Abstract
Coin-flipping is a cryptographic task in which two physically separated, mistrustful parties wish to generate a fair coin-flip by communicating with each other. Chailloux and Kerenidis (2009) designed quantum protocols that guarantee coin-flips with near optimal bias away from uniform, even when one party deviates arbitrarily from the protocol. The probability of any outcome in these protocols is provably at most \(\tfrac{1}{\sqrt{2}} + \delta \) for any given \(\delta > 0\). However, no explicit description of these protocols is known; in fact, the smallest bias achieved by known explicit protocols is \(1/4\) (Ambainis 2001). We take a computational optimization approach, based mostly on convex optimization, to the search for simple and explicit quantum strong coin-flipping protocols. We present a search algorithm to identify protocols with low bias within a natural class, protocols based on bit-commitment (Nayak and Shor in Phys Rev A 67(1):012304, 2003). The techniques we develop enable a computational search for protocols given by a mesh over the corresponding parameter space. We conduct searches for four-round and six-round protocols with bias below \(0.2499\) each of varying dimension which include the best known explicit protocol (with bias \(1/4\)). After checking over \(10^{16}\) protocols, a task which would be infeasible using semidefinite programming alone, we conjecture that the smallest achievable bias within the family of protocols we consider is \(1/4\).
Similar content being viewed by others
Explore related subjects
Discover the latest articles, news and stories from top researchers in related subjects.References
Aharonov, D., Chailloux, A., Ganz, M., Kerenidis, I., Magnin, L.: A simpler proof of existence of quantum weak coin flipping with arbitrarily small bias (2013). Manuscript
Aharonov, D., Ta-Shma, A., Vazirani, U., Yao, A.C.C.: Quantum bit escrow. In: Proceedings of 32nd Annual ACM Symposium on the Theory of Computing, 705–714. ACM (2000). doi:10.1145/335305.335404
Ambainis, A.: A new protocol and lower bounds for quantum coin flipping. In: Proceedings of 33rd Annual ACM Symposium on the Theory of Computing, 134–142. ACM (2001). doi:10.1109/FOCS.2004.13
Bennett, C., Brassard, G.: Quantum cryptography: public key distribution and coin tossing. In: Proceedings of the IEEE International Conference on Computers, Systems, and Signal Processing, 175–179. IEEE Computer Society (1984)
Bernstein, E., Vazirani, U.V.: Quantum complexity theory. SIAM J. Comput. 26(5), 1411–1473 (1997)
Blum, M.: Coin flipping by telephone. In: Gersho, A. (ed.) Advances in Cryptology: A Report on CRYPTO 81, CRYPTO 81, IEEE Workshop on Communications Security, Santa Barbara, California, USA, August 24–26, 1981, pp. 11–15. U. C. Santa Barbara, Department of Electrical and Computer Engineering, ECE Report No. 82–04, 1982 (1981)
Chailloux, A., Kerenidis, I.: Optimal quantum strong coin flipping. In: Proceedings of 50th IEEE Symposium on Foundations of Computer Science, 527–533. IEEE Computer Society (2009)
Chailloux, A., Kerenidis, I.: Optimal bounds for quantum bit commitment. In: Proceedings of the 52nd Annual IEEE Symposium on Foundations of Computer Science, 354–362. IEEE Computer Society Press (2011). doi:10.1109/FOCS.2011.42
Gutoski, G., Watrous, J.: Toward a general theory of quantum games. In: Proceedings of the Thirty-Ninth Annual ACM Symposium on Theory of Computing, pp. 565–574. ACM, New York, NY, USA (2007)
Kerenidis, I., Nayak, A.: Weak coin flipping with small bias. Inf. Process. Lett. 89(3), 131–135 (2004). doi:10.1016/j.ipl.2003.07.007
Kitaev, A.: Quantum coin-flipping (2002). Unpublished result. Talk in the 6th Annual workshop on Quantum Information Processing, QIP 2003 Berkeley. CA, USA, December 2002
Lo, H.K., Chau, H.F.: Is quantum bit commitment really possible? Phys. Rev. Lett. 78(17), 3410–3413 (1997). doi:10.1103/PhysRevLett.78.3410
Lo, H.K., Chau, H.F.: Unconditional security of quantum key distribution over arbitrarily long distances. Science 283, 2050–2056 (1999)
Mayers, D.: Unconditionally secure quantum bit commitment is impossible. Phys. Rev. Lett. 78(17), 3414–3417 (1997). doi:10.1103/PhysRevLett.78.3414
Mayers, D.: Unconditional security in quantum cryptography. J. ACM 48(3), 351–406 (2001)
Mochon, C.: A large family of quantum weak coin-flipping protocols. Phys. Rev. A 72(2), 022341 (2005). doi:10.1103/PhysRevA.72.022341
Mochon, C.: Quantum weak coin flipping with arbitrarily small bias. Available as arXiv:quant-ph/0711.4114 (2007)
Molina, A., Vidick, T., Watrous, J.: Optimal counterfeiting attacks and generalizations for Wiesner’s quantum money. In: Proceedings of the 7th Conference on Theory of Quantum Computation, Communication, and Cryptography, pp. 45–64 (2012)
Nayak, A., Shor, P.W.: On bit-commitment based quantum coin flipping. Phys. Rev. A 67(1), 012304 (2003). doi:10.1103/PhysRevA.67.012304
Nielsen, M., Chuang, I.L.: Quantum Computation and Quantum Information. Cambridge University Press, New York, USA (2000)
Preskill, J., Shor, P.W.: Simple proof of security of the BB84 quantum key distribution protocol. Phys. Rev. Lett. 85(2), 441–444 (2000)
Shor, P.W.: Polynomial-time algorithms for prime factorization and discrete logarithms on a quantum computer. SIAM J. Comput. 26(5), 1484–1509 (1997)
Spekkens, R.W., Rudolph, T.: Degrees of concealment and bindingness in quantum bit commitment protocols. Phys. Rev. A 65, 012310 (2001). doi:10.1103/PhysRevA.65.012310
Sturm, J.F.: Using SeDuMi 1.02, a MATLAB toolbox for optimization over symmetric cones. Optim. Methods Softw. 11, 625–653 (1999)
Sturm, J.F.: Implementation of interior point methods for mixed semidefinite and second order cone optimization problems. Optim. Methods Softw. 17(6), 1105–1154 (2002)
Tunçel, L., Wolkowicz, H.: Strong duality and minimal representations for cone optimization. Comput. Optim. Appl. 1–30 (2012). doi:10.1007/s10589-012-9480-0
Wiesner, S.: Conjugate coding. SIGACT News 15(1), 78–88 (1983). doi:10.1145/1008908.1008920
Wolkowicz, H., Saigal, R., Vandenberghe, L.: Handbook of Semidefinite Programming. Kluwer Academic Publishers (2000)
Yao, A.C.C.: Some complexity questions related to distributive computing. In: Proceedings of the Eleventh Annual ACM Symposium on Theory of Computing, STOC ’79, pp. 209–213. ACM, New York, USA (1979). doi:10.1145/800135.804414
Yao, A.C.C.: Quantum circuit complexity. In: Proceedings of the 34th Annual IEEE Symposium on Foundations of Computer Science, pp. 352–361. IEEE Computer Society Press, Los Alamitos, CA, USA (1993)
Acknowledgments
We thank Andrew Childs, Michele Mosca, Peter Høyer, and John Watrous for their comments and suggestions. A.N.’s research was supported in part by NSERC Canada, CIFAR, an ERA (Ontario), QuantumWorks, and MITACS. A part of this work was completed at Perimeter Institute for Theoretical Physics. Perimeter Institute is supported in part by the Government of Canada through Industry Canada and by the Province of Ontario through MRI. J.S.’s research is supported by NSERC Canada, MITACS, ERA (Ontario), ANR Project ANR-09-JCJC-0067-01, and ERC Project QCC 306537. L.T.’s research is supported in part by Discovery Grants from NSERC. Research at the Centre for Quantum Technologies at the National University of Singapore is partially funded by the Singapore Ministry of Education and the National Research Foundation, also through the Tier 3 Grant “Random numbers from quantum processes,” (MOE2012-T3-1-009).
Author information
Authors and Affiliations
Corresponding author
Electronic supplementary material
Below is the link to the electronic supplementary material.
Rights and permissions
About this article
Cite this article
Nayak, A., Sikora, J. & Tunçel, L. A search for quantum coin-flipping protocols using optimization techniques. Math. Program. 156, 581–613 (2016). https://doi.org/10.1007/s10107-015-0909-y
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10107-015-0909-y