Universally composable zero-knowledge arguments and commitments from signature cards

Year, pages: 2007, 93 - 103

In the Universal Composability framework many cryptographic tasks cannot be built from scratch. Additional ``helping'' functionalities are need-ed to realise zero-knowledge or bit commitment. However, all the additional functionalities presented in the literature so far have to be specially designed as a ``helping'' functionality and cannot directly serve any other purpose without endangering the universal composability. In this work, we introduce the concept of {em catalysts}. Informally a functionality~$mathcal{C}$ is a {em catalyst} for a functionality~$mathcal F$ if~$mathcal {F}$ can be implemented given the primitive~$mathcal {C}$ and the functionality~$mathcal {C}$ can still directly be used by other applications without any additional precautions. We prove that catalysts exist for zero-knowledge and bit commitment. And, what is more, we show that a signature card, which is in accordance with the German law [ extit{{G}esetz {"u}ber {R}ahmenbedingungen f{"u}r elektronische {S}ignaturen}. Bundesgesetzblatt I 2001, 876, May 2001. Online available at url{http://bundesrecht.juris.de/bundesrecht/sigg_2001/inhalt.html}] can be used as such a catalyst.

Hofheinz, D., Müller-Quade, J., Unruh, D. 2007. Universally composable zero-knowledge arguments and commitments from signature cards. In Tatra Mountains Mathematical Publications, vol. 37, no.3, pp. 93-103. 1210-3195.

Hofheinz, D., Müller-Quade, J., Unruh, D. (2007). Universally composable zero-knowledge arguments and commitments from signature cards. Tatra Mountains Mathematical Publications, 37(3), 93-103. 1210-3195.