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The traditional approach to a digital investigation when a computer system is encountered in a running state is to remove the power, image the machine using a write blocker and then analyse the acquired image. This has the advantage of preserving the contents of the computer’s hard disk at that point in time. However, the disadvantage of this approach is that the preservation of the disk is at the expense of volatile data such as that stored in memory, which does not remain once the power is disconnected. There are an increasing number of situations where this traditional approach of ‘pulling the plug’ is not ideal since volatile data is relevant to the investigation; one of these situations is when the machine under investigation is using encryption. If encrypted data is encountered on a live machine, a live investigation can be performed to preserve this evidence in a form that can be later analysed. However, there are a number of difficulties with using evidence obtained from live investigations that may cause the reliability of such evidence to be questioned. This research investigates whether digital evidence obtained from live investigations involving encryption can be considered to be reliable. To determine this, a means of assessing reliability is established, which involves evaluating digital evidence against a set of criteria; evidence should be authentic, accurate and complete. This research considers how traditional digital investigations satisfy these requirements and then determines the extent to which evidence from live investigations involving encryption can satisfy the same criteria. This research concludes that it is possible for live digital evidence to be considered to be reliable, but that reliability of digital evidence ultimately depends on the specific investigation and the importance of the decision being made. However, the research provides structured criteria that allow the reliability of digital evidence to be assessed, demonstrates the use of these criteria in the context of live digital investigations involving encryption, and shows the extent to which each can currently be met.

Carbohydrates are one of the most structurally and functionally diverse classes of naturally occurring compounds and it is well established that they play an essential role in a vast array of biological processes. The synthesis of stereochemically defined oligosaccharides by a series of glycosylation processes, involving the reaction between a glycosyl donor and acceptor, is of paramount importance in synthetic carbohydrate chemistry and glycobiology. However, despite the importance of glycosylation chemistry and the development of sophisticated methodologies, there remains no general and stereoselective strategy that has been universally adopted for the syntheses of oligosaccharides. In this thesis we present the synthesis and function of a novel family of glycosyl donors, in which fluorinated pyridine systems are utilised as the leaving group. In systems of this type it proved possible to 'tune' the glycosylation capability of the donor via variation of the substituents present on the pyridine ring and the type of Lewis acid activator used. The formation of a glycosidic bond with control of the stereochemistry at the anomeric centre is usually difficult. Interestingly glycosyl donor systems of this type provide a high degree of stereoselectivity, providing diastereomeric excesses in the region of 80 to 98%. It has been determined that polyfluoro-pyridyl glycosyl donors do not react via the established Sn1 glycosylation process but via an unique Sn2 process which gives rise to the high degree of stereoselectivity observed.