The rise of cryptocurrencies has led to new legislation from Spanish tax authorities, who are trying to stay ahead of the technological curve.
Their main concern is that new payment methods could be used for money laundering and funding terrorism.
A paper published on Tuesday also highlighted the growth of organised crime through the 'deep web', where the anonymous cryptocurrency Bitcoin is used to purchase illegal items.
To combat this threat, the authority has said that it will investigate the uses of new technologies such as cryptocurrencies and Blockchain, by analysing information from a range of sources.
The tax authority is considering implementing forms of control over new payment methods, such as online wallets.
It has also proposed new taxes on revenue generated by sharing economy businesses.
A new law set to come into force in July will oblige companies such as AirBnB to disclose both the owners and the tenants of properties listed on their websites.
The authority recognises that it needs to expand its online operations given the growth of digital payments.