Cryptocurrencies are encrypted digital currencies used as a means of exchange online without the need for a central intermediary like banks. They rely on blockchain technology, which is a distributed digital ledger that ensures transparency and security. The most famous of these are Bitcoin and Ethereum. These currencies provide privacy and speed in transactions, but they are affected by high price volatility. They are used in investment, payment, and cross-border money transfers. Despite their benefits, they face challenges such as fraud, money laundering, and legal regulation. Their global adoption is increasing, and some countries are seeking to regulate their use, while central banks are developing official digital versions of their currencies. Cryptocurrencies represent a financial revolution that changes the concepts of traditional economics.