Block chain technology has gained significant attention across multiple domains such as finance, healthcare, education, and real estate. It serves as the foundational technology behind cryptocurrencies, enabling secure and decentralized digital transactions. Transactions are carried out using digital wallets on computing devices and are permanently recorded as blocks linked together in a distributed ledger known as the block chain. This paper presents a comprehensive study of block chain technology, its operational principles, consensus mechanisms, and real-world applications. It also explores the integration of artificial intelligence techniques to enhance security, scalability, and trust in block chain-based cryptocurrency systems.