# Stealthiness Evaluation on Harmful prompts (evaluated on 3 LLMs and 4 guard LLMs) Source: [Stealthiness Evaluation on Harmful prompts (evaluated on 3 LLMs and 4 guard LLMs)]() Collection index: [llms.txt]() Data updated: 2026-05-18T09:28:34.504Z Evaluation of model stealthiness using Perplexity metrics (PPL Mean/Std) when tested against harmful prompts, specifically involving comparisons between 3 standard LLMs and 4 guard LLMs. A research result applies to its stated dataset, split, metric and evaluation configuration. Compare like-for-like settings, preserve the metric's unit and direction, and distinguish paper-reported results from independent reproduction. The best result recorded here is not a claim of exhaustive, current global coverage. | Scope | Recorded value | | --- | --- | | Task | Stealthiness Evaluation | | Dataset (including any stated split) | Harmful prompts (evaluated on 3 LLMs and 4 guard LLMs) | | Metric | Mean Perplexity | | Unit | SCALAR | | Direction | Lower is better | | Results loaded | 10 of 10 | | Coverage | All results currently returned for this benchmark | Evaluation settings may differ between results. The original papers and recorded configurations are needed to establish comparability. A shared metric name alone does not establish an identical protocol. ## Metrics - [Mean Perplexity](): Lower is better; unit: SCALAR. - [PPL Std Dev](): Lower is better; unit: SCALAR. ## Recorded results | Method | Mean Perplexity | Result date | Report paper | | --- | --- | --- | --- | | ArtPrompt | 3.23 | Not recorded | 68fa751a1e209131cea65ca8 | | Ascii | 4.13 | Not recorded | 68fa751a1e209131cea65ca8 | | base64 | 10.46 | Not recorded | 68fa751a1e209131cea65ca8 | | Morse Cipher | 11.81 | Not recorded | 68fa751a1e209131cea65ca8 | | ReNeLLM | 15.56 | Not recorded | 68fa751a1e209131cea65ca8 | | Unicode | 42.19 | Not recorded | 68fa751a1e209131cea65ca8 | | UTF-8 | 42.19 | Not recorded | 68fa751a1e209131cea65ca8 | | Origin | 49.9 | Not recorded | 68fa751a1e209131cea65ca8 | | Caesar Cipher | 258.1 | Not recorded | 68fa751a1e209131cea65ca8 | | FlipAttack | 809.67 | Not recorded | 68fa751a1e209131cea65ca8 | ### ArtPrompt Mean Perplexity: 3.23. Result ID: 6a0adb6a47f34ce924f14ed5. [Reporting paper]() [Method origin paper]() Recorded evaluation configuration: Not recorded. This record does not assert independent reproduction. ### Ascii Mean Perplexity: 4.13. Result ID: 6a0adb6a47f34ce924f14ed3. [Reporting paper]() Recorded evaluation configuration: Not recorded. This record does not assert independent reproduction. ### base64 Mean Perplexity: 10.46. Result ID: 6a0adb6a47f34ce924f14ed4. [Reporting paper]() [Method origin paper]() Recorded evaluation configuration: Not recorded. This record does not assert independent reproduction. ### Morse Cipher Mean Perplexity: 11.81. Result ID: 6a0adb6a47f34ce924f14ed1. [Reporting paper]() Recorded evaluation configuration: Not recorded. This record does not assert independent reproduction. ### ReNeLLM Mean Perplexity: 15.56. Result ID: 6a0adb6a47f34ce924f14ed6. [Reporting paper]() [Method origin paper]() Recorded evaluation configuration: Not recorded. This record does not assert independent reproduction. ### Unicode Mean Perplexity: 42.19. Result ID: 6a0adb6a47f34ce924f14ed0. [Reporting paper]() Recorded evaluation configuration: Not recorded. This record does not assert independent reproduction. ### UTF-8 Mean Perplexity: 42.19. Result ID: 6a0adb6a47f34ce924f14ed2. [Reporting paper]() Recorded evaluation configuration: Not recorded. This record does not assert independent reproduction. ### Origin Mean Perplexity: 49.9. Result ID: 6a0adb6a47f34ce924f14ece. [Reporting paper]() Recorded evaluation configuration: Not recorded. This record does not assert independent reproduction. ### Caesar Cipher Mean Perplexity: 258.1. Result ID: 6a0adb6a47f34ce924f14ecf. [Reporting paper]() Recorded evaluation configuration: Not recorded. This record does not assert independent reproduction. ### FlipAttack Mean Perplexity: 809.67. Result ID: 6a0adb6a47f34ce924f14ed7. [Reporting paper]() [Method origin paper]() Recorded evaluation configuration: Not recorded. This record does not assert independent reproduction. Page 1 of 1. This is an index page, not the full collection.