Information technology systems are attacked by offenders using digital devices and networks to facilitate their crimes and hide their identities, creating new challenges for digital investigators. Malicious programs that exploit vulnerabilities also serve as threats to digital investigators. Since digital devices such as computers and networks are used by organisations and digital investigators, malicious programs and risky practices that may contaminate the integrity of digital evidence can lead to loss of evidence. For some reasons, digital investigators face a major challenge in preserving the integrity of digital evidence. Not only is there no definitive comprehensive model of digital forensic investigation for ensuring the reliability of digital evidence, but there has to date been no intensive research into methods of doing so.
To address the issue of preserving the integrity of digital evidence, this research improves upon other digital forensic investigation model by creating a Comprehensive Digital Forensic Investigation Model (CDFIM), a model that results in an improvement in the investigation process, as well as security mechanism and guidelines during investigation. The improvement is also effected by implementing Proxy Mobile Internet Protocol version 6 (PMIPv6) with improved buffering based on Open Air Interface PIMIPv6 (OAI PMIPv6) implementation to provide reliable services during handover in Mobile Node (MN) and improve performance measures to minimize loss of data which this research identified as a factor affecting the integrity of digital evidence. The advantage of this is to present that the integrity of digital evidence can be preserved if loss of data is prevented.
This research supports the integration of security mechanism and intelligent software in digital forensic investigation which assist in preserving the integrity of digital evidence by conducting experiments which carried out two different attack experiment to test CDFIM. It found that when CDFIM used security mechanism and guidelines with the investigation process, it was able to identify the attack and also ensured that the integrity of the digital evidence was preserved. It was also found that the security mechanism and guidelines incorporated in the digital investigative process are useless when the security guidelines are ignored by digital investigators, thus posing a threat to the integrity of digital evidence
