Developing Blockchain-Based Budgeting Applications

Assume the role of a blockchain development consultant to design a secure and transparent budgeting application leveraging blockchain technology. Outline a step-by-step plan including key features such as transaction recording, immutable ledgers, privacy considerations, and smart contracts. Detail the technology stack required, data security measures, and methods for user authentication. Additionally, provide strategies for integrating this application into existing financial systems while ensuring scalability and compliance with financial regulations. Aim for a user-friendly design and seamless user experience. Conclude with potential challenges and solutions.