Evaluating A Selection of Tools for Extraction of Forensic Data: Disk ...

oth original and duplicate copy of mirror images. Both hash values must be the same
to verify that both images are identical. A court case United States v. Liebert (3rd Cir.
1975) argued the exhibit presented as evidence against him should not be admissible
because of the duplicability and modifiability nature of digital evidence. The argument
presented in this case showed that the evidence obtained from an investigation must be
properly authenticated before it can be admissible in court.
In conclusion, admissibility of digital forensic evidence must meet three
requirements: first the evidence must be relevant to the case investigated, second it
must be obtained with scientific methods, and third it must be confirmed by proper
validation. The criterion is reliability when the evidence is regarded as admissible
(Ryan & Shpantzer, 2002). When developing and using digital forensic tools that
might be producing digital evidence that are introduced to court, these requirements
must be considered.
2.2.3 Open Source and Proprietary Digital Forensic Tools
The fundamental principles of Daubert guidelines and other requirements of admitting
evidence in the court are covered in section 2.2.2. Digital forensic software is a tool
that assists digital investigators to acquire or locate potential digital evidence. The
validity of digital forensic software must be fully assessed before the evidence is
treated as admissible. Carrier (2002) and Dan et al. (2007) raised an argument of
whether digital forensics using Open source tools would be better. Goel (1985)
defined that software reliability is satisfied if software faults do not cause a failure
during a specified exposure period in a specified environment. Understandably,
unreliable digital forensic software will lead to untrustworthy results and may
jeopardise the whole forensics investigation.
It is important to distinguish between Open source and Proprietary Software.
The central defining point of Open source and Proprietary software is the availability
of the source code. Open source software allows open access to the source code
whereas Proprietary software makes their source code unavailable to the public. Some
prominent examples of Open source software (OSS) include Ubuntu, Apache web
server, Firefox web browser, and MySQL database. The counterpart proprietary
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