How to securely dispose of your paper documents

Identity fraud is a major issue facing Americans today. While new methods of securing sensitive personal information are continuously developed, thieves and fraudsters are also racing to bypass or surmount them. This battle is ongoing with digital data, and beyond following security best practices (strong, unique passwords for online accounts) and excersizing good sense, there isn't much you can do.

With offline data on the other hand, you retain a good amount of control over the amount of data you leak. However, note that not all disposal or redaction methods are secure. In this article we'll discuss a few commonly used methods for disposing of documents and make a recommendation on the approach you should use.

Shred everything

shredded paper

The sub-heading says it all. If you have access to a shredding machine, whether at home or in your office, you should make copious use of it. Shredding is probably the simplest way to make the life of dumpster-diving, trash-stealing identity thieves difficult.

Beware, however, that not all shredders are equal.

Strip-cut shredders will cut paper into parallel stripes of equal length, and are the least secure shredder type. Since the original document may be relatively easily re-assembled with access to the shredding, we do not recommend that you purchase one.

strip cut

Even a partial recovery of paper shredded by a strip-cut machine could potentially contain a lot of meaningful information.

Cross/confetti-cut shredders are probably the most widely available and heavily utilized shredders among families and small businesses.
cross cut Not all cross-cut shredders are equal. Beyond the type of cut, shredders are also distinguished by their security level, which indicates the maximum size of paper output by the shredder. The security level might vary widely among cross-cut shredders, so pay careful attention to the specifications of the shredder you are interested in purchasing before you buy it. The greater the security level, the finer the shredded output, which enhances security.

However, that isn't the final word on cross-cut shredders. A casual search for research papers on reconstructing documents from a pile of cross-cut documents turns up several hits. There are human-aided and unsupervised approaches to reconstruction that successfully extract meaningful information from cross-cut strips. If you're targetted by a sufficiently sophisticated or determined fraudster, they may be able to leverage these techniques against you with your shredded documents.

One way to mitigate this issue is to combine batches of shredded paper from different documents before disposing them. In reducing the amount of consistent information available to the reconstruction program (by overwhelming it with information for unrelated documents), you increase the program's running time and possibly prevent it from producing a reconstruction that contains meaningful, extractable information.

All of that said, for your typical home or office use, these devices provide adequate security and are typically available for a reasonble price ($50-$250).

particle/micro-cut shredders There are higher-end-still shredders that are suitable for more sensitive information (but probably not the most sensitive information), like collections of health or financial information, or information collected by governmental organizations (perhaps excluding things like social security number). These shredders produce an even finer output than cross-cut, and the output's geometry is much more irregular.

The irregular geometry and smaller size should make all but the most sophisticated (and likely classified) programs inadequate to the task of reconstituting the original documents.

Good micro-cut shredders will tend to cost more than their cross-cut competitors, and may have other limitations like slower throughput. They may be worthwhile for certain workloads however, so you should take a moment to reflect on the typical documents you will shred, and consider whether the additional expense is worth the added peace of mind it buys.

What if you can't afford a shredder or do not process enough documents to warrant one?

In that case you might be tempted to simply rip your documents with your bare hands (or aided by scissors).

You must fight this urge.

No matter how good a job you think you've done, hand-ripped documents tend to be trivial to reconstruct. Combining relatively large (compared to the output of a shredder) strips of paper, each with relatively unique edges, is a trivial task for a computer to solve, and may even be straightforward for a human being with enough time devoted to the task.

So don't do this.

It might also be tempting to use a thick black marker to redact sensitive or personal information from your documents before you dispose of them. This procedure is not a panacea either, as this article clearly explains.

Depending on the document, the type of marker used, the sensitivity of information contained therein, and your sensitivity to its recovery, you might be okay settling for this solution.

But I recommend holding off on disposing of your documents and saving money for a proper cross-cut or micro-cut paper shredder instead. In the long run, you'll be much better off.


How do you deal with securing and disposing of your sensitive paper documents? Let us know in the comments below, or via twitter, facebook, google+, or even email!