T2-AT-017MEDIUM

Compression Techniques

T2 · Semantic & Linguistic Evasion →
Risk score170
RatingMedium
Procedures10
Severity
Mechanism

Compresses harmful requests using text-speak, vowel removal, consonant skeletons, first-letter acronyms, and shorthand. SMS-era compression ("hw 2 mk bm") exploits the model's training on internet text where such compression is common. The model decodes from context; the classifier sees unrecognizable tokens.

Detection
  • Text expansion/decompression before classification
  • Detect abnormally high consonant-to-vowel ratios
Mitigation
Text expansion heuristicsMEDIUM
Semantic classifiers (robust to compression)HIGH
Chaining

Chains with T2-AT-003 (Encoding) — compression is a form of encoding. Nested compression+encoding creates compound evasion.

Framework mapping
OWASP LLMLLM01
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