The importance of cryptographic hash functions in data security lies in their ability to ensure data integrity and authenticity. These functions generate unique, fixed-size hash values from input data, making it easy to detect any alterations or tampering. In security protocols, hash functions are used in digital signatures and message authentication codes, helping to confirm the identity of the sender and the integrity of the message. By safeguarding data against unauthorized modifications, hash functions play a vital role in protecting sensitive information and maintaining trust in digital communications.