This chapter introduces the Secure and Sustainable Software Engineering Framework for Blockchain Applications (S3EF-BC), designed to address the unique challenges of blockchain technology, such as scalability, energy efficiency, security, and privacy. The S3EF-BC framework emphasizes secure coding practices, energy-efficient operations, and reusability of blockchain components. The chapter discusses the Agile methods suitable for blockchain development in healthcare and explores strategies for managing cybersecurity attacks and privacy issues. The chapter concludes with a critical evaluation of the S3EF-HBCAs framework, which is tailored to healthcare applications, integrating secure requirements engineering, smart contract validation, and energy-efficient consensus mechanisms.