quantum key encryption
this is a bout the only reason I regret having a job. I can't attend some of the really awesome physics talks held here.
Take, for example, a cute method for secure key generation (shall I say ultra secure, since they can only come in pairs and can't be copied?)
Quantum key expansion allows two separated parties to accomplish what seems logically impossible: unconditionally-secure expansion of a shared secret key using an untrusted means of quantum communication along with public classical communication. On the quantum side, the parties need only prepare, transmit, and measure individual quantum states. All subsequent "key distillation" operations are then performed on the raw classical output data. The security of the procedure can be traced back to entanglement by describing the entire procedure in quantum-mechanical terms. Key distillation becomes entanglement distillation, though the entanglement is virtual and not physical. Since maximal entanglement cannot be shared by more than two parties, keys generated from it are unknown to any eavesdropper. However, maximally entangled states are not the only states which produce private keys; these are generally termed "twisted states" or private states. In this talk I will show how to modify the usual picture of key expansion as entanglement distillation to include twisted states. Fortunately, the usual methods of entanglement distillation suffice for this purpose, with the added benefit that some portion of the phase errors need not be corrected at all. This modification also nicely resolves a recently-discovered paradoxical effect that making errors while distilling the key can actually improve the protocol's overall resistance to eavesdropping.
More on quantum key encryption
Hehehe...
Take, for example, a cute method for secure key generation (shall I say ultra secure, since they can only come in pairs and can't be copied?)
Quantum key expansion allows two separated parties to accomplish what seems logically impossible: unconditionally-secure expansion of a shared secret key using an untrusted means of quantum communication along with public classical communication. On the quantum side, the parties need only prepare, transmit, and measure individual quantum states. All subsequent "key distillation" operations are then performed on the raw classical output data. The security of the procedure can be traced back to entanglement by describing the entire procedure in quantum-mechanical terms. Key distillation becomes entanglement distillation, though the entanglement is virtual and not physical. Since maximal entanglement cannot be shared by more than two parties, keys generated from it are unknown to any eavesdropper. However, maximally entangled states are not the only states which produce private keys; these are generally termed "twisted states" or private states. In this talk I will show how to modify the usual picture of key expansion as entanglement distillation to include twisted states. Fortunately, the usual methods of entanglement distillation suffice for this purpose, with the added benefit that some portion of the phase errors need not be corrected at all. This modification also nicely resolves a recently-discovered paradoxical effect that making errors while distilling the key can actually improve the protocol's overall resistance to eavesdropping.
More on quantum key encryption
Hehehe...