A framework for authorship identification of online messages: Writing-style features and classification techniques

With the rapid proliferation of Internet technologies and applications, misuse of online messages for inappropriate or illegal purposes has become a major concern for society. The anonymous nature of online-message distribution makes identity tracing a critical problem. We developed a framework for authorship identification of online messages to address the identity-tracing problem. In this framework, four types of writing-style features (lexical, syntactic, structural, and content-specific features) are extracted and inductive learning algorithms are used to build feature-based classification models to identify authorship of online messages. To examine this framework, we conducted experiments on English and Chinese online-newsgroup messages. We compared the discriminating power of the four types of features and of three classification techniques: decision trees, back-propagation neural networks, and support vector machines. The experimental results showed that the proposed approach was able to identify authors of online messages with satisfactory accuracy of 70 to 95%. All four types of message features contributed to discriminating authors of online messages. Support vector machines outperformed the other two classification techniques in our experiments. The high performance we achieved for both the English and Chinese datasets showed the potential of this approach in a multiple-language context. Introduction The rapid development and proliferation of Internet technologies and applications have created a new way to share information across time and space. A wide range of activities have evolved over the Internet, ranging from simple information exchange and resource sharing to virtual communications and e-commerce activities. In particular, online messages are being extensively used to distribute information over Web-based channels such as e-mail, Web sites, Internet newsgroups, and Internet chat rooms. Unfortunately, online messages also can be misused for the distribution of unsolicited or inappropriate information such as junk mail (commonly referred to " spamming ") and offensive/threatening messages. Moreover, criminals have been using online messages to distribute illegal materials, including pirated software, child pornography materials, stolen properties, and so on. In addition, criminal or terrorist organizations also use online messages as one of their major communication channels. These activities have spawned the concept of " cybercrime. " Cybercrime was defined by Thomas and Loader (2000) as illegal computer-mediated activities which can be conducted through global electronic networks. A common characteristic of online messages is anonymity. People usually do not need to provide their real identity information such as name, age, gender, and address. In many misuse or crime cases of online messages, the sender will …