Security Engineer, Institutional Trading

As a Security Engineer embedded with the Institutional Trading and Financial Operations team at Blockchain, you focus on the secure operation of off-chain trading processes and infrastructure that powers the institutional business. You will work on integrations, signing flows, key custody interfaces, middle-office workflows, order routing and settlement pipelines that handle significant capital. Your responsibility is operational security engineering, ensuring that the tools and processes traders use are resilient against both external threats and internal errors. This role does not require smart-contract auditing.

What you'll do

• Partner with Trading, Middle Office and Quant teams to map out inventory trading systems, data flows, third-party integrations and custody/settlement touchpoints.
• Conduct deep-dive assessments to identify structural vulnerabilities in critical assets and workflows, define the Target State and draft strategic Risk Treatment Plans required to meet institutional-grade standards such as CCSS, NIST and DORA.
• Act as the primary security liaison for Senior Management and third-party vendors, translating complex technical gaps into actionable business risk summaries, driving vendor evaluations for core security infrastructure, and managing project lifecycles for high-impact posture improvements.
• Implement and maintain monitoring for FinOps-specific security signals such as abnormal order patterns, signature misuse and unusual settlements, integrating these signals into SIEM/SOAR for real-time response.
• Support secrets and key-management hygiene by ensuring app and service keys are stored in KMS/Vault, scoped to least privilege and rotated automatically to prevent credential leakage.
• Assist product security in triaging SAST/SCA findings for FinOps-related repositories and help implement CI checks and remediation playbooks.
• Participate in incident exercises, post-incident reviews and remediation tracking for trading incidents.
• Document controls and produce concise risk summaries for FinOps leads and the Security team.
• Research, architect and safely embed cutting-edge AI utilities and Large Language Model agents directly into the secure infrastructure.

What you bring

• 5+ years of experience in security engineering, platform security or application security.
• Proven expertise in Threat Modeling and ability to perform structured reviews such as STRIDE of complex data flows and operational processes.
• Experience with observability and detection tooling (SIEM, logs, metrics) and ability to write basic detection rules.
• Practical experience with KMS/HSM, secrets management platforms such as Vault, 1Password, AWS/GCP KMS, IAM patterns and least-privilege access.
• Exceptional ability to translate technical debt into business risk for C-suite stakeholders (CFO, CTO, Head of Trading).
• Ability to raise, read and audit Pull Requests in at least one language used in the stack (TypeScript, Java/Kotlin, Python).
• Experience conducting technical due diligence and scoping for third-party security integrations.

Nice to have

• Familiarity with trading systems or financial operations such as market-making, execution and settlement, or a track record of close collaboration with trading and quant teams.
• Exposure to blockchain on-chain concepts (wallets, addresses, transactions), though no requirement to audit contracts.
• Familiarity with SOC operations and post-incident forensic analysis.
• Familiarity with SOC2, ISO 27001 or financial audit requirements.
• Any relevant industry certification.

What we offer

• Unlimited vacation policy.
• Unlimited books policy for technical resources.
• Apple equipment.
• Full-time salary based on experience and meaningful equity in Blockchain.
• Role based in the Paris office with mandatory in-office presence four days per week.
• Work from Anywhere Policy allowing remote work from anywhere in the world for up to 20 days per year.

About Blockchain

Blockchain connects the world to the future of finance. Since 2011, it has earned the trust of over 90 million wallet holders and more than 40 million verified users, facilitating over $1 trillion in crypto transactions.