Variable Bias Coin Tossing

Abstract

Alice is a charismatic quantum cryptographer who believes her parties are unmissable; Bob is a (relatively) glamorous string theorist who believes he is an indispensable guest. To prevent possibly traumatic collisions of self-perception and reality, their social code requires that decisions about invitation or acceptance be made via a cryptographically secure variable bias coin toss (VBCT). This generates a shared random bit by the toss of a coin whose bias is secretly chosen, within a stipulated range, by one of the parties; the other party learns only the random bit. Thus one party can secretly influence the outcome, while both can save face by blaming any negative decisions on bad luck. We describe here some cryptographic VBCT protocols whose security is guaranteed by quantum theory and the impossibility of superluminal signalling, setting our results in the context of a general discussion of secure two-party computation. We also briefly discuss other cryptographic applications of VBCT.

14 pages, minor corrections

References in corpus (13)

• Simple Proof of Security of the BB84 Quantum Key Distribution Protocol
• Unconditional Security Of Quantum Key Distribution Over Arbitrarily Long Distances
• No Signalling and Quantum Key Distribution
• Unconditionally secure quantum bit commitment is impossible
• Insecurity of Quantum Secure Computations
• Degrees of concealment and bindingness in quantum bit commitment protocols
• Unconditionally Secure Bit Commitment
• Superselection rules and quantum protocols
• Why Quantum Bit Commitment And Ideal Quantum Coin Tossing Are Impossible
• Cheat Sensitive Quantum Bit Commitment
• A quantum protocol for cheat-sensitive weak coin flipping
• Coin Tossing is Strictly Weaker Than Bit Commitment
• A large family of quantum weak coin-flipping protocols

Cited by in corpus (20)

• Unconditionally Secure Bit Commitment by Transmitting Measurement Outcomes
• Quantum Tagging: Authenticating Location via Quantum Information and Relativistic Signalling Constraints
• The Impossibility Of Secure Two-Party Classical Computation
• Quantum Tasks in Minkowski Space
• Quantum Tagging for Tags Containing Secret Classical Data
• Device-Independent Relativistic Quantum Bit Commitment
• Spacetime-constrained oblivious transfer
• Location-Oblivious Data Transfer with Flying Entangled Qudits
• Practical and unconditionally secure spacetime-constrained oblivious transfer
• Multiphoton and side-channel attacks in mistrustful quantum cryptography
• A general framework for cyclic and fine-tuned causal models and their compatibility with space-time
• Deterministic Relativistic Quantum Bit Commitment
• Impossibility of superluminal signalling in Minkowski space-time does not rule out causal loops
• Why Classical Certification is Impossible in a Quantum World
• Quantum non-locality, causality and mistrustful cryptography
• Unconditionally secure relativistic multi-party biased coin flipping and die rolling
• Quantum Privacy-Preserving Perceptron
• Secure and Robust Transmission and Verification of Unknown Quantum States in Minkowski Space
• Quantum oblivious transfer: a short review
• The standard no-signalling constraints in Bell scenarios are neither sufficient nor necessary for preventing superluminal signalling with general interventions