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An inexpensive method to shield wireless devices during hardware forensic investigation in a laboratory setting

Wireless devices have become prolific in society today. Unfortunately, this paradigm is increasingly useful by criminals during the execution of their illegal actions. A cellular telephone is used as the example in this paper. Our students are taught how to obtain vital information from the phone, for example, by downloading internal files (numbers-called lists, for example) onto an external computer.
 As the phone is transported to the laboratory, it will be handed-off from one cell site to another, as it would normally operate while roaming. As these hand-offs occur, files in the phone, as well as radio settings, adapt to the new cell sites. When the phone arrives at the laboratory, it has been altered. If in its powered-down state during confiscation at the crime scene, as soon as it is powered-on in the laboratory, it will associate, or connect, to the local cell site in that area, and again its contents will change.
 To be useful in the classroom, a low-cost method is needed to shield the phone from association with a cellular system. Shielding boxes are available commercially that provide the necessary shielding that preserves the pre-investigation state of the phone. However, these boxes, sometimes incorrectly referred to as, "Faraday shields (or cages)," are prohibitively expensive in the context of classroom use.
 It is very beneficial for the students in our forensics courses to be exposed to these issues, and provide them the opportunity to use such a shielding environment in hands-on exploratory laboratory experiences. A homemade unit, completely shielded, with appropriate power and data line filtering is discussed in detail. It can be constructed in any minimal shop with standard hand tools where almost all materials are obtained from a local home improvement center, with only a handful of special electrical components needed. The theory underlying its requirements is explained in terms understandable by non-engineering personnel. The shielding box will be shown to provide adequate shielding for cellular telephones from nearby cell sites.