Cryptocurrencies are digital currencies that use a combination of cryptography and a public-private key system to guarantee the security of their assets. These currencies rely on cryptography and not trust to back their value. 

Cryptocurrencies have gained a lot of popularity and are now widely accepted as a payment method in many online stores. The HEX extension for Hedera can serve as a hbar (native cryptocurrency of Hedera) paywall for content providers. In other words, users of HEX can pay to view content that Hedera makes available to them in the form of hbar tokens.

HEX was created as a result of an effort to solve many of the problems associated with cryptocurrencies.