  Mixer services purportedly remove all connections between the input
(deposited) Bitcoins and the output (withdrawn) mixed Bitcoins, seemingly
rendering taint analysis tracking ineffectual. In this paper, we introduce and
explore a novel tracking strategy, called \emph{Address Taint Analysis}, that
adapts from existing transaction-based taint analysis techniques for tracking
Bitcoins that have passed through a mixer service. We also investigate the
potential of combining address taint analysis with address clustering and
backward tainting. We further introduce a set of filtering criteria that reduce
the number of false-positive results based on the characteristics of withdrawn
transactions and evaluate our solution with verifiable mixing transactions of
nine mixer services from previous reverse-engineering studies. Our finding
shows that it is possible to track the mixed Bitcoins from the deposited
Bitcoins using address taint analysis and the number of potential transaction
outputs can be significantly reduced with the filtering criteria.
