Evasion Technique Decoders — 7-stage normalization pipeline

2026-03-23

What We Built

7-stage evasion decoder pipeline that normalizes obfuscated content before guardrail checks:

1. Invisible character stripping (zero-width, directional overrides)
2. Whitespace normalization (Unicode spaces, collapse runs)
3. Unicode homoglyph normalization (Cyrillic/Greek → ASCII)
4. Leetspeak normalization (1337 → readable)
5. ROT13 detection and decode
6. Base64 detection and decode
7. Cross-lingual injection detection

Performance: <10ms for full pipeline. Per-decoder enable/disable via config.

Lockstep Checklist

• [x] API: Decoder pipeline module
• [x] Tests: 18 tests for all decoders + pipeline
• [x] Docs: Ship log