Blockchain technology heavily relies on crypto- graphic hashing for security, integrity, and immutability. However, with the rise of quantum computing, traditional cryptographic algorithms such as RSA and Elliptic Curve Cryptography (ECC) face significant threats. This has led to increasing interest in hash- based signatures (HBS), which provide post-quantum security and robustness against cryptanalytic attacks. This paper explores the fundamentals of HBS, its advantages, challenges, potential use cases in blockchain, and future research directions to optimize its adoption