SuperCrypt: A Novel Technique of Quantum Cryptography
Simultaneously Improving Both Security Level and Data Rate
Kazi Sinthia Kabir, and Tusher Chakraborty
Email: [email protected], [email protected]
Qubit (quantum bit): The basic unit in quantum
computation, which is a linear superposition of 0 and
1 [1]. A qubit is generally represented as follows,
where and determine the corresponding extents
of superposition.
Quantum entanglement: A quantum mechanical
phenomenon that describes quantum states of two
objects with reference to each other, even though the
individual objects may be spatially separated [1].
Superdense Coding: A Method of quantum
communication to increase the rate of transferred
data [2].
Quantum Cryptography: Use of quantum
computation to perform cryptographic tasks [1].
Security in traditional quantum cryptography is
based on selection of a basis for measurement of
photons, which carry the values of qubits.
If an intruder fails to select the basis correctly, he
cannot extract the data.
System Model of
Our Proposed Technique
Steps at the Sender Side
1.Encode the message with key
using XOR operation.
2.Permute the bit positions of the
key according to predefined rules
known both by sender and receiver.
Key : 1 0 1 1 0 0 1 0
Permutated
key : 0 1 0Coding
0 1 1 1 of
0
3.Perform
Superdense
the modified key string.
4.Send the Superdense coded
photons for transmitting the key.
Sender
Key
Receiver
Message
XOR
Encoded
message
Encoded
message
Encoded message
transmission
Modified key
01001110
Key bit positions Photon position
1
5
1
4
8
2
2
7
3
3
6
4
Superdense
Coding
Superdense
coded key
Our system largely depends on
entanglement of qubits. However, if a
qubit is measured, its entanglement is
destroyed.
Therefore, we propose to utilize either of
the following methods:
Recycling qubits [3], and
Re-establishing entanglement [5].
Complexity Analysis
01001110
Key
Modified key
Key
transmission
Photon position Key bit positions
1
1
5
2
4
8
3
2
7
4
3
6
Reverse
Permutation
Table: Bit selection for Superdense Decoding
Superdense 3.Permute the bit positions of the key
Decoding
in a reverse manner according to
Superdense
predefined rules to extract the original
coded key
key.
Figure: Block diagram of proposed encryption technique.
Received key : 0 1 0 0 1 1 1 0
Reverse Permutated Key: 1 0 1 1 0 0 1 0
4.Decode the message using XOR
operation with the key.
Table: Bit selection for Superdense Coding
Recycling Qubits
1.Receive the Superdense coded
photons.
2.Decode from the Superdense coded
form.
Message
XOR
Permutation
Steps at the Receiver Side
Conclusion and Future Work
As even quantum encryption comes under
security threats in recent times, we propose a
highly-secure technique of quantum encryption
with higher information transfer rate.
The computational power of practical
quantum computers is increasing day-by-day,
which might cause threat even to our proposed
technique in future. Therefore, we plan to
incorporate a third level of encryption by
changing the basis of photon to make the
system more secured.
We plan to explore synchronization between
the information transmitted through the
quantum channel and the classical channel.
We also plan to perform simulation of our
proposed system.
References
[1] A. V. Sergienko, Quantum communications and
cryptography, Taylor and Francis, 2006.
[2] C. G. Yale, B. B. Buckley, D. J. Christle,L. C.
Bassett, and D. D. Awschalom, All-optical control of
a solid-state spin using coherent dark states,
National Academy of Sciences, vol. 110, no. 19, pp.
75957600, 2013.
[3] University of Bristol. "Quantum computing with
recycled particles." ScienceDaily. 23 October 2012.
www.sciencedaily.com/releases/2012/10/121023112
515.htm
Last accessed: 22 March, 2015.
[4] C. H. Bennett and S. J.Wiesner, Communication
via one-and twoparticle operators on einsteinpodolsky-rosen states Physical review letters, vol.
69, p. 2881, 1992.
[5] Abdi, Mehdi, Paolo Tombesi, and David Vitali.
"Entangling two distant noninteracting microwave
modes." Annalen der Physik 527.1-2, 2015.
Department of Computer Science and Engineering (CSE), BUET
