## Cryptology ePrint Archive: Report 2010/339

A Certifying Compiler for Zero-Knowledge Proofs of Knowledge Based on $\Sigma$-Protocols

Jose Bacelar Almeida and Endre Bangerter and Manuel Barbosa and Stephan Krenn and Ahmad-Reza Sadeghi and Thomas Schneider

Abstract: Zero-knowledge proofs of knowledge (ZK-PoK) are important building blocks for numerous cryptographic applications. Although ZK-PoK have very useful properties, their real world deployment is typically hindered by their significant complexity compared to other (non-interactive) crypto primitives. Moreover, their design and implementation is time-consuming and error-prone.

We contribute to overcoming these challenges as follows: We present a comprehensive specification language and a certifying compiler for ZK-PoK protocols based on $\Sigma$-protocols and composition techniques known in literature. The compiler allows the fully automatic translation of an abstract description of a proof goal into an executable implementation. Moreover, the compiler overcomes various restrictions of previous approaches, e.g., it supports the important class of exponentiation homomorphisms with hidden-order co-domain, needed for privacy-preserving applications such as idemix. Finally, our compiler is certifying, in the sense that it automatically produces a formal proof of security (soundness) of the compiled protocol (currently covering special homomorphisms) using the Isabelle/HOL theorem prover.

Category / Keywords: implementation / Zero-Knowledge, Protocol Compiler, Formal Verification

Publication Info: An extended abstract of this work will be presented at ESORICS 2010

Date: received 10 Jun 2010, last revised 4 Aug 2010

Contact author: stephan krenn at bfh ch; thomas schneider@trust rub de

Available format(s): PDF | BibTeX Citation

Short URL: ia.cr/2010/339

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