Implicit Zero-Knowledge Arguments and Applications to the Malicious Setting

Fabrice Benhamouda (1, 2, 3) , Geoffroy Couteau (1, 2, 3) , David Pointcheval (1, 2, 3) , Hoeteck Wee (1, 2, 3)

1 CASCADE - Construction and Analysis of Systems for Confidentiality and Authenticity of Data and Entities
2 LIENS - Laboratoire d'informatique de l'école normale supérieure
3 ENS-PSL - École normale supérieure - Paris

We introduce \emph{implicit zero-knowledge} arguments (iZK) and simulation-sound variants thereof (SSiZK); these are lightweight alternatives to zero-knowledge arguments for enforcing semi-honest behavior. Our main technical contribution is a construction of efficient two-flow iZK and SSiZK protocols for a large class of languages under the (plain) DDH assumption in cyclic groups in the common reference string model. As an application of iZK, we improve upon the round-efficiency of existing protocols for securely computing inner product under the DDH assumption. This new protocol in turn provides privacy-preserving biometric authentication with lower latency.

Domaines: Cryptographie et sécurité [cs.CR]

Fabrice Benhamouda, Geoffroy Couteau, David Pointcheval, Hoeteck Wee. Implicit Zero-Knowledge Arguments and Applications to the Malicious Setting. [Technical Report] Cryptology ePrint Archive: Report 2015/246, IACR. 2015. ⟨hal-01139320⟩