Cybersecurity Engineer, Cryptography

Remote, South Africa

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...