arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2312.04469cs.LGcs.CLcs.CR
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关于语言模型水印可学习性的研究

On the Learnability of Watermarks for Language Models

Stanford University(斯坦福大学)

Chenchen Gu, Xiang Lisa Li, Percy Liang, Tatsunori Hashimoto

AI总结:

本文研究语言模型能否直接学习生成带水印文本,提出水印蒸馏方法训练学生模型模仿基于解码的水印教师模型,实验证明模型可学会生成高可检测性的水印文本,同时揭示了微调导致水印能力丧失和低失真水印样本复杂度高等局限。

摘要:

语言模型输出的水印处理能够对模型生成的文本进行统计检测,从而有助于减少语言模型带来的危害和滥用。现有的水印策略通过改变现有语言模型的解码器来运作。在本文中,我们探讨语言模型是否可以直接学习生成带水印的文本,这将对水印在现实世界中的部署产生重要影响。首先,学习得到的水印可用于构建自然生成带水印文本的开放模型,从而在用户可以控制解码过程的情况下,为开放模型实现水印功能。其次,如果水印被用于确定生成文本的来源,攻击者可以通过伪造受害者模型的水印并生成具有破坏性的带水印文本来损害其声誉。为了研究水印的可学习性,我们提出了水印蒸馏方法,该方法训练一个学生模型,使其表现得像使用基于解码的水印的教师模型。我们在三种基于解码的水印策略和各种超参数设置上测试了我们的方法,发现模型能够学习生成具有高可检测性的带水印文本。我们还发现了可学习性的局限性,包括在普通文本上进行微调后水印能力会丧失,以及在学习低失真水印时样本复杂度较高。

英文摘要:

Watermarking of language model outputs enables statistical detection of model-generated text, which can mitigate harms and misuses of language models. Existing watermarking strategies operate by altering the decoder of an existing language model. In this paper, we ask whether language models can directly learn to generate watermarked text, which would have significant implications for the real-world deployment of watermarks. First, learned watermarks could be used to build open models that naturally generate watermarked text, enabling watermarking for open models, where users can control the decoding procedure. Second, if watermarking is used to determine the provenance of generated text, an adversary can hurt the reputation of a victim model by spoofing its watermark and generating damaging watermarked text. To investigate the learnability of watermarks, we propose watermark distillation, which trains a student model to behave like a teacher model that uses decoding-based watermarking. We test our approach on three decoding-based watermarking strategies and various hyperparameter settings, finding that models can learn to generate watermarked text with high detectability. We also find limitations to learnability, including the loss of watermarking capabilities under fine-tuning on normal text and high sample complexity when learning low-distortion watermarks.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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