Abstract
In 1-out-of-2 oblivious transfer (OT), Alice inputs numbers , Bob inputs a bit and outputs . Secure OT requires that Alice and Bob learn nothing about and , respectively. We define spacetime-constrained oblivious transfer (SCOT) as OT in Minkowski spacetime in which Bob must output within , where and are fixed spacelike separated spacetime regions. We show that unconditionally secure SCOT is impossible with classical protocols in Minkowski (or Galilean) spacetime, or with quantum protocols in Galilean spacetime. We describe a quantum SCOT protocol in Minkowski spacetime, and we show it unconditionally secure.
- Received 20 November 2015
- Revised 26 April 2016
DOI:https://doi.org/10.1103/PhysRevA.93.062346
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