Southwest Quantum Information and Technology

Things you can do with your quantum key distribution setup: signatures and oblivious transfer

Presenting Author: Erika Andersson, Herriot-Watt University

Modern cryptography is more than encryption, and quantum cryptography is more than quantum key distribution. "Quantum digital signatures” were first proposed by Gottesman and Chuang in 2001, inspired by public-key signature schemes. Broadly speaking, a signature guarantees that a message cannot be altered or forged. There can be more than one possible recipient, and messages can be forwarded from one recipient to another. The first quantum signature scheme developed into something more practical, essentially using the same experimental components as quantum key distribution. This led to realisations of measurement-device-independent quantum signatures at Toshiba, Cambridge, and by J-W Pan’s group in China. Oblivious transfer is another functionality different from encryption. In 1-out-of-2 oblivious transfer, a receiver obtains only one of two bits sent by a sender. The sender does not know which of the two bits the receiver obtains, and the receiver does not know the other bit. Such a “poor communication channel” is, perhaps surprisingly, an important primitive for secure multiparty computation. Quantum oblivious transfer is possible, but with some limitations. In the second half of this talk, I will describe a scheme for quantum oblivious transfer that works at least as well than any of the previous ones, and which only needs the same components as standard quantum key distribution.

(Session 8 : Monday from 1:30pm - 2:15pm)