Worked on the Zampfi/public-workflow-sdk repository to deliver secure payload encryption for the LargePayloadCodec, focusing on enhancing data security for client applications. Implemented Fernet-based encryption for smaller payloads using Python, introducing a new cryptography dependency and a validation mechanism to ensure correct encryption key formats. The approach allowed optional key-based encryption, enabling end-to-end payload protection when an encryption key is provided, while maintaining backward compatibility. Updated the SDK version to reflect these security improvements and ensure compatibility with dependent projects. The work demonstrated backend development expertise with a strong emphasis on cryptography and data security best practices throughout the process.