Text Size
Facebook Twitter More...

"Post-Quantum" Cryptography

In quantum key distribution schemes, Alice and Bob exchange quantum and classical information in order to generate a shared secret key. There are several well-known schemes, which are provably secure against eavesdropping, so long as quantum theory is correct. But what if quantum theory isn't correct? This might seem a rather academic question, since quantum theory has been confirmed in an impressive range of experiments since 1926. But cryptologists are supposed to examine their assumptions carefullyPhysical theories have been superseded in the past, and there's no strong reason to think it won't happen again. (And in fact, although it's a minority view, there is a very respectable case for believing that the lingering conceptual problems in interpreting quantum theory point to some subtle defect in the theory itself.) You can't prove anything secure without making some assumptions, and in particular you can't prove any physics-based cryptography scheme secure without making some assumptions about physics. But Jonathan Barrett, Lucien Hardy and I were recently able to show that a quantum key distribution scheme can be proved secure even if quantum theory is incorrect, so long as we assume that (as special relativity suggests) it is impossible to send signals faster than light. The scheme is, admittedly, very inefficient, but it's at least a proof of principle that security guarantees can be based on either of two independent theories (quantum mechanics and special relativity), rather than on one alone. It would be very interesting to know if significantly more efficient schemes exist, or indeed if the security of standard quantum key distribution schemes can also be based on relativity. There's a popular account of this work in Physical Review Focus, linked here.  ... Bit commitment is one of the main primitives of mistrustful cryptography, the branch of cryptography dealing with parties who need to exchange or process information but cannot rely on each other's honesty. ...  It turns out, though, that secure (and practically feasible) bit commitment protocols can be implemented if Alice and Bob use separated sites and take account of the impossibility of signalling faster than light. "

Of course Adrian Kent's's result above is kind of obvious, but it's always good to prove things rigorously when you can. The fact of the matter, however, in my opinion, is that all living matter is able to in effect send signals faster than light because the very essence of life is sub-quantal non-equilibrium of the Bohm hidden variable matter degrees of freedom.


Category: MyBlog

Categories ...

't Hooft 100 Year Star Ship Abner Shimony accelerometers action-reaction principle Aephraim Sternberg Alan Turing Albert Einstein Alpha Magnetic Spectrometer American Institute of Physics Andrija Puharich Anthony Valentin Anton Zeilinger Antony Valentini anyon Apple Computer Artificial Intelligence Asher Peres Back From The Future Basil Hiley Bell's theorem Ben Affleck Ben Libet Bernard Carr Bill Clinton black body radiation Black Hole black hole firewall black hole information paradox black holes Bohm brain waves Brian Josephson Broadwell Cambridge University Carnot Heat Engine Central Intelligence Agency CIA Clive Prince closed time like curves coherent quantum state Consciousness conservation laws Cosmic Landscape Cosmological Constant cosmology CTC cyber-bullying Dancing Wu Li Masters Dark Energy Dark Matter DARPA Daryl Bem David Bohm David Deutsch David Gross David Kaiser David Neyland David Tong de Sitter horizon Dean Radin Deepak Chopra delayed choice Demetrios A. Kalamidas Demetrios Kalamidas Dennis Sciama Destiny Matrix Dick Bierman Doppler radars E8 group Einstein's curved spacetime gravity Einstein's happiest thought electromagnetism Eli Cartan EMP Nuclear Attack entanglement signals ER=EPR Eric Davis Ernst Mach ET Eternal Chaotic Inflation evaporating black holes Facebook Faster-Than-Light Signals? fictitious force firewall paradox flying saucers FQXi Frank Tipler Frank Wilczek Fred Alan Wolf Free Will G.'t Hooft Garrett Moddel Gary Zukav gauge theory general relativity Geometrodynamics Gerard 't Hooft Giancarlo Ghirardi God Goldstone theorem gravimagnetism gravity Gravity - the movie gravity gradiometers gravity tetrads Gravity Waves Gregory Corso gyroscopes hacking quantum cryptographs Hagen Kleinert Hal Puthoff Hawking radiation Heisenberg Henry Stapp Herbert Gold Higgs boson Higgs field hologram universe Horizon How the Hippies Saved Physics I.J. Good ICBMs Igor Novikov inertial forces inertial navigation Inquisition Internet Iphone Iran Isaac Newton Israel Jack Sarfatti Jacques Vallee James F. Woodward James Woodward JASON Dept of Defense Jeffrey Bub Jesse Ventura Jim Woodward John Archibald Wheeler John Baez John Cramer John S. Bell Ken Peacock Kip Thorne Kornel Lanczos La Boheme Laputa Large Hadron Collider Lenny Susskind Leonard Susskind Levi-Civita connection LHC CERN libel Louis de Broglie Lubos Motl LUX Lynn Picknett M-Theory Mach's Principle Mae Jemison Making Starships and Star Gates Martin Rees Mathematical Mind MATRIX Matter-AntiMatter Asymmetry Max Tegmark Menas Kafatos Michael Persinger Michael Towler microtubules Milky way MIT MOSSAD multiverse NASA Nick Bostrum Nick Herbert Nobel Prize nonlocality Obama organized-stalking Origin of Inertia P. A. M. Dirac P.K.Dick P.W. Anderson Paranormal parapsychology Paul Werbos Perimeter Institute Petraeus Physical Review Letters Physics Today Post-Quantum Physics pre-Big Bang precognition presponse PSI WARS Psychic Repression qualia Quantum Chromodynamics quantum computers quantum entanglement quantum field theory quantum gravity Quantum Information Theory Quantum Theory RAF Spitfires Ray Chiao Red Chinese Remote Viewing retrocausality Reviews of Modern Physics Richard Feynman Richard P. Feynman Rindler effect Robert Anton Wilson Robert Bigelow Roger Penrose rotating black holes Roy Glauber Rupert Sheldrake Russell Targ Ruth Elinor Kastner S-Matrix Sagnac effect Sam Ting Sanford Underground Research Facility Sarfatti Lectures in Physics Scientific American Second Law of Thermodynamics Seth Lloyd signal nonlocality Skinwalker Ranch social networks space drive space-time crystal SPECTRA - UFO COMPUTER spontaneous broken symmetry SRI Remote Viewing Experiments Stanford Physics Stanford Research Institute Star Gate Star Ship Star Trek Q Stargate Starship Stephen Hawking Steven Weinberg stretched membrane string theory strong force gluons Stuart Hameroff superconducting meta-material supersymmetry symmetries telepathy Templeton The Guardian Thought Police time crystal time travel topological computers Topological Computing torsion UFO Unitarity unitary S-Matrix false? Unruh effect Uri Geller VALIS virtual particle Virtual Reality Warp Drive weak force Wheeler-Feynman WIMP WMAP WMD world crystal lattice wormhole Yakir Aharonov Yuri Milner