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 man-in-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.

Authors

• Rafael Pass
• Alon Rosen

Keywords

• Polynomials
• Circuits
• Communication standards
• Cryptographic protocols
• Contracts
• Usability
• Computer science
• Computer security
• Hash Function
• Number Of Executions
• Collision-resistant
• Upper Bound
• Stage 2
• Sequence Of Values
• Security Guarantees
• Security Parameter
• Proof Sketch
• Message Length
• Proof Of Property
• Signature Scheme
• Negligible Probability
• Probabilistic Polynomial Time
• Single Execution
• Zero-knowledge Proof