Cited by 164Authorship Attribution and ProfilingSpam and Phishing DetectionDigital Media Forensic Detection

Paraphrasing evades detectors of AI-generated text, but retrieval is an effective defense

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Krishna, Kalpesh, Song, Yixiao, Karpinska, Marzena, Wieting, John, Iyyer, Mohit·2023·Advances in Neural Information Processing Systems 36

Abstract

The rise in malicious usage of large language models, such as fake content creation and academic plagiarism, has motivated the development of approaches that identify AI-generated text, including those based on watermarking or outlier detection. However, the robustness of these detection algorithms to paraphrases of AI-generated text remains unclear. To stress test these detectors, we build a 11B parameter paraphrase generation model (DIPPER) that can paraphrase paragraphs, condition on surrounding context, and control lexical diversity and content reordering. Using DIPPER to paraphrase text generated by three large language models (including GPT3.5-davinci-003) successfully evades several detectors, including watermarking, GPTZero, DetectGPT, and OpenAI's text classifier. For example, DIPPER drops detection accuracy of DetectGPT from 70.3% to 4.6% (at a constant false positive rate of 1%), without appreciably modifying the input semantics. To increase the robustness of AI-generated text detection to paraphrase attacks, we introduce a simple defense that relies on retrieving semantically-similar generations and must be maintained by a language model API provider. Given a candidate text, our algorithm searches a database of sequences previously generated by the API, looking for sequences that match the candidate text within a certain threshold. We empirically verify our defense using a database of 15M generations from a fine-tuned T5-XXL model and find that it can detect 80% to 97% of paraphrased generations across different settings while only classifying 1% of human-written sequences as AI-generated. We open-source our models, code and data.

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  • Simple paraphrasing leads to an average relative drop in T@1%F of 30.27%.

    “On average, simple paraphrasing leads to a 30.27% relative drop in T@1%F.”

    From Adversarial Paraphrasing: A Universal Attack for Humanizing AI-Generated Text (2025) · cites this paper as [15]

    Section 4.1 defines detection accuracy at a 1% false-positive rate, and Section 4.3 reports that paraphrasing significantly lowers it. But the paper reports results for DIPPER paraphrasing and does not state an average relative drop of 30.27% or identify that figure with simple paraphrasing. (LLM, conf=0.87)

    Experimental — accuracy not yet measured
  • Rather than promoting ethical academic behavior, AI detection tools often encourage strategic avoidance tactics, such as paraphrasing services or altering sentence structures to bypass detection.

    “Rather than promoting ethical academic behavior, AI detection tools often encourage strategic avoidance tactics, such as paraphrasing services or altering sentence structures to bypass detection [15,23].”

    From Evaluating the Effectiveness and Ethical Implications of AI Detection Tools in Higher Education (2025) · cites this paper as [23]

    Section 4.4 describes paraphrasing as a tactic for evading AI-text detectors, and the Ethical Considerations section notes that students could use such attacks. The paper does not establish that detection tools often encourage avoidance tactics or that they fail to promote ethical academic behavior. No page numbers were supplied in our copy. (LLM, conf=0.86)

    Experimental — accuracy not yet measured
  • This undermines the goal of meaningful learning, as students are more focused on passing algorithmic checks than developing deeper critical thinking and reflective writing skills.

    “This undermines the goal of meaningful learning, as students are more focused on “passing” algorithmic checks than developing deeper critical thinking and reflective writing skills [23].”

    From Evaluating the Effectiveness and Ethical Implications of AI Detection Tools in Higher Education (2025) · cites this paper as [23]

    The Ethical Considerations section mentions college students as potential users of ChatGPT in essays who might wish to evade AI-text detectors. It does not establish that students generally focus more on passing checks than on critical thinking or reflective writing, or that detection undermines meaningful learning. (LLM, conf=0.77)

    Experimental — accuracy not yet measured
  • Sadasivan et al. [28] and Krishna et al. [15] demonstrated how AI-generated text can be paraphrased by another AI model to evade detection by existing AI detectors.

    “Sadasivan et al. [28] and Krishna et al. [15] demonstrated how AI-generated text can be paraphrased by another AI model to evade detection by the existing AI detectors.”
  • Krishna et al. [15] proposed DIPPER, a powerful T5-based paraphrasing model that significantly enhances the effectiveness of such attacks.

    “Krishna et al. [15] proposed DIPPER, a powerful T5-based [24] paraphrasing model that significantly enhances the effectiveness of such attacks.”

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Cited by

Sorted by citations

Authors
Krishna, K., Song, Y., Karpinska, M., Wieting, J., & Iyyer, M.
Venue
Advances in Neural Information Processing Systems 36
Published
2023
Pages
27469-27500
ISSN
1049-5258 (ISSN-L)
OpenAlex
W7133209433
Cited by
150
References
0
Citations by year
2026: 55 · 2025: 33 · 2024: 36 · 2023: 25 · 2021: 1
FWCI
26.40
Type
conference paper
Language
en
Open access
Locations
  • neural information processing systems (publishedVersion)
  • arXiv (Cornell University) (submittedVersion)
  • arXiv (Cornell University)
Topics
  • Physical Sciences › Computer Science › Artificial Intelligence › Authorship Attribution and Profiling
  • Physical Sciences › Computer Science › Information Systems › Spam and Phishing Detection
  • Physical Sciences › Computer Science › Computer Vision and Pattern Recognition › Digital Media Forensic Detection
Keywords
paraphrase, AI-generated text detection, text retrieval, large language models

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