Quantum Key Distribution with Multiple
Photons for Secure Communications over
Cloud
Chamundeswari K1, G.Murali2
Student, Department of CSE, JNTUACEP, Pulivendula, India 1
Asst.Professor, Department of CSE, JNTUACEP, Pulivendula, India 2
Abstract--Security plays an important role in all communications networks. Quantum key cryptography is said to
provide security that can’t be broken. Classical cryptography has security problems as the security depends on the
computational complexity of the keys. There are some implementations of QKD protocols such as BB84. However,
these protocols are susceptible to attacks such as siphoning attack which needs to be addressed. Many quantum key
distribution protocols came into existence after initial protocol implementation in the form of BB84. These protocols
have problem with respect to siphoning attacks. Recently a solution is provided by Mandal et al. where they
implemented a three stage QKD process. In this paper we used the same concepts and implemented a prototype
application that provides classical public channel while making use of a simulator that mimics the QKD in quantum
channel. The experimental results reveal that the proposed application is provably secure. Moreover we deployed the
application in cloud and the quantum experiments with cloud are to be left for future work.
Keywords – Security, quantum cryptography, classical cryptography, QKD
I.
INTRODUCTION
Cryptography has been around for securing
communications over networks. The evolution
process
witnessed
symmetric
cryptography,
asymmetric cryptography and quantum cryptography.
Symmetric cryptography has a drawback such as key
sharing as the same key is used by sender and
receiver of information. This makes it vulnerable to
attacks. The asymmetric cryptography makes use of
key pairs so as to ensure that all participants in
communication are having two keys namely private
key and public key. The public key is informed to all
participants while the private key remains secret and
known to only that participant. In this scenario
encryption is made using the public key of the
recipient while decryption is made with private key
of the recipient thus eliminating the need for key
sharing. This will make asymmetric cryptography
more secure than its symmetric counterpart. The
security of traditional cryptography is based on the
strength of the keys while quantum key cryptography
is said to provide security that can’t be broken.
Classical cryptography has security problems as the
security depends on the computational complexity of
the keys. However, quantum cryptography is a
misnomer as it really does not involve in encryption
and decryption procedures. It is only meant for
quantum key distribution
illustrates this process.
securely.
Figure
1
Figure 1 – Differences between classical channel and
quantum channel
BB84 [1] is the first protocol that demonstrates
quantum key distribution. Provably secure
communications [2] are possible with such key
distribution mechanism. As can be seen in Figure 1, it
is evident that there two channels. The quantum
channel only takes care of secure key distribution
while that key is used by classical public channel in
order to provide fool proof security to the real world
communications over the network.
In this paper we built a prototype application that
demonstrates the secure communications over
classical public channel while it makes use of QKD
process provided by a simulator program. With this
and the concepts provided in [3], experiments are
made to test the application. In literature other
solutions found include [4], [5], [6], [7], [8], [9], [10],
and [11]. The empirical results are encouraging with
100% security every time. As cloud computing
became popular we also tried the application
deployment in cloud. The empirical results reveal
that the application can be accessed through cloud
from any corner of the world without time and
geographical restrictions.
results while section V concludes the paper and
provides directions for future work.
II.
IMPLEMENTATION
We built a prototype application that demonstrates
the concept of classical cryptography powered by
quantum key distribution. Our implementation of
quantum distribution is influenced by the work done
in [3] where a three stage protocol and its dynamics
are presented. The protocol is based on the “no
cloning theorem” which is based on the quantum
states in the quantum theory. This theorem forbids
the creation of identical quantum states. It was
originally stated by Wootters et al. in 1982. The
theorem proves the cloning of photons is not
possible. Our implementation also exhibits quantum
entanglement where quantum states of particles
cannot be disclosed independently. It does mean that
the quantum channel will be able to identify
eavesdropping (or it experiences embarrassment
when such thing happens). Entanglement helps
quantum channel behave predicatively when
eavesdropping is suspected.
Figure 2 – Cloud platform
As can be seen in Figure 2, it is evident that the cloud
computing provides services such as software as a
service, platform as a service and infrastructure as a
service. As the cloud applications and cloud users are
growing day by day, it is understood that the cloud
based applications become dominant in the near
future in the real world. This thought helped us to
push our application forward and tailored it to deploy
in cloud server. Thus the application is made a
scalable, secure solution that has no time and
geographical restrictions besides making the
application intuitive with classical public channel.
The remainder of the paper is structured as follows.
Section II provides review of literature on the QKD
process and related works. Section III presents the
proposed solution. Section IV presents experimental
Figure 3 – Important of no cloning theorem
As can be seen in Figure 3, it is evident that the
quantum channel cannot be really subjected to
cloning of photons in order to eavesdrop or break
security. Adversaries cannot perform closing
operations for various kinds of attacks on quantum
channel. Quantum entanglement and no cloning
theory attributed to quantum channel make it a
provably secure key distribution channel that
quarantines fool proof security. The data channel or
classical public channel makes use of the secret key
that has been distributed through quantum channel
for performing cryptographic primitives in order to
have secure communication over communication
networks. Eve can never eavesdrop when there is
quantum entanglement in place or even cannot clone
photons for violating secure communications over the
network.
place. However, the basis for fool proof security is
with the quantum channel that ensures provably
secure key distribution. Both channels when work
together, it is possible to have the expected security
to application that can never be broken. For the
purpose of quantum key distribution, we made use of
a simulator that mimics quantum channel. This is
done to have laboratory experiments to test the
prototype application. The simulation program that
generates quantum states and thus keys is as
presented in Figure 5.
Figure 4 – Virtual photons
As can be seen in Figure 4, it is evident that virtual
photons are absorbed and resultant force is released.
There are virtual photons that are exchanged
continuously in order to generate electromagnetic
force. The virtual photons and the quantum
entanglement and the no cloning theorem are the
basis for the secure key distribution in quantum
channel. When key distribution is successful as it
should be quantum channel, it is possible that that
classical public channel makes use of the secret keys
and performs traditional cryptographic operations so
as
to
ensure
unconditional
security
to
communications over network.
III.
EXPERIMENTAL RESULTS
We built prototype application that demonstrates the
proof of concept. The environment used for
implementation of the application includes a PC with
2 GB RAM, core 2 dual processor running Windows
operating system. For web application development
Java/J2EE platform is used. The UI is built using JSP
pages while the Servlets technology performs server
side processing. There is secure communication
demonstrated using the application. The application
layer of the OSI model is used to perform various
security operations such as encryption, decryption
and quantum key distribution. As discussed earlier in
this paper, we used the application and its
cryptographic primitives in classical public channel
or data channel where secure communications take
Figure 5 – QKD simulator
As can be seen in Figure 5, it is evident that the
quantum states generated by the simulator are
captured and used in the classical public channel of
the application. The application makes use of the
quantum security principles and performs encryption
and decryption operations that cannot be broken due
to QKD which is unconditionally secure. The
quantum channel successfully addresses the problems
when attackers launch attacks and try to eavesdrop
the quantum channel. The quantum entanglement is
in place and such attempts are neighter successful nor
useful in cloning photons in order to reuse it later for
other attacks. The adversaries’ attempt goes in vain
as the quantum channel is used for key distribution
while traditional cryptographic operations are
performed using the keys distributed over quantum
channel. Here our efforts are limited to building an
application that makes use of the simulator that can
mimic the quantum channel.
Accuracy Percentage
Performance
Analysis
100
50
0
1
2
3
Experiments
Figure 8 – Performance analysis
Figure 6 – Application showing content before
encryption
As can be seen in Figure 6, the application has
provision for encryption and decryption in classical
public channel. It has provision for encryption and
decryption operations in the channel while the secure
key distribution is left to the simulation
demonstrating QKD process. The encrypted content
is as shown in Figure 7.
As can be seen in Figure 8, it is evident that there are
three experiments made with the prototype
application that demonstrates classical public channel
and takes the help of a simulator for QKD. In each
experiment, the fool proof security is proven with
100% accuracy. These experiments are made using
both the channels for secure communications. The
empirical results reveal that the proposed application
is useful for secure communications besides having
the ability to overcome potential threats while
delivering intended services.
After making such experiments successfully we
deployed the application in cloud. The application is
in public cloud does mean that it can be accessed
from any corner of the world as it does not put time
and geographical restrictions in pace. The
deployment of the application in cloud is for
demonstrating the cloud usage of such application.
However, cloud computing experiments with
quantum channel are left for future work.
IV.
CONCLUSION
AND
FUTUREWORK
Figure 7 – Encryption result
As can be seen in Figure 7, the content of files
presented on web pages is in encrypted format that
can’t be understood by humans. Again it can be
decrypted using the classical public channel as
described earlier. However, the key distribution
process as usual is done using the quantum channel
that is encapsulated by the simulator program.
In this paper, we studied quantum key distribution
processes and implemented an application that
demonstrates the communications with 100%
security. Quantum entanglement and no clone
theorem are in place in order to provide fool proof
security. Three stage protocol proposed by Mandal et
al. [3] is basis for our experiments. The secure key
distribution through quantum channel is done with
the help of simulator program available in Java. The
simulator program mimics the QKD which is used
for laboratory experiments. The proposed application
is able to capture the quantum channel results in
order to perform conventional cryptography
operations such as encryption and decryption. Thus it
is evident that quantum channel is used for only QKD
process while the classical public channel is best used
for communications where traditional security
mechanism can be used. There is synergic effect
visible in the experiments as both the channels work
together seamlessly. The prototype application is
capable of demonstrating the proof of concept. The
empirical results are encouraging. We also tried to
deploy the application in cloud. We made it public
through cloud deployment that can help the
application to be accessed by people without time
and geographical restrictions. One direction for future
work is to implement the protocol and use it in a real
network instead of simulations. In other words in
future we intend to explore the quantum channel in a
real cloud computing.
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