Concurrently-Secure Blind Signatures without Random Oracles or Setup Assumptions

Carmit Hazay, Jonathan Katz, Chiu-Yuen Koo and Yehuda Lindell


We show a new protocol for blind signatures in which security is preserved even under arbitrarily-many concurrent executions. The protocol can be based on standard cryptographic assumptions and is the first to be proven secure in a concurrent setting (under any assumptions) without random oracles or a trusted setup assumption such as a common reference string. Along the way, we also introduce new definitions of security for blind signature schemes.

Postscript, gzipped Postscript.

Back Home