Head of Blockchain Security

About Bullish

Bullish is an institutionally focused global digital asset platform that provides market infrastructure and information services. These include:  Bullish Exchange – a regulated and institutionally focused digital assets spot and derivatives exchange, integrating a high-performance central limit order book matching engine with automated market making to provide deep and predictable liquidity. Bullish Exchange is regulated in Germany, Hong Kong, and Gibraltar.  CoinDesk Indices – a collection of tradable proprietary and single-asset benchmarks and indices that track the performance of digital assets for global institutions in the digital assets and traditional finance industries.  CoinDesk Data - a broad suite of digital assets market data and analytics, providing real-time insights into prices, trends, and market dynamics.  CoinDesk Insights – a digital asset media and events provider and operator of [Coindesk.com]( a digital media platform that covers news and insights about digital assets, the underlying markets, policy, and blockchain technology.

Chief Information Security Officer

We are looking for an exceptional Head of Blockchain Security to own and elevate the end-to-end security posture of our blockchain infrastructure, custody systems, and smart contract protocols.

In this role, you will operate as both a high-impact technical authority and a strategic partner to internal teams, protocol founders, and external security partners. You will design scalable security frameworks, lead complex audits across multi-chain environments, and engineer rapid-response mechanisms to protect assets in high-stakes environments. We operate lean, move fast, and value high emotional intelligence alongside deep technical rigor.

• Smart Contract Audit & Engineering: Lead deep-dive architectural reviews and security audits of smart contracts (Solidity, Rust, Move), focusing on protocol-level vulnerabilities. Oversee external third-party audits for high-complexity releases.
• Risk Advisory & Stakeholder Alignment: Produce clear, prioritized technical risk reports. Serve as the primary security advisor to protocol founders, engineering leads, and executive leadership, translating complex risks into actionable decisions.
• Toolchain & Automation Architecture: Build, deploy, and maintain robust blockchain monitoring, alerting, and automated detection systems across major ecosystems.
• Emergency Response & Crisis Readiness: Design and operate automated emergency exit workflows to protect protocol assets under adverse market or security conditions. Facilitate cross-industry incident response tabletop exercises.
• Custody, Treasury & Supply Chain Assurance: Conduct rigorous technical assessments of external institutional custody systems, internal treasury controls, and third-party vendor infrastructure.
• Scalable Operations: Build repeatable security frameworks and processes that enable our security program to scale seamlessly alongside aggressive organizational growth.

• Experience: 7+ years in cyber security, with 5+ years dedicated specifically to blockchain and smart contract security
• Technical Depth: Hands-on experience assessing smart contracts written in Solidity, Rust, and/or Move. Strong background in C/C++, Linux, and cloud native architectures (AWS, Azure, GCP).
• Security Discipline: Proven background in senior-level penetration testing, application security, offensive security methodologies, design reviews, and threat modeling (OWASP Top 10, SANS CWE 25) .
• Encryption & Network Infrastructure: Deep expertise in applied cryptography (PKI, algorithms, encryption at rest/in transit) and network/protocol fundamentals (IP, DNS, SSL/TLS)
• Multi-Chain Ecosystem Knowledge: Strong working knowledge of institutional custody infrastructure and major DeFi protocols across Ethereum, Solana, Stacks, and Sui.
• High EQ & Communication: Ability to articulate critical risks concisely to technical teams and non-technical stakeholders alike. Outstanding self-management and operational autonomy across global time zones.

• Offensive security certifications (OSCP, OSWE, OSCE) or related credentials.
• Track record of public security research, published vulnerability papers, or presentations at major industry conferences.