Qualitative assessment of authentication measures

Internet is now a vital tool for every field today. Every sphere of individuals, groups, business, trade, government is regulated by safety measures for their activities in the online world. E-cash and identity documents needs varied authorization and certification to be able to access with certain degree of validity. However, privacy and security of any entity in the digital world is inevitably threatened in one or the other way. In order, authentication is underway for verifying the individual's entity who wants to access the resources of a system. However, there is a trade-off between the usability and the security of such approaches. This paper reviews the currently used authentication techniques, methods, mechanisms and protocols for the prevailing state of-the-art in the field. Finding a little or no evident interest on efficiency aspect by researchers, it appeared pertinent to take a look from efficiency perspective in view of ever increasing usage of authentication. In turn, some cues on efficiency aspect are derived, which can result in development of effective as well as efficient authentication measures.