Cryptography and Systems Researcher

Position: Senior Researcher / Scientist  ·  Location: Miami, FL strongly preferred  ·  Project: Char Network

About Char Network

Char Network is a proof-of-stake application coordination protocol built on Bitcoin. By anchoring data into Bitcoin through cryptographic proofs and economic guarantees, Char powers the next generation of Bitcoin layer twos and applications.

We’re a small, sharp, and adventurous team led by Bitcoin developer Jeremy Rubin, pushing the limits of what Bitcoin can be. Our work blends deep protocol expertise with a hacker’s creativity to unlock new capabilities for Bitcoin at scale.

We keep things collaborative, fast-moving, and fun—where every contribution counts and every voice matters. Joining Char means working at the frontier of Bitcoin R&D and infrastructure.

About the Role

This role sits at the intersection of research and engineering. You'll invent, formalize, and validate the core protocols that make Char Network work—from Byzantine fault tolerant consensus to staking incentive mechanisms to cryptographic proof systems.

Your focus is on the cryptographic foundations that make Char's protocol secure and efficient: designing and analyzing commitment schemes, aggregation protocols, proof systems, and fork-free coordination mechanisms. You'll work closely with the core protocol team to turn research into hardened, shipping software by building simulations, prototypes, and security specifications that guide implementation.

This is not a pure theory role, you'll write code.

What You’ll Do

• Design and analyze cryptographic schemes: BLS proof-of-stake commitments, signature aggregation protocols, hash-based accumulator designs, and zero-knowledge proof systems for Bitcoin anchoring


• Formalize consensus protocols for protocol security: fork-free properties, Byzantine fault tolerance guarantees, and commitment finality, with rigorous threat modeling and adversarial analysis


• Develop and validate cryptographic implementations: work with the protocol team to guide BLS Purify integration, verify protocol specifications against implementation, and conduct security reviews


• Build simulations and prototypes in Rust or C++ to validate cryptographic protocol designs under adversarial conditions: analyze safety/liveness properties and attack resilience


• Conduct formal cryptographic security analysis: threat modeling, game-theoretic attack analysis, and stress-testing through simulation and fuzzing to identify vulnerabilities before shipping

What We’re Looking For

Must-Haves

• Deep expertise in applied cryptography: signature schemes, commitment schemes, zero-knowledge proofs, or cryptographic protocol design


• Expert-level understanding of distributed systems theory: BFT consensus, fork-free protocols, Byzantine fault tolerance, and formal safety/liveness analysis


• Strong programming skills in Rust or C++ (or equivalent systems languages)


• Experience designing, analyzing, or breaking adversarial cryptographic protocols or consensus systems


• Ability to move between theory and practice: formal reasoning, mathematical modeling, and implementation


• Exceptional communication skills—you can explain complex cryptographic ideas clearly to both researchers and engineers

Nice-to-Haves

• PhD or equivalent research experience in cryptography, distributed systems, or a related field


• Prior contributions to Bitcoin, Ethereum, or other consensus-critical software


• Experience with formal verification, model checking, or advanced testing frameworks


• Published papers, technical reports, or BIPs in cryptography or distributed systems


• Understanding of Bitcoin primitives: taproot, timelocks, covenant designs, transaction scripting


• Experience with game-theoretic analysis or mechanism design (helpful for understanding protocol incentives)


• Strong open-source collaboration background

Reading Materials

Char Network

• MIT Bitcoin Expo Presentation (April 2026)


• Ember Consensus Paper


• Purify in purify-cpp

BitVM

• BitVM Whitepaper + BitVM2 Whitepaper


• BitVM High-Level Explainer