Senior Security Engineer/Architect (Blockchain/Web3)

Madfish; United Kingdom; Remote; GBP 60,000 - 90,000; Full time

Job summary

A prominent blockchain company in the United Kingdom is seeking a Security Engineer/Architect with deep knowledge of security engineering and blockchain technologies. The ideal candidate will excel in a fast-paced environment, owning security across various projects, and must possess strong hands-on experience in DevSecOps and cloud platforms. Responsibilities include maintaining security controls, updates on vulnerabilities, and acting as a technical advisor for development teams. Competitive benefits and flexible work opportunities are included.

Qualifications

• 5+ years in security engineering with hands-on experience in DevSecOps.
• Deep understanding of blockchain technologies and integration methods.
• Solid understanding of containerized infrastructure and Kubernetes.
• Proven experience working with cloud platforms and bare metal infrastructure.
• Strong knowledge of network security and encryption fundamentals.

Responsibilities

• Own and maintain internal security tooling.
• Design and maintain security controls across infrastructure.
• Continuously update threat models based on usage.
• Own access control systems for internal and on-chain resources.
• Stay updated with emerging vulnerabilities and test their impact.

Skills

Security engineering

DevSecOps

Blockchain technologies

Kubernetes

Cloud platforms

Network security

Encryption fundamentals

Identity and access management

SIEM platforms

Tools

AWS

GCP

HSM stores

SAST/DAST tools

IaC security scanning tools

Job description

We’re hiring a Security Engineer/Architect with Blockchain experience who thrives in fast-moving environments, understands
technical depth, and can independently own security across multiple areas — from architecture and infrastructure to monitoring and investigations.
You’ll be joining a lean team with serious responsibilities — context switching and high autonomy are part of the job. The role is ideal for someone who prefers deep thinking over surface-level “best practices”.
You’ll play a key role in securing our systems and eventually take ownership of technical implementation and decision-making.
We are building a range of products — from an advanced crypto payment solution evolving into a full blockchain ecosystem with real-world impact, to a comprehensive platform featuring its own blockchain, non‑custodial wallet, and stablecoin protocol designed for diverse use cases.

Requirements

• 5+ years in security engineering, with hands‑on experience in DevSecOps and, preferably, Web3;
• Deep understanding of blockchain technologies and integration methods.
• Solid understanding of containerized infrastructure, Kubernetes
• Proven experience working with cloud platforms (AWS, GCP, any experience with bare metal infrastructure will be a huge plus);
• Deep understanding of security principles, such as least privilege, defense in depth, secure defaults, and trust boundaries;
• Strong knowledge of network security (e.g., TLS, VPNs, firewall rules, intrusion detection);
• Familiarity with common vulnerabilities and exploit patterns (e.g., SQLi, XSS, CSRF, SSRF, RCE);
• Understanding of encryption fundamentals (symmetric/asymmetric cryptography, key rotation, secure storage);
• Practical experience with identity and access management (IAM, RBAC, MFA, OAuth2, SSO);
• Proven track record securing production infrastructure (and SDLC as a whole). This also includes implementation and maintenance of the following:
  • SIEM platforms;
  • SAST/DAST tools;
  • Infrastructure as Code (IaC) security scanning tools;
  • Secrets management (any experience with highly secure HSM stores will be highly appreciated);

Would be a plus

• Expertise in blockchain solutions, VMs, and smart contracts, any prior Solidity experience will be a huge plus;
• Experience with high‑performance transaction systems and distributed systems.
• Strong knowledge of microservices patterns, API design, and message brokers (e.g., RabbitMQ, Kafka).
• Familiarity with security policies and standards (e.g., NIST, ISO27001, CIS Benchmarks);
• Experience conducting or preparing for security audits or compliance assessments (SOC2, GDPR, etc.);
• Creating and maintaining playbooks for security incidents, access reviews, and response procedures;

Responsibilities

• Own and maintain internal security tooling (e.g., scanners, linters, alerting systems);
• Design, configure, and maintain security controls across infrastructure (firewalls, IAM policies, network segmentation);
• Continuously update threat models based on real usage and emerging attack patterns;
• Own access control systems for internal and on‑chain resources (e.g., multisig ops, key custody, signer policies);
• Perform static and dynamic analysis of codebases, including integrating SAST/DAST tools into CI/CD;
• Stay up to date with emerging vulnerabilities, test their impact on internal systems, and patch proactively;
• Drive the integration of inner account ecosystem projects, ensuring smooth operation;
• Work with DevOps and other product teams to secure cloud and containerized infrastructure;
• Participate in optimization of the platform’s performance, reliability, and fault‑tolerance capabilities;
• Act as a technical advisor, mentoring development teams and ensuring architectural consistency.
• Participate in design and implementation of secure architecture across all blockchain layers (Execution, Consensus, etc.);
• Manage security procedures for all core and periphery blockchain tools (explorer, validator portal, etc.);