International Association for Cryptologic Research

International Association
for Cryptologic Research


Reusing Tamper-Proof Hardware in UC-Secure Protocols

Jeremias Mechler
Jörn Müller-Quade
Tobias Nilges
DOI: 10.1007/978-3-319-76578-5_16
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Conference: PKC 2018
Abstract: Universally composable protocols provide security even in highly complex environments like the Internet. Without setup assumptions, however, UC-secure realizations of cryptographic tasks are impossible. Tamper-proof hardware tokens, e.g. smart cards and USB tokens, can be used for this purpose. Apart from the fact that they are widely available, they are also cheap to manufacture and well understood.Currently considered protocols, however, suffer from two major drawbacks that impede their practical realization:The functionality of the tokens is protocol-specific, i.e. each protocol requires a token functionality tailored to its need.Different protocols cannot reuse the same token even if they require the same functionality from the token, because this would render the protocols insecure in current models of tamper-proof hardware. In this paper we address these problems. First and foremost, we propose formalizations of tamper-proof hardware as an untrusted and global setup assumption. Modeling the token as a global setup naturally allows to reuse the tokens for arbitrary protocols. Concerning a versatile token functionality we choose a simple signature functionality, i.e. the tokens can be instantiated with currently available signature cards. Based on this we present solutions for a large class of cryptographic tasks.
  title={Reusing Tamper-Proof Hardware in UC-Secure Protocols},
  booktitle={Public-Key Cryptography – PKC 2018},
  series={Public-Key Cryptography – PKC 2018},
  author={Jeremias Mechler and Jörn Müller-Quade and Tobias Nilges},