The concept of authentication has been around for a long time in many forms. For example ‘due diligence’ in commerce has traditionally been formalised to determine whether the data presented in commercial propositions are accurate and comprehensive. With the emergence of e-commerce the concept of authentication has encompassed new realities that are a feature of the relatively narrow avenues for information and potentially high risks inherent in an online environment. The problem of authentication in the online world goes to the heart of trust and therefore confidence-building for ecommerce and all of the benefits that this entails. This paper seeks to provide an understanding about the different ways of assuring authentication. These authentication rules and tools – including for example Public Key Infrastructure (PKI) - are sometimes meant to set a legal and technological framework for trustworthy electronic transactions, promoting e-procurement, e-commerce, ebusiness and e-government.