Hi all,
today we're in K52. Emily Adlam, visiting from Cambridge, will give
the talk. See below for title and abstract.
Best,
-joe
Title: In Which Alice is a Know-It-All and Bob Never Learns
Abstract: Bob has a black box that emits a single pure state qudit
which is, from his perspective, uniformly distributed. Alice wishes to
give Bob evidence that she has knowledge about the emitted state while
giving him little or no information about it. We show that
zero-knowledge evidencing of such knowledge is impossible in quantum
relativistic protocols, extending a previous result of Horodecki et
al. We also show that no such protocol can be both sound and complete.
We present a new quantum relativistic protocol which we conjecture to
be close to optimal in security against Alice and which reveals little
knowledge to Bob, for large dimension d. We analyse its security
against general attacks by Bob and restricted attacks by Alice.