Launched in 2009, Bitcoin is one of the oldest digital currencies in use. Because transactions occur without the help of any third party, Bitcoin appears to preserve a high degree of anonymity. However, several studies have described the deanonymization of bitcoin addresses. Meiklejohn et al. [1] combined addresses managed by the same user to demonstrate the extraction of specific transaction patterns for individual users. Dupont et al. [2] succeeded in revealing a target user's time zone by analyzing the time distribution of transactions. The accuracy of their proposed scheme was only moderate, with an average identification ratio of 72%. The main reason for errors was that different users may have similar lifestyle patterns. Moreover, it is not clear how much anonymity depends on the frequency of transactions and the output address sets used.