With the recent explosive growth of interest and investment in virtual reality (VR) and the so-called "metaverse," public attention has rightly shifted toward the unique security and privacy threats that these platforms may pose. While it has long been known that people reveal information about themselves via their motion, the extent to which this makes an individual globally identifiable within virtual reality has not yet been widely understood. In this study, we show that a large number of real VR users (N=55,541) can be uniquely and reliably identified across multiple sessions using just their head and hand motion relative to virtual objects. After training a classification model on 5 minutes of data per person, a user can be uniquely identified amongst the entire pool of 50,000+ with 94.33% accuracy from 100 seconds of motion, and with 73.20% accuracy from just 10 seconds of motion. This work is the first to truly demonstrate the extent to which biomechanics may serve as a unique identifier in VR, on par with widely used biometrics such as facial or fingerprint recognition.

翻译：随着虚拟现实（VR）及所谓"元宇宙"领域的兴趣与投资近期激增，公众关注焦点正合理转向这些平台可能带来的独特安全与隐私威胁。虽然人们早已认识到个体通过自身动作会泄露个人信息，但这种动作特征在虚拟现实环境中对个人全球识别的程度尚未被广泛认知。本研究证明，大量真实VR用户（N=55,541）可基于其相对虚拟物体的头部与手部动作，在多次会话中被唯一且可靠地识别。在针对每位用户训练5分钟数据构建分类模型后，通过100秒动作数据即可在超过5万名用户池中以94.33%的准确率唯一识别该用户，仅凭10秒动作数据亦能达到73.20%的准确率。本研究首次真正揭示了生物力学特征在VR中作为唯一身份识别手段的潜力——其识别能力已可媲美人脸识别或指纹识别等广泛使用的生物特征技术。