What Is Cryptocurrency? Here’s What You Should Know Cryptocurrencies let you buy goods and services, or trade them for profit. Here's more about what cryptocurrency is, how to buy it and how to protect yourself. Cryptocurrencies let you buy goods and services, or trade them for profit. Many companies have issued their own currencies, often called tokens, and these can be traded specifically for the good or service that the company provides. Cryptocurrencies work using a technology called blockchain. Blockchain is a decentralized technology spread across many computers that manages and records transactions. Part of the appeal of this technology is its security. More than 10,000 different cryptocurrencies are traded publicly, according to CoinMarketCap, a market research website. And cryptocurrencies continue to proliferate, raising money through initial coin offerings, or ICOs. The total value of all cryptocurrencies on Aug. 18, 2021, was more than $1.9 trillion — down from April hi...