Blockchain Developer

Hybrid 4 days on site in New York, NY

Our client is building secure and scalable infrastructure for institutional digital finance. The team focuses on security engineering, cryptography, blockchain, and research-backed engineering that bridges theory and practice.

The Security Engineer will collaborate with cryptographers to design and implement a high-security, resilient crypto and tokenized assets custody solution, integrating secure protocols, MPC frameworks, and blockchain networks.

We can facilitate w2 and corp-to-corp consultants. For our w2 consultants, we offer a great benefits package that includes Medical, Dental, and Vision benefits, 401k with company matching, and life insurance.

Rate: $88.00 to $94.00/hr. w2

JN -072026-107749

Responsibilities

• Design and implement secure software and cryptography engineering for custody solutions.
• Collaborate with cryptographers to build secure and resilient MPC-based signing and key management workflows.
• Apply secure coding practices in C/C++, Go, or Rust with attention to side-channel and related attack resistance.
• Audit and integrate cryptographic libraries such as OpenSSL and MPC-specific libraries.
• Leverage hardware security features including Intel SGX, HSMs, and remote attestation.
• Develop and review threat models covering network and application attack vectors.
• Conduct crypto-focused code reviews and design tests for potential vulnerabilities.
• Integrate with blockchain nodes and APIs to assemble, sign, and broadcast transactions across networks.
• Handle blockchain transaction formats including Bitcoin UTXOs and Ethereum RLP.
• Implement secure storage patterns for encrypted key shares and audit logs.
• Build reliable networking and concurrency controls for communication among signing parties.
• Apply cloud security best practices and containerization for deployment.

Experience Requirements

• Expertise in secure software development and cryptography engineering.
• Proficiency in C/C++, Go, or Rust and secure coding practices.
• Hands-on use or audit of cryptographic libraries such as OpenSSL or MPC-specific libraries.
• Familiarity with Intel SGX, HSMs, and remote attestation.
• Experience with MPC or cryptographic frameworks used for crypto custody.
• Strong threat modeling capabilities and mitigation planning.
• Experience implementing or auditing cryptographic protocols such as key exchange or signature schemes.
• Knowledge of pitfalls including weak randomness and error handling that leaks information.
• Experience integrating with blockchain nodes and APIs.
• Understanding of Bitcoin UTXOs, Ethereum RLP, and transaction parsing and creation.
• Knowledge of secure storage and databases.
• Familiarity with cloud security and containerization.

Education Requirements

• Bachelor's degree.