Sentrio

The problem

Phishing and social-engineering attacks against banking customers rely on pages that look right at a glance — a look-alike domain, a convincing login form. Most people can't tell in the moment.

What it does

A Chrome extension that checks every page as you browse. It combines fast local checks, reasoning by a language model, and a trust profile it learns for each site, and warns you before you hand over your details.

How it works

The extension runs in layers. I built the extension shell and Layer 1, the local detection engine:

• A content script re-scans every page on load and on each change to the page.
• It runs zero-latency checks locally: a registry of verified bank domains, Unicode homoglyph detection (look-alike characters, such as Cyrillic letters disguised as Latin ones), detection of subdomain abuse, and a scanner for hidden text that tries to inject instructions into the AI agent.
• The results are packaged into a structured signal object that the reasoning layer (Groq, Llama 3.3 70B) works from.

Decisions

Fast checks run locally, before any AI. The local layer costs nothing and answers instantly; the language model is used for judgement, working from what the local layer found.

One AI call per meaningful change. Pages change constantly. Re-scanning is gated on a fingerprint of the page, so a busy page triggers a new AI call only when something that matters has actually changed.

The extension defends itself, too. An agent that reads web pages can be attacked through them. Layer 1 flags hidden text aimed at the AI before the AI ever sees it.