Bit Commitment from Non-Signaling Correlations

TL;DR

This paper demonstrates that non-trivial two-party systems without message transmission can be used to achieve unconditionally secure bit commitment, expanding the understanding of cryptographic primitives based on non-signaling correlations.

Contribution

It introduces a new approach to secure bit commitment using non-signaling correlations, showing their sufficiency beyond distributed randomness.

Findings

Non-trivial two-party systems enable secure bit commitment.

Secure bit commitment is possible without message transmission.

Non-signaling correlations are a sufficient primitive for cryptography.

Abstract

Central cryptographic functionalities such as encryption, authentication, or secure two-party computation cannot be realized in an information-theoretically secure way from scratch. This serves as a motivation to study what (possibly weak) primitives they can be based on. We consider as such starting points general two-party input-output systems that do not allow for message transmission, and show that they can be used for realizing unconditionally secure bit commitment as soon as they are non-trivial, i.e., cannot be securely realized from distributed randomness only.