Concurrent Non-Malleable Commitments

We present a non-malleable commitment scheme that retains its security properties even when concurrently executed a polynomial number of times. That is, a manin-the-middle adversary who is simultaneously participating in multiple concurrent commitment phases of our scheme, both as a sender and as a receiver, cannot make the values he commits to depend on the values he receives commitments to. Our result is achieved without assuming an a-priori bound on the number of executions and without relying on any set-up assumptions. Our construction relies on the existence of standard collision resistant hash functions and only requires a constant number of communication rounds.

• Type: Conference
• Year: 2005
• Where: FOCS
• Authors: Rafael Pass, Alon Rosen
• Keywords: Concurrent Commitment Phases, FOCS 2005, Non-malleable Commitment Scheme, Polynomial Number, Theoretical Computer Science