Cybercrime has increased in severity and frequency in the recent years and because of this, it has become a major concern for companies, universities and organizations. The anonymity offered by the Internet has made the task of tracing criminal identity difficult. One study field that has contributed in tracing criminals is authorship analysis on e-mails, messages and programs. This paper contains a study on source code authorship analysis. The aim of the research efforts in this area is to identify the author of a particular piece of code by examining its programming style characteristics. Borrowing extensively from the existing fields of linguistics and software metrics, this field attempts to investigate various aspects of computer program authorship. Source code authorship analysis could be implemented in cases of cyber attacks, plagiarism and computer fraud. In this paper we present the set of tools and techniques used to achieve the goal of authorship identification, a review of the research efforts in the area and a new taxonomy on source code authorship analysis.