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Back End Developer

Synthesis Software Technologies

Location

City of Johannesburg, Gauteng, South Africa

Salary

Not specified

Type

fulltime

Posted

Today

via linkedin

Job Description

Cryptography Engineer (Intermediate / Senior)

Shape the Future of Payment Security

Are you passionate about cryptography, security engineering, and building systems that protect millions of transactions every day?

We're looking for an

Intermediate Cryptography Engineer

to join our growing team and help design, implement, and support secure cryptographic solutions for payment and financial services environments. This is a unique opportunity to work at the intersection of

applied cryptography, payment security, HSM integration, and backend engineering

, tackling complex security challenges in production environments.

If you enjoy solving difficult technical problems, working with industry standards, and turning cryptographic theory into real-world solutions, we'd love to hear from you.

What You'll Do

As a Cryptography Engineer, you will:

✅ Design and develop cryptographic services and secure backend solutions

✅ Integrate applications with enterprise HSMs and cryptographic infrastructure

✅ Implement key management and key lifecycle processes

✅ Work with payment cryptography technologies including:

  • PIN Blocks
  • DUKPT
  • CVV/CVC
  • PVV
  • EMV

✅ Implement and troubleshoot industry standards such as:

  • TR-31
  • TR-34

✅ Investigate security and cryptographic incidents

✅ Conduct security-focused code reviews and testing

✅ Collaborate with clients and technical partners on integration projects

✅ Participate in architecture, security, and technical design discussions

✅ Research emerging cryptographic technologies and security innovations

✅ Create and maintain technical documentation and implementation guides

What You Bring

Cryptography \& Security

You have a strong understanding of:

  • Symmetric and asymmetric cryptography
  • AES, RSA, ECC
  • Hashing, HMAC and key derivation
  • Cryptographic key management and lifecycle processes
  • Secure random number generation
  • PKI, TLS and authentication frameworks
  • Secure software development practices
  • Threat modelling
  • Common implementation vulnerabilities and mitigation strategies

Payment Security

Experience or knowledge of:

  • Payment HSMs
  • TR-31 and TR-34
  • PIN block formats
  • DUKPT
  • CVV/CVC and PVV generation
  • EMV cryptography
  • Payment key hierarchies
  • Key ceremonies

⭐ Experience with

Thales payShield HSMs

is highly advantageous.

Software Engineering

Strong proficiency in one or more of:

  • TypeScript / JavaScript
  • Java
  • Go
  • C/C\+\+
  • Python

Along with experience in:

  • Backend application development
  • REST API design and integration
  • Linux environments
  • Git-based development workflows
  • Automated testing
  • Networking fundamentals
  • Distributed systems
  • Observability, logging, metrics and tracing

Bonus Points For

While not required, we'd love to see experience with:

  • Kubernetes
  • Docker and containerisation
  • CI/CD pipelines
  • Infrastructure as Code
  • Cloud platforms and cloud security
  • Linux administration
  • Secrets management
  • Monitoring and observability tooling

Industry \& Standards Knowledge

Exposure to the following standards is highly valued:

  • PCI PIN / PCI PTS
  • PCI DSS
  • ISO 9564
  • ISO 8583
  • ISO 20022
  • ANSI X9
  • EMV Standards
  • PKCS Standards

Research \& Emerging Technologies

We encourage innovation and continuous learning. Interest or experience in any of the following is a significant advantage:

  • Trusted Execution Environments (TEEs)
  • Passkeys \& WebAuthn
  • Zero-Knowledge Proofs (ZKPs)
  • Fully Homomorphic Encryption (FHE)
  • Confidential Computing
  • Post-Quantum Cryptography
  • Hardware-Backed Security

We value curiosity and the ability to independently learn complex concepts just as much as prior exposure.

Minimum Requirements

✔ Bachelor's degree in Computer Science, Computer Engineering, Electrical Engineering, Mathematics, Cybersecurity, or a related field

✔ 2\+ years of professional experience in software engineering, cryptography, or security-related roles

✔ Experience building and supporting production systems

✔ Strong foundations in computer science, cryptography, and security engineering

✔ Ability to independently solve complex technical challenges

Ideal Candidate

You're an applied cryptographer who enjoys building real-world systems.

You can take a cryptographic requirement, understand the underlying security model, identify the required keys and cryptographic operations, integrate with an HSM, develop supporting backend services, thoroughly test the solution, and troubleshoot issues in production.

Core Skill Profile

Cryptography \+ HSMs \+ Payment Security \+ Backend Engineering \+ Security Engineering

Additional expertise in Kubernetes, DevOps, and cloud infrastructure is advantageous but not essential.

Why Join Us?

  • Work on mission-critical payment and security systems
  • Solve highly complex technical challenges
  • Collaborate with experts in cryptography and fintech
  • Exposure to cutting-edge security technologies
  • Opportunities for professional growth and research
  • Make a meaningful impact in a fast-growing, security-focused environment

Ready to build the future of secure payments?

Apply today or reach out directly for a confidential conversation.

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