With the rapid development of information technology, data security issues have received increasing attention. Data encryption and decryption technology, as a key means of ensuring data security, plays an important role in multiple fields such as communication security, data storage, and data recovery. This article explores the fundamental principles and interrelationships of data encryption and decryption, examines the strengths, weaknesses, and applicability of symmetric, asymmetric, and hybrid encryption algorithms, and introduces key application scenarios for data encryption and decryption technology. It examines the challenges and corresponding countermeasures related to encryption algorithm security, key management, and encryption-decryption performance. Finally, it analyzes the development trends and future prospects of data encryption and decryption technology. This article provides a systematic understanding of data encryption and decryption techniques, which has good reference value for software designers.