Halborn

Halborn is a blockchain and digital asset security firm that provides smart contract audits, penetration testing, and advisory services to financial institutions and crypto protocols, and serves as one of Solana's longest-standing security partners.

What Halborn Does

Halborn offers end-to-end security coverage for blockchain projects and financial institutions building on digital assets. Its work falls into two broad categories: assurance services, which are hands-on technical reviews, and advisory services, which are strategic assessments and compliance programs.

On the assurance side, Halborn conducts smart contract assessments, full code security audits, Layer 1 blockchain reviews, web and cloud penetration tests, and red team exercises. On the advisory side, the firm delivers blockchain architecture assessments, custody and key management reviews, compliance readiness programs, technical due diligence for investors and acquirers, and AI security assessments.

This scope distinguishes Halborn from single-service audit shops. A project engaging Halborn can move from initial smart contract review through production penetration testing and into ongoing security monitoring without switching providers.

Track Record and Scale

Halborn reports protecting more than $1 trillion in client value across 800+ organizations and 4,000+ completed assessments. The firm has published five zero-day vulnerability disclosures. It holds ISO 27001:2022 certification and is SOC 2 Type 2 compliant, positioning it to serve regulated financial institutions alongside crypto-native clients.

Notable clients include Coinbase, Ripple, OKX, Circle, Grayscale, Stellar, Bank Frick, Sygnum Bank, and Banco Central do Brasil. The breadth of this client list reflects Halborn's positioning at the intersection of traditional financial security and blockchain infrastructure — it works with central banks on CBDC pilot hardening while simultaneously auditing DeFi protocols and Layer 1 validators.

The firm employs more than 100 security practitioners certified across CISSP, OSCP, OSCE, OSWE, OSEE, AWS, and CISA designations. It operates as a fully remote global organization.

Solana Ecosystem Fit

Halborn has one of the most extensive track records in Solana security. The firm's relationship with Solana Foundation and Solana Labs began with a Layer 1 assessment covering the Sealevel runtime from version 1.9, released in early 2022. Following that initial review, Halborn conducted incremental audits of new validator client code and SPL program updates prior to mainnet deployment.

The firm has audited more than 40 projects and applications built on Solana spanning DeFi protocols, infrastructure tooling, and gaming. Its SPL Token 2022 audit identified two critical vulnerabilities: one that allowed users to circumvent transfer fees, and another that allowed non-transferable tokens to be transferred. Both were remediated in coordination with the Solana Labs engineering team before the program deployed to mainnet.

Recent Solana-specific work includes security assessments of The Vault's directed stake program (completed February 2025), Huma Finance's Solana programs (March 2025 and December 2025), and an audit of 21BTC's Solana deployment. The ongoing engagement with Anza, the independent engineering firm that now develops the Agave validator client, continues Halborn's coverage of Solana's core execution infrastructure.

Services and Business Model

Halborn has evolved from offering standalone transactional audits toward what it describes as a Security-as-a-Service model, with retainer and ongoing monitoring arrangements suited to protocols deploying frequent upgrades. This model provides continuous incremental code review between point-in-time assessments, reducing the risk that new deployments ship without security coverage.

The firm has expanded into AI security, offering assessments and red team exercises targeting AI agent systems — including threats specific to agent-to-agent payment flows and AI reputation manipulation, which are emerging concerns in on-chain AI deployments.

Halborn has also built a SaaS product layer alongside its services practice, developed through its Halborn Labs R&D division, and previously acquired Abyss Consulting, a Web3 automation and rapid prototyping firm. These moves indicate an effort to build recurring technology revenue alongside project-based security engagements.

Team and History

Halborn was founded in 2019 by Rob Behnke and Steve Walbroehl. Walbroehl brought 25 years of cybersecurity experience, and Behnke came from a cryptocurrency and entrepreneurship background. The company was bootstrapped and profitable from its early years, reaching more than 100 employees without external capital.

In July 2022, Halborn raised a $90 million Series A led by Summit Partners — its first and only disclosed funding round at the time of writing. Participating investors included Castle Island Ventures, Digital Currency Group, Brevan Howard Digital, Third Prime, Sky Vision Capital, and Fenwick. The round valued the company at approximately $1 billion, making it one of the most heavily funded dedicated blockchain security firms.

In September 2024, Halborn announced the appointment of Jacques Boschung as CEO. Boschung, based in Switzerland, had a background in scaling technology organizations. Rob Behnke transitioned to the role of Executive Chairman and President, retaining an active role in company strategy.

Security Research and Publications

Halborn maintains an active research blog covering post-mortems on significant DeFi and blockchain security incidents. Recent content includes detailed technical breakdowns of oracle manipulation attacks, bridge exploits, hardware wallet breaches, and emerging AI agent threats. The firm publishes monthly DeFi hack roundups and has contributed to industry awareness of systemic vulnerabilities across ecosystems.

The combination of client work at the validator and protocol level with publicly shared research gives Halborn a dual function: active infrastructure defender and broader ecosystem educator.