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Security by Design Methodology

This ISA United Defensible Architecture methodology outlines a new process-oriented approach to developing enterprise security architecture. It draws from both well-known open frameworks as well as ISA United’s rich experience in architectural design and development. In this paper, we provide you with the various phases of the ISA United Defensible Architecture, and how they form the foundation for your next enterprise architecture.

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Introduction to the ISAU Defensible Architecture (IDA) Methodology

Our commitment to security architecture has resulted in ISA United supporting dedicated teams of security architects focused on advancing architectural security posture. We designed this teachable approach to deliver a security architecture foundation for organizations to institute a proper security architecture methodology to address business requirements and solve problems.

ISA United has developed this approach into a complete architectural methodology and process framework. With great pride, we’re excited to introduce this to a wider audience as the ISA United Defensible Architecture methodology. We know that organizations see value in a structured approach to security architecture, which is why ISA United developed the Defensible Architecture methodology.

This methodology allows any enterprise security team to develop a secure architecture using a formulated, accountable, and comprehensive process and to help security practitioners explain, develop, mature their security posture, and align with security best practices. Through our process, architects are able to accurately capture and record business requirements and convert these into tangible security solutions.

As a member, you will have full access to the Design process below 

You will be introduced to the methodology, its conception, and ease of use. You will look at each layer of the design process in more detail. Explore the purpose of each phase layer, and how it contributes to the overall outcome of the ISAU Defensible Architecture Design.

Security by Design Phased Approach


​1. Pre-Design Phase


2. Discovery Phase

3. Design Development Phase

  • Concept Design

  • Technical Design


4. Post-Design Phase

Become a member today to access the new design methodology and other great documentation.




ISAU Library is your platform for the latest in security architecture design and practice. This core collection covers all technical areas of security architecture. ISAU’s Library includes:

Foundational and Technical Standards



Manuals and Reports

and more.

ISAU continues to respond to practitioners’ needs for reliable professional tools.  We will continue to share updates on our standards transformation. 


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