Senior Crypto Security Engineer

Lightspark • Culver City, CA

3d

About The Position

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.

Requirements

• 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 requirements for non-security peers.

Responsibilities

• 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 This Job Offers

• Job Type: Full-time
• Career Level: Senior