Layer 1 Blockchain Security Auditor

Company: Cyberscope, a TAC Security Company
Department: Web3 Security
Job Type: Full-Time
Experience: Minimum 4 Years
Role: Layer 1 Blockchain Protocol Security Auditor
Budget: 35000EUR/year

About CyberscopeCyberscope, a TAC Security Company, is a global Web3 security firm specializing in smart contract auditing, blockchain protocol security, penetration testing, and security assessments.We help blockchain projects, Web3 protocols, and digital asset platforms identify vulnerabilities, strengthen infrastructure, and build secure, resilient systems through advanced security research and practical testing.

Role OverviewWe are looking for an experienced Layer 1 Blockchain Security Auditor to assess the architecture, source code, and security of Layer 1 blockchain protocols and their core implementations.The ideal candidate will have strong programming skills, a deep understanding of blockchain internals and distributed systems, and hands-on experience in security auditing, vulnerability research, and exploit validation.This role focuses on Layer 1 protocol and core implementation security, rather than being limited to Solidity smart contract auditing.

Key Responsibilities1. Layer 1 Protocol Security
Review blockchain architectures, technical specifications, and core protocol source code.
Identify vulnerabilities in transaction processing, block validation, state transitions, and protocol execution.
Assess protocol correctness and identify logic flaws, unauthorized state changes, and implementation weaknesses.
Evaluate protocol upgrades, configuration changes, and modifications to core functionality.

1. Consensus and Distributed Systems Security
   Analyze Proof of Stake, Proof of Work, Byzantine Fault Tolerance, and other consensus mechanisms.
   Investigate risks involving validators, block production, finality, transaction ordering, and chain reorganizations.
   Assess double-spending, network partitioning, censorship, and conflicting chain states.
   Test protocol resilience against malicious validators, network failures, and adversarial conditions.

2. Node and Network Security
   Review blockchain node implementations, peer-to-peer networking, message handling, synchronization, and block propagation.
   Identify vulnerabilities involving malformed inputs, resource exhaustion, denial-of-service attacks, and malicious peers.
   Assess RPC endpoints, node APIs, and externally exposed interfaces.
   Investigate issues that could cause node crashes, network disruption, or inconsistent node behavior.

3. Cryptography and Transaction Validation
   Review hashing, digital signatures, public-key cryptography, and cryptographic library integrations.
   Analyze transaction authentication, signature verification, nonce management, replay protection, and transaction validity rules.
   Identify weaknesses in cryptographic implementations, key handling, serialization, and encoding.

4. Virtual Machines and Execution Environments
   Analyze execution environments, virtual machines, state transitions, and transaction processing.
   Review gas or resource accounting, execution validation, and interactions between consensus and execution layers.
   Identify vulnerabilities that could cause incorrect state updates, resource exhaustion, or inconsistent execution across nodes.

5. Vulnerability Research and Security Testing
   Conduct manual code reviews, security assessments, and independent protocol security research.
   Develop proof-of-concept exploits to validate vulnerabilities and demonstrate practical impact.
   Perform fuzzing, property-based testing, regression testing, and adversarial scenario testing where appropriate.
   Reproduce security issues, validate fixes, and contribute to internal security tools and automated testing methodologies.
   Research blockchain exploits, security advisories, CVEs, and protocol incident post-mortems.

6. Reporting and Collaboration
   Prepare detailed security audit reports documenting vulnerabilities, severity, impact, reproducible steps, and remediation recommendations.
   Communicate technical findings clearly to developers, clients, and internal stakeholders.
   Collaborate with blockchain engineers and security researchers to validate findings and improve security practices.
   Contribute to technical research, internal knowledge sharing, audit methodologies, and mentoring junior team members where required.

Required Technical Skills
Minimum 4 years of relevant experience in blockchain development, protocol security, security auditing, vulnerability research, or security engineering.
Strong understanding of blockchain fundamentals, including transactions, blocks, nodes, state transitions, and distributed ledgers.
Practical knowledge of consensus mechanisms and distributed systems security.
Proficiency in at least one programming language: Rust, Go, or C++.
Ability to analyze, debug, and understand complex codebases.
Understanding of cryptographic primitives, digital signatures, transaction validation, and public-key cryptography.
Knowledge of networking, peer-to-peer communication, and distributed node architectures.
Familiarity with software vulnerabilities, input validation, denial-of-service risks, and common attack vectors.
Experience identifying vulnerabilities and validating findings through practical testing or proof-of-concept development.
Familiarity with Git, Linux, command-line tools, debugging, and software testing workflows.
Strong analytical, problem-solving, and technical documentation skills.

Preferred Qualifications
Hands-on experience auditing Layer 1 protocols or blockchain client implementations.
Experience with Rust-based blockchain clients; exposure to Go or C++ implementations.
Understanding of validator infrastructure, client interoperability, protocol upgrades, and finality mechanisms.
Experience with fuzzing, property-based testing, formal verification, debugging, or automated security testing.
Familiarity with ecosystems such as Ethereum, Solana, Cosmos, Polkadot, or other Layer 1 architectures.
Contributions to blockchain open-source projects, security research, CTFs, bug bounty programs, or responsible vulnerability disclosures.
Experience writing technical security reports and presenting findings to engineering teams.

EducationA bachelor's degree in Computer Science, Information Technology, Cybersecurity, Software Engineering, or a related field is preferred. Equivalent practical experience and demonstrable technical expertise will also be considered.

Why Join Cyberscope?
Work on real-world Layer 1 blockchain and Web3 security challenges.
Gain exposure to protocol internals, distributed systems, and advanced vulnerability research.
Collaborate with experienced security researchers and blockchain engineers.
Build expertise in security auditing, exploit validation, and protocol-level testing.
Grow toward senior auditing, specialized security research, and technical leadership opportunities.

Join Cyberscope and help build a more secure blockchain ecosystem.