Data loss prevention scanner

Design a data-loss-prevention (DLP) scanner for a large enterprise SaaS that inspects every outbound document, message, and API payload (200K events/s, files up to 1GB) for sensitive data, PII, PCI card numbers, source code, credentials, and blocks or quarantines policy violations in line with under 300ms added latency for interactive flows. Threat model: insiders exfiltrating data slowly, and accidental leaks via misconfigured shares. It must support content-aware policies (exact-data-match against a customer's own datasets) and minimize false positives that would break legitimate work. Cover classification pipeline, the exact-match index, and how you handle large files and encryption.