IRJET- Enhanced Cloud Data Security using Combined Encryption and Steganography

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 05 Issue: 03 | Mar-2018 www.irjet.net p-ISSN: 2395-0072
© 2018, IRJET | Impact Factor value: 6.171 | ISO 9001:2008 Certified Journal | Page 1856
Enhanced Cloud Data Security using Combined Encryption and
Steganography
Acqueela G Palathingal1, Anmy George 2, Blessy Ann Thomas 3, Ann Rija Paul4
1,2,3 B.Tech Student, Dept. of Computer Science Engineering, Sahrdaya College of Engineering & Technology,
Kerala, India
4 Assistant Professor, Dept. of Computer Science Engineering, Sahrdaya College of Engineering & Technology,
Kerala, India
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Abstract - Security has become a wide necessity in day-to-
day life. Data security is the most obliged security of all. The
data in our system is opened to high potential risks. Due to
various security reasons we adopt diverse methods. Now we
all are depending on cloud platform for security and storage
but even it is vulnerable to various threats. The data inside
cloud is not well-secured as it can be accessed by anyone who
can attain our credentials and also the cloud providers has
equal access that as of us. So we propose an enhanced security
to the data using encryption and steganography. Here the
data will be encrypted and hidden behind an image and hence
uploaded to the cloud. Whenever felt necessary the image
could be downloaded and the data can be decrypted to obtain
back the original file. Our results provide augmented security
to the data and can be used anywhere without qualms.
Key Words: Cloud computing, Cryptography, RSA,
Encryption, Decryption, DWT Steganography.
1. INTRODUCTION
The Cloud computing will be most important in Internet
of Services and computer infrastructure. Both applications
and resources are delivered to the Internet as services only
on demand in the cloud computing environment. Cloud
Computing is cost- effective, very flexible, and it provide
delivery platform to either businessor consumer ITservices
over the Internet. There are two basic types of functions in
Cloud computing. They are computing and data storage.The
Cloudmodels are Infrastructure as a service (IAAS) which is
for executing services by sharing the resourcesof hardware,
by using the technology of virtualization. Platform as a
service (PAAS) which offers a execution environment in
software like an application server. Software as a service
(SAAS) which completesall the applicationisontheinternet.
Cloud computing can be adopted by users and enterprise.To
make this adaptation, the user’s security concerns shouldbe
rectified first to make cloud environment trustworthy. The
basic requirement to win the user’s requirement is that the
trustworthy environment. In cloud computingenvironment,
Data security is more complicated than data security in the
traditional information systems.CloudComputingsecurityis
one that is more important to be addressed nowadays. If
security measures are not provided properly, then Data
operations and transmissions will be at high risk. To handle
these challenges, strongest security measuresaretobemade
and it has to be implemented by identifying security
challenge and its solution.
To recognize the tangible and intangible threatsrelatedtoits
use these securities, privacy will be used. There are some of
the major issues in the cloud computing environment and it
as follows: resource management, resource monitoring and
resource security. A data security framework for cloud
computing networks is proposed.
The privacy will be used to study about the tangible threats
and also the intangible threats, Some of the issues in data
security were privacy of data, protecting the data,
availability of data, etc. The various challenges in the
security were lossof data, data threats and maliciousattacks
from outsiders. The most challenging issue in cloud
computing is data sharing [1].
2. SYSTEM DESIGN
The work is dividing into mainly 3 parts. The first part is to
encrypt the file. The second part is to hide the encrypted
data behind an image. The third part is uploading the image
to the cloud. Whenever necessary the image can be
downloaded from the cloud platform and then the data can
be extracted and hence decrypted to get the original file.
2.1 Encryption
Encryption is the process to converting data or
information (plaintext) into another form, called ciphertext,
which cannot be easily understood by anyone except
authorized person. Decryption is the process to converting
cipher text back into plaintext. The main purpose of
encryption is to secure the confidentiality of digital data
stored on computer systems or transmitted via other
computer on network (internet). In process of encryption
and decryption we generate a key to time of data encryption
and use same or different key to decrypt the data.

Fig -1: RSA encryption system model
In this system RSA (Rivest-Shamir-Adleman) is used for
encryption process. Files are taken from the system and are
encrypted using this technique. Thos is a public key
cryptography where mainly 2 keys are used i.e., one for
encryption and the other for decryption. On the encryption
side we use to encrypt using the public key whereas in the
decryption face we use the private key.
2.2 Steganography
Steganography is communication that usesthe technique
of cloaked writing that aims at hiding the existence of any
message or data. Steganography has been in use for secret
communication since ancient timesin multiple forms.Inthis
technological era it is deployed for secured transfer of data
over digital channel in which the information is hidden in
some media. The information can be hidden in image, text,
audio or video and are called image steganography, text
steganography, audio or video steganography respectively.
Fig – 2: Steganography model
In this system steganography playsan importantrole.We
are using DWT Steganography. The secret message with the
cover image is given as the input and it isembeddedtogether
to form the stego object. This can be retrieved by extraction
process to acquire the original image and also gives back the
message. It does the role of hiding data.
2.3 Cloud Platform
Cloud is the environment where are opting for saving the
files and documents. It is basically a storage where all our
vital information is kept and acts as a backup in case of
system failure. There are diverse cloud service providers
nevertheless the data inside cloud is never safe. It is
necessary that our information must be confidential and
should not be disclosed easily.
3. IMPLEMENTATION
In this paper, we have used two techniques RSA encryption
and DWT steganography. These techniques give enhanced
security for the data. Each technique hasitsown algorithms.
3.1 RSA Encryption
The RSA algorithm involves three steps: key generation,
encryption and decryption.
Key Generation
1. Two large distinct prime numbers p and q are
chosen at random using primality tests. This
makes factoring harder.
2. Evaluate the modulus n as n = pq and then find
φ(n)
3. Now we choose our public key (say ’e’) such
that 1 < e < φ(n) and gcd(e, φ(n)) = 1 as the
public key exponent.
4. And now for the private key exponent, we find
d such that d = e −1 mod φ(n).
5. Thus we have: The public key consisting of the
modulus n and the public (or encryption)
exponent e. And the private key consists of the
modulus n and the private (or decryption)
exponent d, which must be kept secret. p,q,and
φ(n) must also be kept secret because they can
be used to calculate d.
Encryption
1. Both A and B agree upon a padding scheme
(reversible protocol).
2. A sends his/her public key (n, e) to B but
keeps the private key d a secret.
3. If B now wants to send a message M to A, B
converts the message M into an integer m
using the padding scheme B the computes the
cipher text C as C = Me mod n B then transmits
C to A.
Decryption
1. A recovers the integer M from C as
M=Cd mod n.
2. Given m, A recovers the original message
M by reversing the padding scheme [2].

3.2. DWT Steganography
The proposed architecture deals with the separable 2-D
DWT, whose mathematical formulas are defined as follows
[3]:
Fig–3: DWT steganography model
Where,
.
The two dimensional Discrete Wavelet Transform (DWT) is
an important function in many multimediaapplications,such
as JPEG2000 and MPEG-4 standards, digital watermarking,
and content-based multimedia information retrieval
systems. The 2D DWT is computationally intensive than
other functions, for instance, in the JPEG2000 standard.
Here we are using the two dimensional discrete wavelet
transform.

Fig – 4: Flowchart of the system
To make sure of the data security we must use these
techniques. The original data is taken from the system. This
data is encrypted using RSA encryption then an image is
selected where this encrypted data will be hidden andhence
obtaining a stego object. This stego object is later uploaded
to the cloud sever. Whenever you feel necessity for the file,
the image is downloaded from the cloud and data is
extracted from the image obtaining the original image. The
data is hence decrypted to obtain the original file back for
which again RSA is used for decryption process.
The encrypted data will be in the form of ASCII codes.
Each character in the file is converted to ASCII codes on
encryption. On decryption, again the combination of prime
numbers should be given. If invalid combination of keys is
given then it leads to error and henceforth it provides
security.
4. RESULTS AND DISCUSSION
This project resulted in development of a noble venture to
ensure security in cloud computing. The ’CLOUD DATA
SECURITY’ enables to make sure the security of data. The
main techniques used are encryption and steganography in
which we evaluate and verify data. This ensures multilevel
security mechanisms of the data. Thuscertifyingfortification
of data over cloud computing. This project paved an
opportunity to develop an application which is of use to the
society.
Fig – 5: Comparison between input image and stego-
object
This figure showsthe comparisonof the input image andthe
stego object, where the encrypted data is hidden into.
5. CONCLUSION
Modem area of information technology is fully based on
online service or web services. Our projectdealwithsecurity
problems in cloud computing systems and how they can be
prevented, here we use cryptography and Steganography
method together to secure data. RSA algorithm is more
secure than other algorithm. We integrate RSA algorithm
with other algorithm to provide more security to data. In
Steganography processwe get encryptedimage,whichlooks
exactly the same to original image by human eye. If we
analysis the image binary codes then the differences would
be seen. Otherwise we are unable to identify the original
image. The approach we have use in this paper, will help to
make a strong structure for security of data in cloud
computing field.
REFERENCES
[1] Dr. K.B.Priya Iyer , Manisha R , Subhashree R ,Vedhavalli
K “ANALYSIS OF DATA SECURITY IN CLOUD
COMPUTING” International Conference on Advances in
Electrical, Electronics, Information, Communicationand
Bio-Informatics,2016 IEEE
[2] Nentawe Y. Goshwe Arham Chopra ,“Data Encryption
and Decryption Using RSA Algorithm in a Network
Environment”.
[3] Po-Cheng Wu and Liang-Gee Chen “An Efficient
Architecture for Two-Dimensional Discrete Wavelet
Transform” IEEE TRANSACTIONS ON CIRCUITS AND
SYSTEMS FOR VIDEO TECHNOLOGY, VOL. 11, NO. 4,
APRIL 2001.

IRJET- Enhanced Cloud Data Security using Combined Encryption and Steganography

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