo.

EXIF info detected in a photo

EXIF data

This information hidden in the photo are also known as EXIF data. They can be extraordinarily useful, for instance for hobby photographers, as they can find out easily what aperture and exposure time they used to take a photo. If colleagues extract these data from a photo, that could get uncomfortable. For example, when you are discovered to be skiving off work because your colleagues found a party photo being taken just while you were ill.

JPG & PNG Stripper

Generally, it is very easy to make these EXIF data visible, for example in Windows: Just select the photo and click on details in Windows Explorer, and info like creation time, aperture, exposure time, camera type and much more are shown. The Mac can show these data easily as well. If you want to remove your data from your photos, for example because you want to publish the photos on the Web, you can remove the additional data from the photos. Just use special programs like JPG stripper, and you’re done. The photos are retained. Only the additional data are removed from the photos. If you don’t want everybody to see the additional info, you should always do this. In any case, it is more discreet.

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