Hypothesis-based investigation of digital timestamps

Abstract

Timestamps stored on digital media play an important role in digital investigations. However, the evidentiary value of timestamps is questionable because timestamps can be manipulated or they could refer to a clock that is erroneous or improperly adjusted. This paper presents a formalism for defining clock hypotheses based on historical adjustments to clocks, and for testing the consistency of the hypotheses with respect to stored timestamps. Two consistency tests are proposed for justifying clock hypotheses without having to rely on timestamps from external sources. © 2008 International Federation for Information Processing.