Paper 2008/213

The Multireceiver Commitment Schemes

Shuhong Wang

Abstract

Existing commitment schemes were addressed under the classic two-party scenario. However, popularity of the secure multi-party computation in today's lush network communication is motivating us to adopt more sophisticate commitment schemes. In this paper, we study for the first time multireceiver commitment in unconditionally secure setting, i.e., one committer promises a group of verifiers a common secret value (in computational setting it is trivial). We extend the Rivest model for this purpose and present a provably secure generic construction using multireceiver authentication codes (without secrecy) as a building block. Two concrete schemes are proposed as its immediate implementations, which are almost as efficient as an optimal MRA-code. Furthermore, to affirmatively answer the open question of Pinto, Souto, Matos and Antunes, we present also a generic construction (for two-party case) using only an A-code with secrecy. Finally, we show the possibility of constructing multireceiver commitment schemes using other primitives such as verifiable secret sharing. We leave open problems and believe the work will open doors for more interesting research.