Executive Summary
A major UK Government Client undergoing a critical digital transformation required a secure and scalable digital infrastructure capable of handling OFFICIAL-SENSITIVE classified data and delivering next-generation public services. The agency was transitioning away from a legacy IT supplier and needed to modernise its technology stack while meeting the highest standards of cyber resilience. With increased scrutiny from national security bodies (GCHQ, NCSC) and a mandate to de-risk digital service delivery, the organisation engaged A&A Digital Tech to conduct a comprehensive multi-layered architecture and compliance review. This initiative formed a foundational component of the agency’s broader cloud-first and zero-trust security strategy, with outcomes expected to inform patterns across wider government adoption.
The Challenge
The agency faced a series of acute challenges:
🔒 Legacy systems lacked agility, modern security automation, and scalability.
🚫 Previous AWS deployment attempts failed due to non-compliance with OFFICIAL-SENSITIVE controls.
⚠️ Elevated threat levels from Foreign Intelligence Services (FIS) posed persistent risk.
📉 No reference architecture or best-practice patterns for secure cloud hosting.
👥 Complex stakeholder landscape, including various UK Government Departments, NCSC, and GCHQ, required alignment and assurance.
Our Approach
Methodologies & Review Framework:
🧭 Ran architecture review workshops across UK Government Departments, GCHQ, and NCSC.
🧱 Embedded structured assurance aligned to GDS Technology Code of Practice and NCSC Cloud Security Principles.
🛡️ Introduced risk-based architecture checkpoints at key delivery stages.
Industry-Standard Review Principles Applied:
To ensure a robust and audit-ready assessment, A&A Digital Tech integrated the following recognised frameworks:
📘 NIST Cybersecurity Framework (CSF): Mapped risks across five key functions.
🔍 OWASP Serverless Top 10: Assessed APIs and functions for common cloud-native threats.
📑 ISO/IEC 27001: Mapped controls to Annex A for security audit readiness.
🔐 DevSecOps & Secure SDLC: Embedded CI/CD security gates including SAST, CVE scans, and signed artifacts.
🔗 Zero Trust (NIST SP 800-207): Assessed identity enforcement and least privilege access patterns.
📏 AWS Well-Architected + CIS Benchmarks: Hardened deployments and conducted WAR reviews across three AWS pillars.
Tools & Interventions:
🧩 Reviewed AWS IAM, KMS, Lambda, API Gateway, S3, and VPC configurations.
🔒 Enforced end-to-end encryption using TLS and customer-managed KMS keys.
📡 Validated security observability using GuardDuty, Security Hub, StreamAlert, and CloudWatch.
🛠️ Reviewed privileged access controls including break-glass workflows and multi-party approvals.
📂 Delivered detailed threat models, test cases, and reusable design templates.
Assurance Governance:
📝 Produced artefacts aligned with UK Government, Cyber Assurance Board, and NCSC requirements.
🔄 Created reusable review accelerators and playbooks to scale architecture assurance across portfolios.
Outcomes Achieved
✅ NSC-approved architecture for OFFICIAL-SENSITIVE data hosted on AWS serverless platform.
📈 Compliance gates passed with no remediation across TDA, CyIAB, and Delivery Board.
🚀 Reference patterns reused across multiple transformation programmes.
💡 Security innovation embedded zero trust, privilege management and monitoring implemented from day one.
💰 Operational and assurance cost savings through automation, reduced audit overhead, and reuse.
Key Learnings and Takeaways
🧠 Embedding multi-layered reviews into agile cycles ensures assurance does not delay delivery.
📚 Leveraging global standards (NIST, ISO, OWASP) accelerates stakeholder buy-in.
📦 Creating modular design and risk artefacts improves reusability across programmes.
📊 Industry-aligned reference architectures support fast-track approval and onboarding for future services.
