3,762 research outputs found
The relationship between two flavors of oblivious transfer at the quantum level
Though all-or-nothing oblivious transfer and one-out-of-two oblivious
transfer are equivalent in classical cryptography, we here show that due to the
nature of quantum cryptography, a protocol built upon secure quantum
all-or-nothing oblivious transfer cannot satisfy the rigorous definition of
quantum one-out-of-two oblivious transfer.Comment: 4 pages, no figur
The Oblivious Transfer Capacity of the Wiretapped Binary Erasure Channel
We consider oblivious transfer between Alice and Bob in the presence of an
eavesdropper Eve when there is a broadcast channel from Alice to Bob and Eve.
In addition to the secrecy constraints of Alice and Bob, Eve should not learn
the private data of Alice and Bob. When the broadcast channel consists of two
independent binary erasure channels, we derive the oblivious transfer capacity
for both 2-privacy (where the eavesdropper may collude with either party) and
1-privacy (where there are no collusions).Comment: This is an extended version of the paper "The Oblivious Transfer
Capacity of the Wiretapped Binary Erasure Channel" to be presented at ISIT
201
Spacetime-constrained oblivious transfer
In 1-out-of-2 oblivious transfer (OT), Alice inputs numbers x_0, x_1, Bob
inputs a bit b and outputs x_b. Secure OT requires that Alice and Bob learn
nothing about b and x_{\bar{b}}, respectively. We define spacetime-constrained
oblivious transfer (SCOT) as OT in Minkowski spacetime in which Bob must output
x_b within R_b, where R_0 and R_1 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.Comment: Improved theorem on the impossibility of classical SCOT to allow for
small errors. Figure added and discussion extended in response to referee
comments. Protocol and security proof unaltered. Final versio
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