Cryptographer - Security Engineer

Cryptographer – Security Engineering

Location: Remote
Company: Sigma Prime

About Sigma Prime

Sigma Prime is a boutique information security firm providing specialist expertise across blockchain systems and decentralised infrastructure. We are a team of developers, researchers, and security engineers.

Since 2015, we have worked at the forefront of blockchain security, reviewing Layer 1 and Layer 2 protocols, core cryptographic libraries, consensus systems, bridges, staking infrastructure, and advanced cryptographic constructions. We provide security reviews, design consultancy, and research services to leading organisations across the Web3 ecosystem.

We are also the creators and maintainers of Lighthouse, a leading Ethereum consensus client written in Rust and used in production globally. Lighthouse reflects our deep expertise in distributed systems, applied cryptography, and protocol engineering.

Our public audit reports can be found at:
https://github.com/sigp/public-audits/

The Role

We are seeking a Cryptographer – Security Engineer to join our security team.

This role is focused on auditing and analysing cryptographic protocols and implementations used in Web3 systems. You will work on cutting-edge distributed systems and zero-knowledge technologies, reviewing both protocol design and low-level implementations.

What You’ll Work On

You will perform in-depth security assessments of:

• Elliptic curve cryptography implementations

• Pairing-based cryptography

• Distributed Key Generation (DKG) protocols

• Threshold signature schemes (e.g., FROST)

• SNARK and STARK proving systems

• KZG commitments and polynomial commitment schemes

• Zero-knowledge circuits and proving infrastructure

• Consensus-critical cryptographic components

Our engagements often involve reviewing cryptographic libraries but are not specifically limited to only cryptography. There will be ample opportunity to work further through the web3 stack on core node infrastructure, smart contracts, cloud infrastructure and front-ends.

Example Past Cryptographic Engagements

• Filecoin – Drand DKG and threshold randomness protocol

• Filecoin – Proving Subsystem security review

• Ethereum Foundation – c-KZG & go-KZG libraries

• Ethereum Foundation – KZG Powers of Tau Ceremony

• Ethereum Foundation – BLS Wallet

• Lido – BLS Precompile Library

• Chainway Labs – Clementine (Bitcoin ↔ Citrea bridge using FROST DKG)

• Obol – Charon distributed validator client

Responsibilities

• Conduct technical security reviews of cryptographic protocols and implementations

• Analyse protocol-level designs for soundness and attack surface

• Review Rust, Go, and Solidity cryptographic implementations

• Identify subtle vulnerabilities in mathematical constructions and real-world implementations

• Write clear and precise security reports

• Contribute to internal cryptographic research and methodology

• Collaborate with protocol teams to improve security and design robustness

• Potentially contribute to internal open-source projects such as Lighthouse

Requirements

Strongly Preferred

• Advanced knowledge of applied cryptography

• Deep understanding of elliptic curves and finite field arithmetic

• Familiarity with pairing-based cryptography and BLS signatures

• Understanding of zero-knowledge systems (SNARKs, STARKs, PLONK, etc.)

• Experience analysing or implementing DKG or threshold signature systems

• Ability to read and reason about academic cryptography papers

• Strong systems programming skills (preferably Rust or Go)

Valuable Experience

• Reviewing or building cryptographic libraries

• Experience in consensus systems or distributed systems

• Formal methods or cryptographic proofs

• Experience contributing to open-source cryptographic software

• Prior security auditing experience

Programming Languages

Most common languages in our engagements:

• Rust

• Golang

• Solidity

Experience in C/C++, Python, or cryptographic DSLs is also beneficial.

Why Sigma Prime

• Remote-first team

• High-calibre technical peers

• Opportunity to work on foundational infrastructure securing billions in value

• Meaningful impact on the security of global decentralised systems

If you are passionate about applied cryptography and want to secure the next generation of decentralised systems, we would love to hear from you.