Cryptocurrencies are digital currencies based on blockchain technology, operating without a central bank. In marketing they appear from two sides: as a form of payment, and as an industry for which campaigns are run (exchanges, wallets, fintech). It is an area still being put in regulatory order (in the EU under the MiCA regulation, among others) and prone to swings in sentiment, which translates into caution from ad platforms towards the category. (Compare: Block Chain, Mobile Wallet)