Design and implementation of secure web applications using ASP.NET Core and NET framework

The rapid growth of web-based applications has intensified the need for secure development methodologies. ASP.NET Core and the .NET Framework provide robust architectural models and built-in security mechanisms for developing enterprise-grade web applications. However, improper implementation can expose systems to severe vulnerabilities such as injection attacks, broken authentication, insecure deserialization, and cross-site scripting. This research explores the design principles, architectural patterns, authentication mechanisms, authorization strategies, cryptographic implementations, and secure deployment practices for ASP.NET Core and .NET Framework applications. By synthesizing existing literature (pre-2023), OWASP guidelines, and practical implementation models, this study proposes a structured security-oriented development framework. Visual models including architectural diagrams, sequence diagrams, mind maps, and comparative tables are used to enhance conceptual clarity. The research contributes a consolidated approach toward building secure, scalable, and maintainable ASP.NET-based web systems.