The latest articles on DEV Community by A K (@a_k_a9a3d82011c50c554dfb6). https://dev.to/a_k_a9a3d82011c50c554dfb6 https://media2.dev.to/dynamic/image/width=90,height=90,fit=cover,gravity=auto,format=auto/https:%2F%2Fdev-to-uploads.s3.us-east-2.amazonaws.com%2Fuploads%2Fuser%2Fprofile_image%2F4192831%2F33d6bee0-f52e-46c1-b1a6-cacf357cf799.png https://dev.to/a_k_a9a3d82011c50c554dfb6 en A K Sun, 18 Oct 2026 20:25:38 +0000 https://dev.to/a_k_a9a3d82011c50c554dfb6/i-built-a-deterministic-01ms-ai-prompt-injection-firewall-and-seeded-an-open-500-usdc-bounty-214i https://dev.to/a_k_a9a3d82011c50c554dfb6/i-built-a-deterministic-01ms-ai-prompt-injection-firewall-and-seeded-an-open-500-usdc-bounty-214i <p>Most LLM guardrails (like Llama Guard or NeMo) add 500ms–1500ms of latency per call. For real-time autonomous AI agents, that delay kills the user experience.</p> <p>I built <strong>CanaryGuard</strong>: a deterministic heuristic firewall that inspects inputs in &lt;1ms line-rate before passing them to the model context.</p> <h3> What it Catches </h3> <ul> <li>Chat-template delimiter smuggling (<code>[INST]</code>, <code>&lt;|im_start|&gt;</code>, <code>&lt;&lt;SYS&gt;&gt;</code>)</li> <li>Concealed unicode obfuscation (zero-width spaces <code>\u200B</code>, bidi overrides)</li> <li>Hidden HTML/DOM injection (<code>display:none</code>, opacity tricks)</li> <li>Asset exfiltration &amp; wallet drain commands</li> </ul> <h3> Open Red-Team Challenge </h3> <p>To test how far deterministic rules hold up against real jailbreaks, I seeded an on-chain $5.00+ USDC bounty vault on Base &amp; Solana. If your payload slips past strict mode with status <code>clean</code>, you win the vault.</p> <p>👉 <strong>Test your payloads in the live simulator:</strong><br> <a href="https://canaryguard-402.onrender.com/bounty.html" rel="noopener noreferrer">https://canaryguard-402.onrender.com/bounty.html</a></p> <p><em>(Now includes a Sanitizer Mode toggle to see before/after text scrubbing live).</em></p> <p>Curious to hear what injection payloads you can use to break it!</p> ai webdev security