About the role
Lightspark is building the open payment protocol for the Internet making money move like data: instantly, globally, and without friction. With enterprise tools like Grid, Node, and Spark, businesses can send and receive money instantly, securely, and at a fraction of the cost, anytime, anywhere. Lightspark is headquartered in Los Angeles, California, but serves the world. We are seeking a Senior Security Engineer with a rare combination of deep infrastructure roots, application security expertise, and a sophisticated understanding of blockchain protocols. In this role, you will be architecting the safety of a high-throughput, decentralized payment network. Your expertise spans the entire security spectrum: you have the operational rigor to secure mission-critical infrastructure and the technical depth to audit low-level code, all while maintaining an intuitive grasp of on-chain anomalies and decentralized threat vectors. WHAT YOU’LL BE DOING: Secure Protocol Engineering: Perform deep-dive code audits and risk assessments of core protocol implementations and payment channel logic. You will prevent funds loss or state corruption by identifying edge cases in distributed systems. Hardened Infrastructure: Architect and secure our cloud-native footprint (AWS/GCP), ensuring that validator nodes, signing services, and P2P networking are resilient against both traditional DDoS and protocol-specific eclipse attacks. Application & Lifecycle Security: Build and maintain the Secure SDLC for our products. This includes automated security analysis (SAST/DAST) in CI/CD, managing high-stakes bug bounties, and performing manual penetration tests on our financial APIs. Cryptographic Operations: Design and manage mission-critical Key Management Systems (KMS). You will lead the implementation of Multi-Party Computation (MPC), Threshold Signatures (TSS), and HSM integrations to secure private keys at scale. Detection & Response: Develop specialized monitoring for both Cyber threats (unauthorized access, lateral movement) and On-chain threats (channel jamming, fee-siphoning, or routing anomalies). Security Expert: Serve as the subject matter expert for engineering teams, bridging the gap between standard web security and crypto-native security WHAT WE ARE LOOKING FOR: Experience: 6+ years in Security Engineering with a proven track record that spans Infrastructure, Application Security, and Blockchain/DeFi. Crypto Understanding: Hands-on experience with cryptographic primitives (Elliptic Curve, Schnorr, Merkle Trees) and a fundamental understanding of Layer 2 scaling (Lightning Network). Systems Programming: High proficiency in Python, Rust or Go . You should be capable of auditing systems-level code for memory safety, race conditions, and cryptographic flaws. Adversarial Expertise: A history of identifying vulnerabilities in decentralized protocols or high-scale distributed systems. You think three steps ahead of the attacker. Compliance & Frameworks: Understanding of how to apply traditional frameworks (NIST, OWASP) to the non-traditional world of decentralized finance and self-custody. Education: A CS degree is ideal, but we also value contributions to open-source security tools or a history of disclosed vulnerabilities in the crypto space. Communication: Ability to translate complex cryptographic risks into actionable engineering