Speaker: Erika Andersson, Heriot-Watt University, Edinburgh, Scotland

Title: Quantum digital signatures

Abstract:

Digital signatures ensure that messages cannot be forged or tampered with. They are widely used to provide security for electronic communications, for example in financial transactions and electronic mail. Importantly, signed messages are also transferrable, meaning that if one recipient accepts a message as genuine, then she is guaranteed that others will also accept the same message if it is forwarded. Digital signatures are different from encryption, which guarantees the privacy of a message.  Currently used classical digital signature schemes, however, only offer security relying on unproven computational assumptions. In contrast, quantum digital signatures (QDS), similar to quantum key distribution (QKD), offer information-theoretic security based on principles of quantum mechanics. A serious drawback of previous QDS schemes is however that they require long-term quantum memory, making them unfeasible. We present protocols which do not need quantum memory and which use only standard linear optical components and photodetectors. With this, it seems that QDS and QKD are similar in terms of experimental requirements. Important work remains in investigating which QDS schemes are most suited for real applications, and in completing full security proofs.

Coffee/tea and cake will be available from 15:00