Naval Postgraduate School

An Analysis of the Applicability of Federal Law Regarding Hash-based Searches of Digital Media Naval Postgraduate School

The Fourth Amendment of the United States (U. S.) Constitution limits the ability of the government to search U. S. persons without cause or justification. The application of the Fourth Amendment to digital forensics search techniques is still evolving. This thesis summarizes current federal law and recent judicial rulings that can apply Fourth Amendment doctrine to current digital forensics techniques. It uses three hypothetical scenarios to show how current law could be applied to new techniques now under development: the use of sector hashes to find traces of digital contraband; the use of random sampling to rapidly triage large digital media; and the use of similarity functions to find documents that are similar but not identical to target documents.