Security Engineer - Blockchain & Digital Assets

N3XT is a Wyoming-chartered Special Purpose Depository Institution (SPDI). We are a 100% reserved, non-lending bank designed to serve as a secure bridge between traditional capital markets and public blockchain infrastructure. Backed by Paradigm, HACK VC, Winklevoss Capital, and Pharsalus, we prioritize safety and transparency for institutional B2B clients. Position Summary As a Security Engineer focused on blockchain and digital assets, you will be the primary architect of our defense-in-depth strategy. You will secure the end-to-end lifecycle of our digital assets—from low-level cryptographic key management and node infrastructure to the auditing of high-level protocol logic. You will work closely with Infrastructure and Software teams to build automated surveillance systems that protect our "Hardened Production Environment". Key Responsibilities (Security & Research Focus) • Threat Modeling & Vulnerability Management: Proactively identify, assess, and mitigate security risks across our institutional-grade custody infrastructure and blockchain integrations. • Cryptographic Security Design: Design and audit secure key management architectures using FIPS 140-2/3 Level 3 HSMs and MPC/Threshold Signature Schemes. • Smart Contract & Protocol Auditing: Conduct rigorous internal audits and formal verification of smart contracts to prevent vulnerabilities like reentrancy, overflow, or logic errors. • On-Chain Surveillance & Incident Response: Build and maintain real-time monitoring tools to detect unauthorized private key usage, contract exploits, or anomalous liquidity movements. Lead the incident response process for all digital asset security events. • Security Policy & Compliance: Partner with Compliance to translate regulatory requirements (AML/KYC, SOC 2) into protocol-level technical controls. • Infrastructure Security Design: Ensure the integrity of our multi-provider node infrastructure by implementing strict network isolation (VPC), TLS pinning, and 2-of-3 validation checks. Operational & Engineering Responsibilities • Security Automation: Build and integrate automated security scanning, fuzz testing, and formal verification into our CI/CD pipelines. • Hardened Infrastructure: Utilize Terraform and Kubernetes to deploy secure, immutable infrastructure components. • Secure Governance Ceremonies: Design and oversee high-security "Key Ceremonies" and multi-signature governance workflows (Safe/Squads). What We’re Looking For • Cybersecurity & Blockchain Background: 5+ years in Information Security or Security Engineering, with at least 2 years focused on securing digital asset ecosystems or DeFi protocols. • Deep Cryptography Knowledge: Advanced understanding of cryptographic principles (Digital Signatures, Hash Functions, MPC, TSS). • Protocol Proficiency: Deep, demonstrable understanding of how different blockchains function at a protocol level (EVM and Solana). • Programming Expertise: Strong command of Solidity and Rust, with the ability to "think like an attacker" to find novel edge cases. • DevOps Fundamentals: Proficiency in Terraform, Kubernetes, and automated CI/CD workflows. Nice to Haves • Regulated Industry Experience: Prior experience in Banking or Finance-specific cybersecurity roles. • Incident Response: Experience with forensic analysis of on-chain exploits and cross-chain fund recovery. • Certifications: OSCP, CISSP, or specialized Blockchain Security certifications. Apply tot his job