User profiling is a critical component of adaptive risk-based authentication, yet it raises significant privacy concerns, particularly when handling sensitive data. Profiling involves collecting and aggregating various user features, potentially creating quasi-identifiers that can reveal identities and compromise privacy. Even anonymized profiling methods remain vulnerable to re-identification attacks through these quasi-identifiers. This paper introduces a novel privacy-enhanced adaptive authentication protocol that leverages Oblivious Pseudorandom Functions (OPRF), anonymous tokens, and Differential Privacy (DP) to provide robust privacy guarantees. Our proposed approach dynamically adjusts authentication requirements based on real-time risk assessments, enhancing security while safeguarding user privacy. By integrating privacy considerations into the core of adaptive risk-based adaptive authentication, this approach addresses a gap often overlooked in traditional models. Advanced cryptographic techniques ensure confidentiality, integrity, and unlinkability of user data, while differential privacy mechanisms minimize the impact of individual data points on overall analysis. Formal security and privacy proofs demonstrate the protocol's resilience against various threats and its ability to provide strong privacy guarantees. Additionally, a comprehensive performance evaluation reveals that the computational and communication overheads are manageable, making the protocol practical for real-world deployment. By adhering to data protection regulations such as GDPR and CCPA, our protocol not only enhances security but also fosters user trust and compliance with legal standards.

翻译：用户画像是自适应风险认证的关键组成部分，但同时也引发了显著的隐私担忧，尤其是在处理敏感数据时。画像涉及收集和聚合多种用户特征，可能产生能够揭示身份并危及隐私的准标识符。即使是匿名化的画像方法，仍易受到通过这些准标识符进行的重识别攻击。本文提出了一种新颖的隐私增强自适应认证协议，该协议利用不经意伪随机函数（OPRF）、匿名令牌和差分隐私（DP）来提供强大的隐私保障。我们提出的方法基于实时风险评估动态调整认证要求，在增强安全性的同时保护用户隐私。通过将隐私考量融入自适应风险认证的核心，该方法弥补了传统模型中常被忽视的不足。先进的密码学技术确保了用户数据的机密性、完整性和不可链接性，而差分隐私机制则最小化了单个数据点对整体分析的影响。形式化的安全性与隐私性证明展示了该协议抵御各种威胁的能力及其提供强隐私保障的特性。此外，全面的性能评估表明，其计算与通信开销是可管理的，使得该协议在实际部署中具有可行性。通过遵循GDPR和CCPA等数据保护法规，我们的协议不仅增强了安全性，还促进了用户信任并符合法律标准。