AI Prompt Security Layer POC

Client-side redaction logic that strips sensitive data — API keys, tokens, passwords — from text before it's sent to an LLM.

Paste text containing credentials into the input pane, configure marker-based redaction rules (Bearer headers, query params, JSON fields, etc.), and the tool replaces matched values with [REDACTED] instantly.

Features

• Runs entirely in the browser (client-side); nothing gets sent to a server

• Loads your C++ redaction engine compiled to WebAssembly (redactor.wasm) via redactor.mjs

• Lets a user build a redaction ruleset in a left-side “Rules” panel

• Supports rule types:

  • Bearer auth header redaction (Authorization: Bearer …)
  • Generic header value redaction (Header-Name: …)
  • Query parameter redaction (api_key=… with stop characters like &/whitespace)
  • JSON field redaction ("token":"…" stopped by the next quote)
  • Custom marker + mode rules (whitespace/char/set + optional max_len)

• Allows adding new rules and removing existing rules

• Generates a JSON representation of the current ruleset ({ "rules": [...] })

• Optionally shows the generated rules JSON in an “Advanced” panel

• Can copy the rules JSON to the clipboard

• Provides an input text area where a user pastes logs/code to redact

• Produces a redacted output text area showing the result

• Clears the output whenever rules or input change, so the user doesn’t mistake stale output for current output

• Runs redaction on demand via a “Run” button (and also does an initial run after the WASM loads)

• Uses a simple marker-based algorithm: finds each marker, replaces the following value up to a stop condition with [REDACTED]

• Shows basic status messages (loading/OK/edited/error) in the UI

Prerequisites

Tool	Purpose	Install (macOS)
Emscripten (em++)	Compile C++ → WebAssembly	brew install emscripten
Python 3	Local dev server	Included with macOS / brew install python

Build

Compile the redaction engine to WebAssembly:

em++ redact.cpp -O3 -I./vendor \
  -sWASM=1 -sMODULARIZE=1 -sEXPORT_ES6=1 -sENVIRONMENT=web \
  -sALLOW_MEMORY_GROWTH=1 --bind \
  -o public/redactor.mjs

This produces two files in public/: redactor.mjs (JS glue) and redactor.wasm.

Native CLI build (optional)

You can also build a standalone CLI binary for piping text through:

g++ -std=c++17 -O2 -I./vendor redact.cpp -o redact
echo 'Authorization: Bearer s3cret' | ./redact

Run locally

python3 -m http.server 8000 -d public

Then visit http://localhost:8000.

Frontend

Built with Lemonade.js — a lightweight reactive UI library with no build step or dependencies.