Zero-Trust Tool Sanitizes API Keys and PII Locally Before Sending Prompts to LLMs

Developers using AI coding assistants such as Cursor, Claude Desktop, and ChatGPT frequently risk exposing sensitive data like API keys, database credentials, and customer information within their prompts. Traditional Data Loss Prevention solutions address this by routing traffic through remote cloud proxies, but this introduces latency, third-party data-sharing obligations under GDPR and HIPAA, and centralized log vulnerabilities. A proposed approach called Zero-Trust Data Sanitization (ZTDS) instead performs all sensitive-data scrubbing entirely within the client's local memory before any network transmission occurs. An open-source tool called PrivacyScrubber implements this method, tokenizing credentials and personally identifiable information in under 1.5 milliseconds and rehydrating original values locally after the LLM responds. The project is available as an MCP server, a Chrome extension, and a browser-based web app, with its technical foundation published on Zenodo.