TY - GEN
T1 - A framework for practical universally composable zero-knowledge protocols
AU - Camenisch, Jan
AU - Krenn, Stephan
AU - Shoup, Victor
PY - 2011
Y1 - 2011
N2 - Zero-knowledge proofs of knowledge (ZK-PoK) for discrete logarithms and related problems are indispensable for practical cryptographic protocols. Recently, Camenisch, Kiayias, and Yung provided a specification language (the CKY-language) for such protocols which allows for a modular design and protocol analysis: for every zero-knowledge proof specified in this language, protocol designers are ensured that there exists an efficient protocol which indeed proves the specified statement. However, the protocols resulting from their compilation techniques only satisfy the classical notion of ZK-PoK, which is not retained are when they used as building blocks for higher-level applications or composed with other protocols. This problem can be tackled by moving to the Universal Composability (UC) framework, which guarantees retention of security when composing protocols in arbitrary ways. While there exist generic transformations from ∑-protocols to UC-secure protocols, these transformation are often too inefficient for practice. In this paper we introduce a specification language akin to the CKY-language and a compiler such that the resulting protocols are UC-secure and efficient. To this end, we propose an extension of the UC-framework addressing the issue that UC-secure zero-knowledge proofs are by definition proofs of knowledge, and state a special composition theorem which allows one to use the weaker - but more efficient and often sufficient - notion of proofs of membership in the UC-framework. We believe that our contributions enable the design of practically efficient protocols that are UC-secure and thus themselves can be used as building blocks.
AB - Zero-knowledge proofs of knowledge (ZK-PoK) for discrete logarithms and related problems are indispensable for practical cryptographic protocols. Recently, Camenisch, Kiayias, and Yung provided a specification language (the CKY-language) for such protocols which allows for a modular design and protocol analysis: for every zero-knowledge proof specified in this language, protocol designers are ensured that there exists an efficient protocol which indeed proves the specified statement. However, the protocols resulting from their compilation techniques only satisfy the classical notion of ZK-PoK, which is not retained are when they used as building blocks for higher-level applications or composed with other protocols. This problem can be tackled by moving to the Universal Composability (UC) framework, which guarantees retention of security when composing protocols in arbitrary ways. While there exist generic transformations from ∑-protocols to UC-secure protocols, these transformation are often too inefficient for practice. In this paper we introduce a specification language akin to the CKY-language and a compiler such that the resulting protocols are UC-secure and efficient. To this end, we propose an extension of the UC-framework addressing the issue that UC-secure zero-knowledge proofs are by definition proofs of knowledge, and state a special composition theorem which allows one to use the weaker - but more efficient and often sufficient - notion of proofs of membership in the UC-framework. We believe that our contributions enable the design of practically efficient protocols that are UC-secure and thus themselves can be used as building blocks.
KW - Protocol Design
KW - UC-Framework
KW - Zero-Knowledge Proof
UR - http://www.scopus.com/inward/record.url?scp=82955184601&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=82955184601&partnerID=8YFLogxK
U2 - 10.1007/978-3-642-25385-0_24
DO - 10.1007/978-3-642-25385-0_24
M3 - Conference contribution
AN - SCOPUS:82955184601
SN - 9783642253843
T3 - Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
SP - 449
EP - 467
BT - Advances in Cryptology, ASIACRYPT 2011 - 17th International Conference on the Theory and Application of Cryptology and Information Security, Proceedings
T2 - 17th International Conference on the Theory and Application of Cryptology and Information Security, ASIACRYPT 2011
Y2 - 4 December 2011 through 8 December 2011
ER -