On the Necessity of Collapsing for Post-Quantum and Quantum Commitments

Explore a prize-winning conference talk from TQC 2023 that delves into the fundamental aspects of post-quantum and quantum commitments, focusing on collapse binding and collapsing as essential strengthening mechanisms for computational binding and collision resistance in quantum settings. Learn why these concepts are crucial for transitioning classical security proofs to quantum environments through a detailed examination of a classical commit-and-open protocol. Discover how various "weak" binding notions like sum binding, CDMS binding, and unequivocality are equivalent to collapse binding in both post-quantum and quantum commitments. Understand the significant "win-win" result showing how non-collapse binding post-quantum computationally binding commitment schemes can be utilized to construct equivocal commitment schemes, leading to applications in one-shot signatures and other quantum primitives. Presented at the 18th Conference on the Theory of Quantum Computation, Communication and Cryptography at the University of Aveiro, this 32-minute talk demonstrates the theoretical foundations and practical implications of quantum information security.