This review paper explores the fundamental relationship between blockchain technology and cryptography, highlighting how cryptographic methods are essential for the security, integrity, and functionality of blockchain systems. Blockchain, a decentralized and distributed ledger technology, relies on cryptography to ensure tamper-proof records of transactions. This paper delves into the core cryptographic pillars of blockchain, including hashing algorithms, asymmetric cryptography (public and private keys), and digital signatures, explaining their roles in maintaining the blockchain's immutability, transparency, and security against double-spending and data manipulation. The paper also discusses real- world applications of blockchain in supply chain management and healthcare, illustrating the practical significance of its cryptographic underpinnings. Furthermore, it critically analyzes the strengths and limitations of relying on cryptography in blockchain, including challenges such as key management and thepotential threat of quantum computing.