DFNS is the core banking platform for digital assets. Since 2020, we have helped fintechs and institutions build and operate onchain, with the security and reliability expected of systemically important firms. Our platform brings together everything required to run digital asset operations: wallets and key management, transaction processing, treasury, identity and access, policy and workflow orchestration, compliance integrations, and connectivity across 100+ blockchains. More than 400 institutions and fintechs run on DFNS, including Standard Chartered, First Abu Dhabi Bank, IBM, Broadridge, Apex Group, Stripe, Post Finance, Circle, and Susquehanna. The platform secures over €100B in assets and settles roughly 1% of global stablecoin volume. We're hiring a Principal Security Engineer to lead product security across the platform. Your job is to make security a property of the architecture itself, not a control bolted on afterward, across key management, signing workflows, authentication, policy enforcement, and blockchain integrations. You'll design new security capabilities, harden critical systems, and shape the long-term security architecture of a platform that regulated institutions bet their digital-asset operations on. Because we work in the open, you'll also contribute to the field through research, technical writing, and conference talks. This role goes beyond vulnerability management. You'll design new security capabilities, improve the resilience of critical systems, and help shape the long-term security architecture of the platform. Responsibilities Lead product security architecture across the platform, ensuring security is embedded into core system design. Analyze and secure the platform's key management, signing workflows, and transaction pipelines. Conduct system-level threat modeling for new features, protocols, and blockchain integrations. Design and review security-sensitive components such as auth systems, authorization models, and cryptographic workflows. Define and implement defense-in-depth controls across application, infrastructure, and protocol layers. Own and expand software supply-chain security, from dependency scanning in CI to package scanning on developer laptops. Drive infrastructure and security configuration into version-controlled code in GitHub to eliminate configuration drift. Work with engineering teams to ensure secure design decisions during product development and architectural planning. Investigate emerging risks across blockchain protocols, custody models, and cryptographic systems. Support ongoing SOC 2, ISO, and certification work as the platform's control surface grows. Support incident response and root-cause analysis for security-critical events. Provide day-to-day security support to developers, making the secure path the easy path. Represent DFNS in security architecture reviews with tier-one banks, auditors, and partners. Contribute to security research and knowledge sharing through articles, talks, or technical publications. Requirements 10+ years of experience in security engineering, product security, or security architecture. Experience securing financial infrastructure or blockchain platforms, ideally both. Strong understanding of cryptographic systems, wallet architectures, and key management models. Familiarity with MPC, threshold signatures, or HSM-backed key management is a strong advantage. Experience performing system-level threat modeling and security architecture reviews. Solid knowledge of distributed systems, networking protocols, and cloud infrastructure (AWS). Experience with software supply-chain security, package scanning, securing the dev environment end to end. Experience managing security and infrastructure configuration as code, with an eye for drift prevention. Familiarity with maintaining SOC 2, ISO 27001, ISO 22301, and related certifications in a live audit cycle. Knowledge of industry security frameworks such as the NIST Cybersecurity Framework. Strong understanding of authentication systems, authorization models, and applied cryptography. Experience working with modern backend languages such as TypeScript or Rust. Clear communicator able to translate complex security risks into practical engineering decisions. Recruitment Process Intro call with Co-CEO (30 min) Personality and cognitive tests (45 min) Coding test in a language of your choice Focus interview with the hiring panel (120 min) Threat model exercise Infrastructure security Culture fit check Final interview with CISO (30 min) Reference calls and background checks Terms Title: Principal Security Engineer Salary: $140,000–240,000 per year (full-time) Equity: 100–300 stock options vested over 4 years Benefits: Healthcare and travel expenses Location: US or EU (remote-first, office optional) Equipment: MacBook Pro + essentials