Paper 2021/248

Everlasting UC Commitments from Fully Malicious PUFs

Bernardo Magri
Giulio Malavolta
Dominique Schröder
Dominique Unruh

Everlasting security models the setting where hardness assumptions hold during the execution of a protocol but may get broken in the future. Due to the strength of this adversarial model, achieving any meaningful security guarantees for composable protocols is impossible without relying on hardware assumptions (Müller-Quade and Unruh, JoC'10). For this reason, a rich line of research has tried to leverage physical assumptions to construct well-known everlasting cryptographic primitives, such as commitment schemes. The only known everlastingly UC secure commitment scheme, due to Müller-Quade and Unruh (JoC'10), assumes honestly generated hardware tokens. The authors leave the possibility of constructing everlastingly UC secure commitments from malicious hardware tokens as an open problem. Goyal et al. (Crypto'10) constructs unconditionally UC-secure commitments and secure computation from malicious hardware tokens, with the caveat that the honest tokens must encapsulate other tokens. This extra restriction rules out interesting classes of hardware tokens, such as physically uncloneable functions (PUFs). In this work we present the first construction of an everlastingly UC-secure commitment scheme in the fully malicious token model without requiring honest token encapsulation. Our scheme assumes the existence of PUFs and is secure in the common reference string model. We also show that our results are tight by giving an impossibility proof for everlasting UC-secure computation from non-erasable tokens (such as PUFs), even with trusted setup.

Note: Same version accepted at the Journal of Cryptology

Available format(s)
Publication info
Published by the IACR in JOC 2022
Everlasting UC Commitment PUF Hardware assumption
Contact author(s)
bernardomagri21 @ gmail com
2022-06-07: revised
2021-03-02: received
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      author = {Bernardo Magri and Giulio Malavolta and Dominique Schröder and Dominique Unruh},
      title = {Everlasting {UC} Commitments from Fully Malicious {PUFs}},
      howpublished = {Cryptology ePrint Archive, Paper 2021/248},
      year = {2021},
      note = {\url{}},
      url = {}
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