Paper 2013/108
Unconditionally Secure and Universally Composable Commitments from Physical Assumptions
Ivan Damgard and Alessandra Scafuro
Abstract
We present a constant-round unconditional black-box compiler, that transforms any ideal straight- line extractable commitment scheme, into an extractable and equivocal commitment scheme, therefore yielding to UC-security [Can01]. We exemplify the usefulness of our compiler providing two (constant- round) instantiations of ideal straight-line extractable commitment using (malicious) PUFs [OSVW13] and stateless tamper-proof hardware tokens [Kat07]. This allows us to achieve the first unconditionally UC-secure commitment with malicious PUFs and the first unconditionally UC-secure commitment with stateless tokens. Our constructions are secure for adversaries creating arbitrarily malicious stateful PUFs/tokens. Previous results with malicious PUFs used either computational assumptions to achieve UC-secure commitments or were unconditionally secure but only in the indistinguishability sense [OSVW13]. Similarly, with stateless tokens, UC-secure commitments are known only under computational assumptions [CGS08, GIS+10, CKS+11], while the (not UC) unconditional commitment scheme of [GIMS10] is secure only in a weaker model in which the adversary is not allowed to create stateful tokens. Besides allowing us to prove feasibility of unconditional UC-security with (malicious) PUFs and stateless tokens, our compiler can be instantiated with any ideal straight-line extractable commitment scheme, thus allowing the use of various setup assumptions which may better fit the application or the technology available.
Metadata
- Available format(s)
- Category
- Foundations
- Publication info
- Published elsewhere. Unknown where it was published
- Keywords
- UChardware assumptionsunconditional securitycommitment scheme
- Contact author(s)
- alescafu @ gmail com
- History
- 2015-03-03: last of 3 revisions
- 2013-02-27: received
- See all versions
- Short URL
- https://ia.cr/2013/108
- License
-
CC BY