Smart Contract Audits
Review of Solidity, Rust, and adjacent codebases with a focus on correctness, exploitability, protocol invariants, and fix validation.
Security Auditing & Consulting
Formal rigor for blockchain systems that matter.
Ostendo is a new blockchain security practice and the continuation of Decidable, led by Rikard Hjort. The firm is focused on smart contract audits, protocol review, formal methods, and high-signal security advice for teams building critical infrastructure.
Services
Work shaped for protocol teams, app teams, and difficult review surfaces.
Protocol & Architecture Review
Security analysis for bridges, lending systems, custom execution environments, and protocol upgrades before they harden into production risk.
Formal Methods
Invariants, executable specifications, property design, and targeted formal verification where mathematical assurance meaningfully changes the risk profile.
Security Consulting
Design review, audit preparation, incident-readiness thinking, and ongoing advice for teams that need deep technical judgment instead of checklist security.
Approach
Security work that starts with the invariants.
Ostendo is a small, senior practice focused on understanding what a system must guarantee, then reviewing code and design against those guarantees.
In practice that means fewer generic findings, more attention to invariants, more pressure on architectural assumptions, and clearer reasoning about what actually keeps funds and state safe.
Typical engagement areas
- Core protocol logic and upgrade paths
- Bridge and messaging assumptions
- Accounting, rounding, and invariant drift
- Wasm and non-EVM execution environments
- Audit-readiness and remediation review
Founder
Find out more about our founder.
Rikard Hjort has worked across blockchain security, audits, and formal methods. These links are a good place to start.
Runtime Verification
Listed as Security Advisor
Runtime Verification’s team page places Rikard Hjort among the company’s advisors.
Cantina Lead security researcher at SpearbitPublic Cantina profile describes independent audit work, prior Runtime Verification work, and formal verification experience.
Devcon 6 Formal Methods for the Working DeFi DevPublic Devcon workshop listing credits Rikard Hjort as the speaker in October 2022.
GitHub Formal methods & blockchainPublic GitHub profile and repositories reinforce the formal-methods and blockchain focus.
Contact
Early conversations are open.
If you are planning an audit, a sensitive launch, or a protocol change that deserves rigorous review, reach out directly. A more complete site and company materials are coming soon.