Founding Cryptography Engineer

PostQ; United States; Remote; USD 180,000 - 240,000; Full time

Benefits offered by this job

Remote-first role

Job summary

PostQ is seeking a senior cryptography engineer to own the core cryptographic systems of a post-quantum security platform. You will implement hybrid signing, PQC key exchange, and a verifiable transparency log, with an attested signing environment.

The role emphasizes correctness, auditable code, and clear rationale for security teams. The position requires strong Go skills (Rust preferred) and a track record of building security-sensitive systems.

Qualifications

• Strong Go programming skills.
• Rust experience preferred.
• Practical knowledge of cryptography, signatures, key encapsulation, hashing, X.509, TLS.

Responsibilities

• Design and implement hybrid signatures combining ML-DSA with Ed25519 or ECDSA, and ML-KEM key exchange.
• Build and maintain an RFC 6962 Merkle transparency log with consistency proofs and witness cosigning.
• Harden signing with envelope encryption, enclave attestation, and hardware-backed keys.
• Develop reference verifiers and keep behavior consistent across CLI, SDKs, and API.
• Apply NIST post-quantum cryptography standards and relevant specs in production code.

Skills

Go programming

Rust

Security architecture

Applied cryptography

Job description

Role overview

Own the cryptographic systems at the heart of a post-quantum security platform. This senior, high-trust role focuses on implementing hybrid signing, key exchange, a verifiable transparency log, and an attested signing environment. The work is expected to be correct, auditable, and clear enough for security teams to inspect closely.

Responsibilities

• Design and implement hybrid signatures combining ML-DSA with Ed25519 or ECDSA, and ML-KEM key exchange.
• Build and maintain an RFC 6962 Merkle transparency log, including consistency proofs and witness cosigning.
• Harden signing with envelope encryption, enclave attestation, and hardware-backed keys.
• Develop reference verifiers and keep behavior consistent across the CLI, SDKs, and API.
• Apply NIST post-quantum cryptography standards and relevant specifications in production code.

Requirements

• Strong Go programming skills; Rust experience is preferred.
• Track record building security-sensitive systems.
• Practical knowledge of applied cryptography, including signatures, key encapsulation, hashing, X.509, and TLS.
• Ability to read standards and RFCs and implement them accurately.
• Commitment to testable, auditable, well-documented code.

Nice to have

• Experience with confidential computing environments such as Nitro Enclaves or SGX, or with TPM 2.0.
• Contributions to open-source cryptography libraries.

Benefits and work setup

• Remote-first role open to US and EU time zones.
• Candidates are assessed on demonstrated ability rather than formal credentials.