## Profile
## Outputs
Title | Category | Date | Authors |
Graph states and ramp schemes for quantum secret sharingI will discuss our recent work in developing new protocols for quantum secret sharing (QSS), a cryptographic scheme in which an encoded quantum "secret" is divided between several "players" such that only certain subsets of players may recover it. We have found a class of protocols based on graph states which allow for efficient (i.e. player states of the same dimension as the secret) QSS for states of prime dimension. We have also found examples of "ramp" schemes for QSS, in which the efficiency can be improved by sacrificing some security. I will discuss these and the use of shared entanglement as a measure of the players' information about the secret.
University of Calgary | Presentation | 2011-02-24 | B. Fortescue, A. Keet, D. Markham, G. Gour, B. C. Sanders | Quantum secret sharing with qudit graph statesWe present a formalism for quantum secret sharing using graph states of systems with prime dimension. As we show, such states allow for a unified structure for the sharing of classical and quantum secrets over both classical and quantum channels. We give explicit protocols for three varieties of threshold secret sharing within this formalism. Joint work with Adrian Keet and Barry C. Sanders. University of Calgary | Presentation | 2010-02-20 | B. Fortescue, A. Keet, B. C. Sanders, D. Markham | Threshold quantum secret sharing using graph states of prime-dimensional systemsSecret sharing schemes allow a classical or quantum secret to be divided among many parties such that it can be recovered only by some specified set of parties collaborating in order to do so. It is known that arbitrary secret sharing schemes may be constructed by concatenating threshold schemes, in which the secret can be recovered by any sufficiently large number of parties, and the remainder are denied any knowledge of the secret
I will discuss a formalism within which, using entangled graph states of prime-dimensional systems, a variety of different threshold secret sharing schemes (involving both quantum and classical secrets and quantum and classical channels shared between parties) may be unified. I will give explicit protocols for three varieties of secret sharing within this formalism, including some for which the analogous formalism using graph states of two-dimensional systems is not sufficient. University of Calgary | Presentation | 2010-07-19 | B. Fortescue, A. Keet, D. Markham, B. C. Sanders | Secret sharing with higher-dimensional graph states University of Calgary | Presentation | 2010-08-26 | B. Fortescue, A. Keet, D. Markham, B. C. Sanders | New directions in quantum secret sharing University of Calgary | Presentation | 2010-11-19 | B. Fortescue, A. Keet, D. Markham, G. Gour, B. C. Sanders |
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