Cybersecurity Engineer, Cryptography

Client: US technology company (digital identity and payments infrastructure) · Location: remote, LATAM, US Eastern overlap · Level: senior · Engagement: full-time contractor

You will own applied cryptography across the product: key management, protocol design review and the migration plan to post-quantum algorithms.

What you will do

• Design and operate key management on HSMs and cloud KMS, including rotation, escrow and ceremonies

• Review protocol and feature designs for correct use of encryption, signatures and key exchange

• Run PKI: certificate authorities, issuance automation and mTLS between services

• Build the crypto inventory and lead the roadmap to NIST post-quantum standards (ML-KEM, ML-DSA)

• Maintain internal crypto libraries and guidance so product teams do not roll their own

• Support audits and certifications such as FIPS 140-3, PCI DSS and SOC 2

What you bring

• 6+ years in security engineering, 3+ focused on applied cryptography

• Solid command of modern primitives and protocols (AES-GCM, ECC, TLS 1.3, Noise, JOSE)

• Hands-on HSM and KMS experience (Thales, AWS CloudHSM, AWS KMS or equivalent)

• Coding in Go, Rust or C, with secure coding and code review experience

• Ability to explain cryptographic risk to non-specialists in English

Nice to have

• Threshold signatures, MPC or zero-knowledge proof experience

• Degree or research background in cryptography

• Contributions to open-source crypto libraries