Cryptography Reference
In-Depth Information
4
{1} adversary
structure
3
{2,3}
access
structure
2
0.04
{1,2} access
structure
0.03
0.02
1
0.01
0
1.6
1.7
1.8
1.9
2
T
0
0
0.2
0.4
0.6
0.8
1
T
Figure 8.11
Experimental signal transfer (
T
) and additional reconstruction noise (
V
)
for the
access structure for varying gain, and the adversary structure. Solid line:
calculated theoretical curve with squeezing of
{
2,3
}
3.5 dB, elec-
tronic noise of -13 dB with respect to the quantum noise limit, and feedforward detector
efficiency of 0.93. Gray area: the classical boundary for the
−
4.5 dB, added noise of
+
{
2,3
}
access structure. (Inset)
Experimental
T
and
V
for the
{
1,2
}
access structure (gray points) and the theoretical
point (black point).
to demonstrations of the individual components required for their success,
such as quantum memory [26], and quantum gates [27]. Apart from achiev-
ing these components in isolation, it is essential that quantum information
networks are scalable, both in terms of the complexity of problems solvable
within a node, and in terms of the total number of nodes involved.
Quantum state sharing allows many nodes to cooperate on a specific
computing problem as with distributed computing, and it naturally extends
the number of nodes that can be involved in any quantum information pro-
tocol. Suppose, as an example, that a group of people who do not trust each
other want to crack a code using Shor's algorithm [28]. Suppose also that the
group has only one quantum computer powerful enough to realize this algo-
rithm. They can ask the person owning this quantum computer to perform
most, but not all, of the steps in Shor's algorithm and to use the quantum
state sharing protocol to distribute the partial results to the other members
of the group. Finally, an access structure can reunite, and with a smaller, less
powerful quantum computer complete Shor's algorithm to crack the code.
These properties, coupled with its ability to facilitate quantum error cor-
rection, as discussed below, suggest that quantum state sharing is an impor-
tant tool for scalable quantum information networks.
