You can use bitcoin. But you can't hide from the taxman.

At least, that's the hope of the Internal Revenue Service, which has purchased specialist software to track those using bitcoin, according to a contract obtained by The Daily Beast.

The document highlights how law enforcement isn't only concerned with criminals accumulating bitcoin from selling drugs or hacking targets, but also those who use the currency to hide wealth or avoid paying taxes.

The IRS has claimed that only 802 people declared bitcoin losses or profits in 2015; clearly fewer than the actual number of people trading the cryptocurrency—especially as more investors dip into the world of cryptocurrencies, and the value of bitcoin punches past the $4,000 mark. Maybe lots of bitcoin traders didn't realize the government expects to collect tax on their digital earnings, or perhaps some thought they'd be able to get away with stockpiling bitcoin thanks to the perception that the cryptocurrency is largely anonymous.