Security by Design: A Comprehensive Guide with Software Engineering Examples


Security by Design (SbD) is a robust methodology that emphasizes the integration of security as a fundamental objective throughout all phases of product creation and deployment. Recognizing historical shortcomings in hardware deployments and IoT design, where security considerations were often an afterthought, SbD aims to eliminate vulnerabilities introduced during the late stages of design and prototyping. This is particularly relevant in the fast-paced landscape where prioritizing speed to market can compromise security.

Principles of Security by Design

Security by design principles provide a foundation for developing secure software systems. In software engineering, these principles translate into actionable guidelines:

  1. Minimize Attack Surface Area: In software engineering, this involves reducing the potential entry points to a system, such as limiting external interfaces and inputs, thereby minimizing vulnerabilities.
  2. Establish Secure Defaults: Software engineers can set up secure default configurations for applications, ensuring that the system starts with a secure baseline.
  3. Apply the Principle of Least Privilege (PoLP): In the realm of software development, PoLP is implemented by granting users or processes only the minimum privileges required for their intended tasks.
  4. Apply the Principle of Defense in Depth (DiD): In software architecture, the DiD approach involves implementing multiple layers of security controls to mitigate the impact of a potential failure.
  5. Fail Securely: Software applications can be designed to handle failures gracefully, preventing unauthorized access or data breaches even in the event of a system failure.
  6. Don’t Trust Services: In software engineering, this principle advises against blind trust in external services, advocating for verification and validation of inputs and outputs.
  7. Separate Duties: This involves designing systems with clear role-based access controls, limiting the scope of user privileges based on their responsibilities.
  8. Avoid Security by Obscurity: Software engineers should rely on proven security mechanisms rather than obscure methods for safeguarding information.
  9. Keep Security Simple: Complex systems often introduce more potential vulnerabilities. Software engineers are encouraged to adopt simplicity in their designs, making security more manageable.
  10. Fix Security Issues Correctly: When vulnerabilities are identified, software engineers should address them at their root, ensuring that patches and fixes are effective and not merely superficial.
  11. Establish the Context Before Designing a System: In software engineering, understanding the context includes a thorough analysis of the application’s purpose, potential threats, and the security requirements specific to its environment.
  12. Make Compromise Difficult, Disruption Difficult, and Compromise Detection Easier: Software engineers can implement measures that make it challenging for attackers to compromise the system, disrupt operations, and facilitate the detection of compromise.
  13. Reduce the Impact of Compromise: Designing systems with measures to minimize the impact of a security breach is crucial. This can involve encryption, access controls, and robust incident response plans.

Case Study: Kiktronik Limited’s Secured by Design Environment for a UK Fintech

Kiktronik Limited, a leading software development firm, implemented a robust Security by Design approach for a prominent UK-based fintech company. The project involved:

  • Minimizing Attack Surface Area: The development team reduced potential entry points by implementing strict API controls and input validation mechanisms.
  • Defense in Depth (DiD): Multiple security layers, including firewalls, intrusion detection systems, and encryption protocols, were integrated to ensure a comprehensive defense strategy.
  • Establishing Secure Defaults: The software was configured with secure default settings, minimizing the need for users to make manual adjustments to enhance security.
  • Principle of Least Privilege (PoLP): Role-based access controls were implemented, ensuring that employees and systems only had the minimum level of access required for their tasks.
  • Continuous Awareness Among Developers: Regular training sessions were conducted to educate developers on emerging threats and best practices, fostering a security-conscious development culture.
  • Security Risk Analysis: A thorough risk analysis was performed, identifying potential threats, vulnerabilities, and their potential impact. Countermeasures were then implemented to mitigate these risks.
  • Trusted Digital Device IDs and Credentials: The system incorporated a foundation of secure device IDs and credentials, stored securely during manufacturing to prevent cloning, tampering, theft, or misuse.
  • Tamper-Resistant Secure Element: For enhanced security in sensitive areas such as financial transactions, IDs and credentials were stored in tamper-resistant Secure Elements, ensuring protection against physical and digital access.


Security by Design is a proactive and integral approach to software development that prioritizes security from the project’s inception. By adhering to these principles and leveraging software engineering best practices, organizations can minimize software-based risks and capitalize on the benefits of open source technologies[^10^]. The case study of Kiktronik Limited’s success in architecting a secured environment for a UK fintech exemplifies the practical application of Security by Design in real-world scenarios.

more insights