Research Engineer, Cryptography

About the Company:

World is a network of real humans, built on privacy-preserving proof-of-human technology, and powered by a globally inclusive financial network that enables the free flow of digital assets for all. It is built to connect, empower, and be owned by everyone.

This opportunity would be with Tools for Humanity.

The Protocol team at TFH consists of a group of engineers focused on shipping production-grade systems at the edge of cryptography, Ethereum/L2s, and zero-knowledge. We design and implement trustless, decentralized, and privacy-preserving systems that are built to scale to billions of users. Our work powers World ID, World Chain and other protocols within the World ecosystem, pushing the boundaries of what’s possible with decentralized identity and blockchain scalability. We regularly collaborate with leading teams in the Ethereum ecosystem as well as contribute to open research and protocol design.

*This role is onsite based in our San Francisco, CA office

We’re looking for a Research Engineer to join the Applied Research team at TFH, working at the cutting edge of cryptography to help scale and secure World ID and the World protocol. This role bridges theory and implementation — ideal for someone with a strong academic background in math, with a particular exposure to cryptography, complexity theory, or decentralized privacy, who also thrives in building real systems.

You’ll help prototype and deploy novel cryptographic primitives that enable privacy-preserving identity, scalable data availability, and secure manufacturing—translating ambitious ideas into production-ready code. Recent projects include ZK iris-code upgrades, ZK-based DA layers, and decentralized randomness for hardware provisioning. Rust experience is a plus, as is familiarity with zero-knowledge proof systems, MPC, and AI/ML.

This is a rare opportunity to shape the foundations of a global identity system while collaborating with a small, rigorous, and kind team pushing the boundaries of what’s possible in applied cryptography.

• Design, prototype, and implement novel cryptographic protocols that enable privacy, scalability, and trust in the World ecosystem

• Translate research into high-quality, production-adjacent reference implementations (Rust preferred)

• Collaborate closely with research, engineering, and product teams to scope technical projects that push the protocol forward

• Evaluate and mitigate security, integrity, and privacy risks across key systems, including World ID, World Chain, and Orbs

• Contribute to architectural decisions around decentralized identity, data availability, and trusted hardware provisioning

• Stay abreast of emerging research and propose new areas of exploration or implementation

• Engage in mutual mentorship: raise the bar for rigor while supporting the growth of others on the team

• You have a strong research background in cryptography, theoretical computer science, or a related field — especially in areas like zero-knowledge proofs, MPC, FHE, complexity theory, or secure systems

• You're comfortable moving between whiteboard proofs and real-world code, and you have experience writing clear, efficient implementations (Rust is a plus, but not required)

• You care deeply about rigor, security, and the broader implications of your work—both technical and ethical

• You’re collaborative, humble, and intellectually generous—you enjoy learning from others and helping them grow too

• You’re energized by hard problems and ambitious missions, and you’re excited to shape how cryptography impacts the future of identity at a global scale

• Bonus: you’ve explored intersections with AI/ML or have experience working in multi-disciplinary teams bridging research and engineering

• An open and collaborative office space in downtown SF 

• Unlimited PTO  

• Monthly Phone Reimbursement or a company device

• Daily in-office meals 

• Top-tier medical, dental, vision insurance 

• 401k + employer match program 

Pay transparency statement (for CA and NY based roles): 

The reasonably estimated salary for this role at TFH in our San Francisco office ranges from $170,000 - $275,000, plus a competitive long term incentive package. Actual compensation is based on factors such as the candidate's skills, qualifications, and experience. In addition,  TFH offers a wide range of best in class, comprehensive and inclusive employee benefits for this role including healthcare, dental, vision, 401(k) plan and match, life insurance, flexible time off, commuter benefits, professional development stipend and much more!