Cryptocurrency or digital currency is a digital asset built on blockchain technology, a decentralized ledger that records every transaction transparently and securely. Without a central authority like a bank, crypto enables direct value exchange between users through peer-to-peer principles. Bitcoin pioneered this movement as digital gold, followed by Ethereum introducing smart contracts. Now, its ecosystem has expanded to decentralized finance (DeFi), unique tokens (NFT), and Web3. Although it offers high potential returns and global efficiency, the crypto market is known for its high volatility. Asset security depends on users' private keys, embodying the concept of full financial sovereignty in the digital age of the future.