Blockchain technology for cryptocurrency is a foundational research area that focuses on designing decentralized, secure, and transparent digital currency systems. Early research centered on Bitcoin, introducing concepts such as peer-to-peer networks, Proof of Work (PoW), and immutable ledgers. Subsequent studies explored alternative consensus mechanisms like Proof of Stake (PoS), Delegated Proof of Stake (DPoS), and hybrid models to improve scalability, energy efficiency, and transaction throughput. Research also addresses cryptographic techniques, wallet security, transaction privacy, smart contract integration, and regulatory compliance. Recent developments include decentralized finance (DeFi), cross-chain transactions, stablecoins, and privacy-preserving cryptocurrencies leveraging zero-knowledge proofs and homomorphic encryption. Applications span peer-to-peer payments, remittances, decentralized exchanges, and tokenized asset systems. Current studies emphasize scalability, security, decentralization trade-offs, regulatory adherence, and interoperability, establishing blockchain as the core enabler of secure, efficient, and trustless cryptocurrency ecosystems.