  In the past year, a new spamming scheme has emerged: sexual extortion
messages requiring payments in the cryptocurrency Bitcoin, also known as
sextortion. This scheme represents a first integration of the use of
cryptocurrencies by members of the spamming industry. Using a dataset of
4,340,736 sextortion spams, this research aims at understanding such new
amalgamation by uncovering spammers' operations. To do so, a simple, yet
effective method for projecting Bitcoin addresses mentioned in sextortion spams
onto transaction graph abstractions is computed over the entire Bitcoin
blockchain. This allows us to track and investigate monetary flows between
involved actors and gain insights into the financial structure of sextortion
campaigns. We find that sextortion spammers are somewhat sophisticated,
following pricing strategies and benefiting from cost reductions as their
operations cut the upper-tail of the spamming supply chain. We discover that
one single entity is likely controlling the financial backbone of the majority
of the sextortion campaigns and that the 11-month operation studied yielded a
lower-bound revenue between \$1,300,620 and \$1,352,266. We conclude that
sextortion spamming is a lucrative business and spammers will likely continue
to send bulk emails that try to extort money through cryptocurrencies.
