Michael Lewellen is an American blockchain security engineer, technology executive, and educator who serves as Head of Solutions Engineering at Turnkey. His career has focused on blockchain infrastructure, smart contract security, enterprise software, digital asset technologies, and blockchain education. ^[1]

Education

Lewellen earned his Bachelor's in Computer Science from the University of Texas at Dallas. ^[2]

Career

Lewellen began his career as a web developer at The University of Texas at Dallas from 2016 to 2017, where he developed university websites and supported academic research involving SEC filing analysis and fraud detection. In 2018, he worked as a blockchain developer for Thomson Reuters, contributing to blockchain-based tax systems, Ethereum smart contracts, and proof-of-concept applications for tax compliance. He later served as Chief Technology Officer and Software Architect at Olypsis, where he designed blockchain applications and enterprise software architectures for sectors including supply chain management, taxation, and real estate.

Between 2018 and 2021, Lewellen co-founded Tarski Technologies, where he led technology strategy and consulting projects focused on blockchain, artificial intelligence, automation, and enterprise software. During this period, he also worked on contract engagements as Lead Software Architect for Toyota North America, developing blockchain-based supply chain systems, and as Blockchain Architect and Technical Lead for Verizon, where he led development of a blockchain-based claims management platform. In 2020, he joined the Board of Directors of the Texas Blockchain Council and began serving as a part-time lecturer at the University of Texas at Dallas, teaching graduate-level courses on blockchain technology and cryptocurrencies. He has also operated Cryptocurrency Consulting as an independent consulting practice, advising organizations on blockchain technologies.

Lewellen joined OpenZeppelin in 2021 as Security Project Manager, overseeing smart contract security audits and blockchain security initiatives. He later served as Protocol Security Advisor, supporting security monitoring and governance initiatives, before becoming Head of Solutions Architecture in 2022. In that role, he led technical architecture, client advisory work, research, and the development of blockchain security solutions while managing engineering and solutions architecture teams.

In 2025, Lewellen became Head of Solutions Engineering at Blockaid before joining Turnkey later that year as Head of Solutions Engineering. He also became Chief Technology Officer of Ion Strategies on a part-time basis. Across his career, his work has centered on blockchain security, smart contract development, enterprise blockchain systems, digital asset infrastructure, and technical education. ^[3]

Interviews

DeFi Security Risks

In an April 2026 livestream interview with Certora CEO Seth Hallem, Lewellen discussed evolving security challenges in the cryptocurrency industry, focusing on the growing importance of off-chain vulnerabilities alongside smart contract security. The conversation examined how attackers increasingly target operational infrastructure, including key management systems, endpoints, multi-signature processes, and other components outside blockchain protocols. Lewellen and Hallem discussed recent security incidents and the rise of sophisticated threat actors, including state-linked groups, using methods such as social engineering, malware, and infrastructure compromises. They emphasized that effective security requires broader threat modeling, stronger operational controls, and improved protection of off-chain systems rather than relying solely on smart contract audits. The discussion also explored the impact of artificial intelligence on blockchain security, noting that AI can accelerate vulnerability discovery for both attackers and defenders while introducing new risks such as automated exploitation and prompt injection attacks. Lewellen highlighted the need for responsible AI adoption, secure operational practices, endpoint protection, and education to maintain security while preserving the benefits of decentralized systems. ^[5]

Lewellen vs. DOJ

At the DC Privacy Summit in October 2025, Lewellen participated in a fireside chat with Mike Orcutt of Project Glitch, discussing cryptocurrency privacy, security, and regulatory challenges. Lewellen described his background as an early Bitcoin miner and smart contract developer, with experience in blockchain security audits and policy advocacy, and explained that concerns over potential legal risks influenced his involvement in privacy-preserving blockchain development. He discussed the role of crypto security councils, describing them as trusted multi-signature groups that help coordinate protocol upgrades, emergency responses, and security improvements while maintaining decentralized governance. Lewellen examined the regulatory impact of cases such as Tornado Cash, arguing that enforcement actions created uncertainty for developers and discouraged experimentation with privacy technologies. He also discussed his legal efforts to clarify the regulatory status of privacy-focused protocols and advocated for legislative reforms, including the Blockchain Regulatory Certainty Act, to establish clearer protections for developers. The conversation concluded with a discussion of cybersecurity challenges in Web3, including the need for improved key management, user education, and infrastructure that balances self-custody with usability and security. ^[6]

Presenations

Privacy Is Not a Crime

At the Privacy & Compliance Summit in December 2025, Lewellen discussed the intersection of cryptocurrency privacy technology, regulatory policy, and security practices. Drawing from his experience in smart contract auditing and policy discussions, including involvement with Coin Center’s legal efforts related to Tornado Cash, Lewellen examined the challenges developers face when building privacy-preserving systems within an uncertain regulatory environment. He highlighted conflicting interpretations among U.S. agencies regarding whether privacy protocols qualify as money transmitters, noting that unclear guidance creates challenges for developers and operators of privacy-focused technologies. Lewellen discussed legal efforts to establish clearer protections for privacy technology development and referenced proposed legislation aimed at providing greater regulatory certainty. He also addressed international regulatory developments, including the European Union’s MiCA framework, and explored privacy-preserving compliance approaches such as Privacy Pools, which seek to maintain user privacy while reducing opportunities for misuse. Lewellen argued that privacy technologies can provide benefits for security and regulatory oversight when supported by appropriate frameworks, and emphasized the importance of collaboration between developers, policymakers, and regulators in shaping future cryptocurrency regulation. ^[7]

Panels

Securing Billions

At ETHBoston in September 2025, Lewellen participated in the “Securing Billions” panel alongside Yolanda Liu from Coinbase and Anders Brownworth from Radius, moderated by Samara LeMerle from Cantina. The discussion focused on the challenges of securing large-scale blockchain systems and the need for security approaches that extend beyond traditional audits through layered defenses, continuous monitoring, and internal accountability. Panelists emphasized the importance of proactive threat modeling, recurring security assessments, and strong organizational ownership to identify vulnerabilities and prevent operational issues within decentralized protocols. They also discussed the role of observability tools and on-chain monitoring in detecting early indicators of compromise and improving incident prevention. The panel addressed the balance between regulation, industry standards, and innovation, highlighting the need for adaptable security frameworks and greater education across the blockchain ecosystem. Lewellen and the other panelists also shared examples of security failures, discussed the importance of private key management, and emphasized operational security practices, consensus mechanisms, and comprehensive incident response planning. ^[8]