Column: Factors Affecting Data Decay

• Main Authors: Kevin Fairbanks, Simson Garfinkel
• Format: Article
• Language: English
• Published: Association of Digital Forensics, Security and Law 2012-06-01
• Series: Journal of Digital Forensics, Security and Law
• Online Access: http://ojs.jdfsl.org/index.php/jdfsl/article/view/123

<p>In nuclear physics, the phrase decay rate is used to denote the rate that atoms and other particles spontaneously decompose. Uranium-235 famously decays into a variety of daughter isotopes including Thorium and Neptunium, which themselves decay to others. Decay rates are widely observed and wildly different depending on many factors, both internal and external. U-235 has a half-life of 703,800,000 years, for example, while free neutrons have a half-life of 611 seconds and neutrons in an atomic nucleus are stable.<br />We posit that data in computer systems also experiences some kind of statistical decay process and thus also has a discernible decay rate. Like atomic decay, data decay fluctuates wildly. But unlike atomic decay, data decay rates are the result of so many different interplaying processes that we currently do not understand them well enough to come up with quantifiable numbers. Nevertheless, we believe that it is useful to discuss some of the factors that impact the data decay rate, for these factors frequently determine whether useful data about a subject can be recovered by forensic investigation.</p><p>(see PDF for full column)</p>