PiTPM: Partially Interactive Signatures for Multi-Device TPM Operations

2026-02-10

AI Summary

Existing TPM-based multisignature schemes require real-time interaction among participants during the commitment phase, resulting in high communication overhead, synchronization bottlenecks, and vulnerability to protocol failure upon device faults—issues particularly acute in cross-device settings. This work proposes PiTPM, the first framework for TPM-based multisignatures that eliminates inter-participant interaction by leveraging an aggregator to securely store a pre-shared random seed. Combining Schnorr multisignatures with a hybrid trust architecture, PiTPM enables deterministic generation of a global commitment without any communication among signers. The scheme produces constant-size signatures independent of the number of participants and is proven secure under EU-CMA in the random oracle model assuming the hardness of the discrete logarithm problem. Experimental evaluation demonstrates that PiTPM significantly improves both efficiency and robustness.

Technology Category

• Multiagent Systems: Mechanism Design
• Data Mining & Knowledge Management: Representing, Reasoning, and Using Provenance, Trust
• Computer Vision: Multi-modal Vision

Application Category

• Security and Privacy: Large-scale security measurements
• Responsible Web: Data and user privacy-enhancing technologies for the Web
• User Modeling, Personalization and Recommendation: Attacks and countermeasures in recommendation systems

Abstract

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.

Problem

• multi-signature
• Trusted Platform Module
• interactive protocol
• cross-device cryptography
• commitment phase

Innovation

• Partially Interactive Signatures
• Hybrid Trust Architecture
• TPM 2.0
• Multi-Device Cryptography
• Constant-Size Signatures