This paper investigates the theoretical and practical aspects of cryptographic hash functions in contemporary information security systems. The study analyzes their security properties, operational structures, and applications in ensuring integrity verification, authentication, and resistance to unauthorized modifications. Major hash algorithms, including MD5, SHA-1, SHA-2, SHA-3, and BLAKE2, are examined with respect to their design principles, strengths, and limitations. Additionally, current challenges involving collision attacks and quantum computing threats are discussed. The findings indicate that cryptographic hash functions remain essential components of modern cybersecurity frameworks and digital communication systems.