抄録
A key issue in secret voting and many other kinds of private communications is ensuring the anonymity of individuals. Researchers in Information Studies have been aiming to establish metrics of anonymity to enhance the protection of privacy in information and communication systems. Many related papers, however, focus on so-called connection anonymity. Little research can be found for metrics of voting privacy, except for the entropy-based approach of Endo et al. (2007, 2008). This study illustrates and evaluates an unknown anonymity measure presented by Iwai (2003) in the field of Japanese mathematical sociology. The metric utilizes a combinatorial approach and has some advantageous aspects over the approach of Endo et al. (2007, 2008) as a metric that measures the degree of preventing the identification of particular voters. Although, in general, Edman et al. (2007) is recognized as the first study that demonstrated a combinatorial approach to defining an anonymity measure, the main idea is shared by the earlier research of Iwai (2003). Even now, the mathematical representation forms in the older research seem to be more suitable for measuring anonymity in voting contexts.
