Universally composable blind signature functionality
Blind signatures play a critical role in digital cash systems. In this paper, we investigate the blind signature functionality in the framework of universally composable (UC) security - the strongest security guarantees up to now for cryptographic protocols over the Internet. We present the universally composable blind signature functionality, F-BSIG. Our approach is based on a new UC signature functionality F-MSIG, which is a modified version of the original signature functionality F-SIG presented by Canetti. We also prove that F-MSIG and F-SIG are actually equivalent with respect to non-adaptive adversaries. Our result is of both theoretical and practical consequence to future research studies and practical implementations of digital cash systems with universally composable security.
blind signatures universally composable security digial cash