$ENA Cryptocurrencies are decentralized digital assets that use cryptography to secure transactions. Bitcoin, the first, was created in 2009 by Satoshi Nakamoto. Ethereum introduced smart contracts, expanding its utility. Blockchain is the underlying technology, ensuring transparency and immutability. Altcoins like Litecoin and Ripple offer alternatives with different speeds and uses. Stablecoins, such as USDT, maintain a stable value linked to reserves. Exchanges facilitate their buying and selling, but with volatility and risks. NFTs tokenize unique assets, revolutionizing digital art. DeFi allows finance without intermediaries. Regulations vary globally, impacting their adoption. Promising future, but with challenges of scalability and security.