Trusted Platform Module (TPM) 2.0 devices provide efficient hardware-based cryptographic security through tamper-resistant key storage and computation, making them ideal building blocks for multi-party signature schemes in distributed systems. However, existing TPM-based multi-signature constructions suffer from a fundamental limitation, they require interactive protocols where all participants must coordinate during the commitment phase, before any signature can be computed. This interactive requirement creates several critical problems, such as synchronization bottlenecks, quadratic communication complexity, and aborted protocols as a result of participant failure. These limitations become particularly heightened for applications that require cross-device cryptographic operations. This paper presents PiTPM, an Aggregator Framework built upon Schnorr's digital signature. Our protocol eliminates the interactive requirement using a hybrid trust architecture. The proposed framework uses pre-shared randomness seeds stored securely in an Aggregator, enabling deterministic computation of global commitments without inter-participant communication. The resulting signatures of the proposed framework are of constant size regardless of signer count. Our experimental results show a possible paradigm shift in TPM-based cryptographic system design, demonstrating that hybrid trust architectures can achieve significant performance improvements while maintaining rigorous security guarantees. We provide a comprehensive formal security analysis proving EU-CMA security under the discrete logarithm assumption in the random oracle model.

翻译：可信平台模块（TPM）2.0设备通过防篡改的密钥存储与计算提供基于硬件的高效密码学安全保障，使其成为分布式系统中多方签名方案的理想构建模块。然而，现有基于TPM的多签名方案存在一个根本性局限：它们需要交互式协议，要求所有参与方在计算任何签名前必须于承诺阶段进行协同。这种交互需求引发了若干关键问题，例如同步瓶颈、二次通信复杂度以及因参与方故障导致的协议中止。对于需要跨设备密码学操作的应用场景，这些限制尤为突出。本文提出PiTPM——一个基于Schnorr数字签名的聚合器框架。该协议通过混合信任架构消除了交互需求。所提框架利用安全存储于聚合器中的预共享随机数种子，使得无需参与者间通信即可确定性计算全局承诺。无论签名者数量如何，所生成签名的尺寸保持恒定。实验结果表明，基于TPM的密码系统设计可能出现范式转变：混合信任架构在保持严格安全保证的同时，能够实现显著的性能提升。我们提供了完备的形式化安全分析，在随机预言机模型下基于离散对数假设证明了其具备EU-CMA安全性。