Blockchain Backend Security Engineer

Design the future architecture of one of Europe's most innovative banking networks while empowering engineers to do their best work.

We are looking for a highly experienced Blockchain Backend Security Engineer with strong security expertise to help build and scale ING's Digital Asset Services (DAS) platform. The role will play a critical part in designing and implementing secure custody and wallet management capabilities for digital assets, integrating with blockchain SaaS platforms and ensuring enterprise‑grade security controls across the platform.

This position is part of the initial DAS delivery milestone, focusing on blockchain SaaS integration, wallet management, custody workflows, and secure key lifecycle management.

At ING Hubs Türkiye, flexibility is more than a benefit—it's part of how we work.

Our hybrid way of working is designed to balance collaboration, innovation, and personal flexibility. Team members typically come together at our Vadistanbul office for two days per week during three weeks of the month, while one week each month is fully remote.

We also provide additional flexibility throughout August with remote working opportunities, allowing colleagues to remain productive while staying connected with their teams.

As part of a globally distributed organization, you'll collaborate with colleagues across multiple ING locations and contribute to solutions used across the bank.

You will join an international technology organization where ownership, knowledge sharing, collaboration, and engineering excellence are at the heart of everything we do.

Our teams design and deliver critical technology platforms that support ING's digital transformation journey. We believe scalable architectures, strong engineering practices, automation, and continuous learning are essential for delivering reliable solutions at scale.

• Bachelor's degree in Computer Engineering, Software Engineering, or a related discipline
• Fluent English communication skills (C1 level or above)
• 5+ years of professional software engineering experience.
• Strong hands‑on experience with Java (Java 17+ preferred).
• Experience with Spring Boot and microservice architectures.
• Strong knowledge of RESTful APIs and event‑driven architectures.
• Good understanding of container technologies (Docker, Kubernetes).

• Experience with MPC (Multi‑Party Computation) custody solutions.
• Experience integrating institutional custody providers.
• Knowledge of blockchain security and smart contract risks.
• Experience with cloud platforms (Azure preferred).
• Familiarity with ISO 27001, SOC2 and financial security standards.
• Experience working in Agile/Scrum environments.

• Design, develop and maintain Java‑based backend services supporting digital asset operations.
• Build APIs and microservices for wallet administration, asset transfers, transaction signing and custody workflows.
• Develop integration components with blockchain SaaS vendors and custody providers.
• Ensure high availability, scalability and resilience of critical digital asset services.

• Design secure key management processes across the entire key lifecycle.
• Implement integrations with HSMs (Hardware Security Modules), vault solutions and key custody platforms.
• Support cryptographic operations including transaction signing, encryption and secure key storage.
• Apply security‑by‑design principles throughout application development.
• Conduct security reviews and threat modeling for new capabilities.

• Design and implement wallet provisioning and lifecycle management capabilities.
• Build and optimize custody workflows for institutional digital asset operations.
• Support…