Product Security Engineer

About Hashgraph: Hashgraph is a fast-growing software company committed to supporting, developing and servicing Hedera, an open source, proof-of-stake platform. Hedera is EVM-compatible and has been specifically built to meet the needs of enterprise and web3 applications, which require speed, security, stability and sustainability. Hedera’s public network is governed by industry-leading organizations, spanning 11 sectors and 14 regions who oversee the development and direction of the decentralized platform. The role: We are hiring a Product Security Engineer to embed security into the product development lifecycle and ensure vulnerabilities are found by us before they are found by others. Hedera is an enterprise-grade distributed ledger securing billions of transactions for global developer and institutions. As the platform grows with new protocol upgrades, EVM-compatible services, cross-chain infrastructure, and cryptographic primitives, the attack surface grows with it. This role exists to ensure that security is a first-class property of every protocol upgrade, smart contract, and node shipped to production. In this role, you will: Conduct end-to-end security assessments of blockchain-based systems, from cryptographic primitive design and protocol architecture through smart contract implementation and deployed infrastructure. Find real vulnerabilities through hands-on review, adversarial testing, and proof-of-concept exploit development, not just automated scanning. Design adversarial test cases and proof-of-concept exploits for Hedera-native services, EVM-compatible contracts, cross-chain bridges, and consensus-layer components. Own threat modeling and security architecture reviews across product phases. Define and enforce security gates before new components reach production. Partner directly with engineering teams to translate cryptographic and protocol-level risks into concrete, prioritized remediation work. Build and improve security tooling, fuzzing infrastructure, and CI/CD security automation to scale security coverage without scaling headcount. Track emerging blockchain and web3 attack patterns, map them to the internal codebase, and drive proactive mitigation before threats materialize. What success looks like in 6-12 months: Security review processes are integrated across major product development workflows, not bolted on at the end. Security tooling and automated checks are running inside CI/CD pipelines, reducing manual review burden. The vulnerability backlog is prioritized and actively shrinking through structured developer collaboration. Engineering teams have meaningfully improved their working knowledge of web3 attack patterns and secure coding practices. What you bring: Core capabilities: Hands-on vulnerability discovery and security testing across blockchain protocols, smart contracts, nodes, and APIs. A track record of catching real bugs, not just running automated scans. Strong threat modeling and security architecture review experience applied to distributed cryptographic systems. Experience assessing cross-chain protocols, threshold signature schemes, or other cryptographic systems with complex trust assumptions. Deep working knowledge of applied cryptography, including BLS signatures, pairing-based schemes, polynomial commitments, and Fiat-Shamir constructions. Ability to reason about cryptographic failure modes and how they show up in production systems. Direct experience auditing or breaking a cross-chain bridge. Ability to reason through trust model tradeoffs, including state proof, multisig, and oracle attestation models, and what each means for the attack surface. Functional expertise: Blockchain security and secure coding practices across EVM-compatible and non-EVM chains. Security testing tooling, including static analysis, dynamic analysis, and fuzzing. Experience developing custom fuzzing harnesses or security test infrastructure. Ability to read and audit Rust and/or Java cryptographic cod