EMNLP 2024main22 citations

Extracting Prompts by Inverting LLM Outputs

Collin Zhang, John Xavier Morris, Vitaly Shmatikov

Abstract

We consider the problem of language model inversion: given outputs of a language model, we seek to extract the prompt that generated these outputs. We develop a new black-box method, output2prompt, that extracts prompts without access to the model’s logits and without adversarial or jailbreaking queries. Unlike previous methods, output2prompt only needs outputs of normal user queries. To improve memory efficiency, output2prompt employs a new sparse encoding techique. We measure the efficacy of output2prompt on a variety of user and system prompts and demonstrate zero-shot transferability across different LLMs.

BibTeX
@inproceedings{zhang-etal-2024-extracting,
    title = "Extracting Prompts by Inverting {LLM} Outputs",
    author = "Zhang, Collin  and
      Morris, John Xavier  and
      Shmatikov, Vitaly",
    editor = "Al-Onaizan, Yaser  and
      Bansal, Mohit  and
      Chen, Yun-Nung",
    booktitle = "Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing",
    month = nov,
    year = "2024",
    address = "Miami, Florida, USA",
    publisher = "Association for Computational Linguistics",
    url = "https://aclanthology.org/2024.emnlp-main.819/",
    doi = "10.18653/v1/2024.emnlp-main.819",
    pages = "14753--14777"
}
Extracting Prompts by Inverting LLM Outputs · EMNLP 2024