The primary issue to be dealt with when talking about security in a cloud is protection of the data. The main purpose is to build up a privacy preserving repository where data sharing services can update and control the access and limit the usage of their shared data, instead of submitting data to central authorities, and, hence, the shared-disk database architecture will promote data sharing and privacy of data.

1. “PRIVACY PRESERVING REPOSITORY FOR SOCIAL
NETWORKING APPLICATION ACROSS CLOUD”
P. R. PATIL COLLEGE OF ENGINEERING AND TECHNOLOGY
DEPARTMENT OF COMPUTER SCIENCE
SESSION-2014-15
Presented by Guided by
Ms. Pritam V. Kilor Prof. V. B. Bhagat

2. CONTENTS
 Introduction
 Literature Review
 Proposed Method
 Conclusion and Future Work

3. INTRODUCTION
 Privacy is an important issue in cloud computing,
With the development of internet technology,
privacy preserving data publication has become
one of the most important research topics
Security has been a serious issue of concern in
the cloud.

4. SERVICES ON CLOUD
 Infrastructure as a Service(IAAS)
 Software as a Service(SAAS)
 Platform as a Service(PAAS)

5. MOTIVATION
The following are some of the major issues related
to security
• Server Access Security
• Database Access Security
• Internet Access Security
• Program Access Security
• Data Privacy Security
Of the above mentioned security issues we are
focusing on the data privacy security issue.

6. AIM AND SCOPE
Repository is beneficial in the
following ways:
 The data sharing services in the cloud possess
the ability to update and control the access and
usages of their shared data.
 The sharing of data in the cloud is done based on the
need-to-share principle.
 The repository is limited to gathering data from data
sharing services and combining the data to satisfy
user’s requirements.

7. LITERATURE REVIEW
Bertino and Ferrari describe mechanisms for fine-
grained encryption of parts of XML documents.
Hippocratic databases include mechanisms for
preserving the privacy of the data they manage.
Their proposed architecture is based on the concept
of associating privacy metadata

8. IBM Tivoli Privacy Manage provided mechanisms for
defining fine grained privacy policies and associating
them with data.
This approach addressed the privacy management
problem purely from an access control perspective
within a single enterprise.

9.  Stephen S. Yau, gives a concept about warehouse
for integrating data from various data sharing
services
warehouse Central authorities
collects data from data sharing
services based on users‘
integration requirements
Collects all the data from the data
sharing services
capability of warehouse is
controlled to computing the
integration results required by
users
central establishment have full control
of the collected data
only reveal the results of the
specified data integration demand
Central establishment will reveal all
data

10. RC6 ALGORITHM
 RC6 is an evolutionary improvement of RC5, designed
to meet the requirements of the Advanced Encryption
Standard (AES)
 A version of RC6 is more accurately specified as RC6-
w/r/b
 The plaintext, is stored in four w-bit input registers called
(A,B,C,D). Keys are being stored into an array S[0,...,2r
+ 3].

11.  Features of RC6 include the use of four working registers
instead of two.
 Decryption works in a similar way as encryption, the
difference is that cipher text is the input and plaintext is
the output.

12. PROPOSED METHOD
 The social networking applications have become very
popular and commonly used by the users in the modern
times.
 The objectives of propose project work to preserve the
privacy of the data while it is being shared by the user to
the friends.
 The sharing of the data can be done need-based.

13. OBJECTIVE OF PROPOSED SYSTEM:
 To preserve the privacy of user’s file using RC6
algorithm.
 To provide sharing of encrypted files among various
groups.
 To provide need based sharing by using TTL.
 To provide security to the files from accessing by
unauthorized user

14. Flow diagram for uploading files on repository

15. FLOW DIAGRAM FOR FILES SHARING BETWEEN USER AND
GROUPS

16. The current dissertation work is divided
into following phases:
 Database creation
 Login / Signup Module
 File Upload/Download Module
 Creation of Groups/Joining Groups
 File sharing between user and groups
 Result evaluation and optimization of system

17. SNAPSHOTS:
Login form

18. SNAPSHOTS
Creation of group

19. SNAPSHOTS
joining of group

20. SNAPSHOTS
Uploading of files

21. SNAPSHOTS
File sharing

22. SNAPSHOTS
Download file

23. SNAPSHOTS
Group request

24. RESULT ANALYSIS
 Here we have calculated encryption time for
different file size using RC6.
 Comparison of RC6 with AES and Twofish w.r.t.
encryption time for 16-bytes key.
File Name (file
type )
File Size
(KB)
Encryption time
withRC6algo.
(in ms)
Encryption time with
AES algo.(in ms)[25]
Encryption time
withTwofishalgo.(in
ms)[25]
A.doc 712 85.912 232.5 229.65
B.pdf 649 77.746 205 214.625
C.jpg 656 75.763 224.5 232.75

25. CONCLUSION AND FUTURE WORK
 Here we are trying to give an assurance to the clients
that their data is secured in cloud server with the help of
RC6 algorithm, and privacy of data is also maintained
 Future research along this topic includes how to extend
the expressiveness of specification language, enable
repository to support more types of data integration
operations.

26. References
1) Cong Wang, Sherman S.M. Chow, Qian Wang, KuiRen, and Wenjing Lou
“Privacy-Preserving Public Auditing for Secure Cloud Storage”, IEEE
Transactions On Computers, Vol. 62, No. 2, pp. 362 – 375, February 2013.
2) Yuan, Jiawei, and Shucheng Yu. "Privacy Preserving Back-Propagation Neural
Network Learning Made Practical with Cloud Computing", IEEE Transactions on
Parallel and Distributed Systems, Vol. 25, Issue 1, pp. 212 – 221, 2014.
3) Ranjita Mishra and Sanjit Kumar Dash,A Privacy Preserving Repository for
Securing Data across the Cloud ―IEEE 978-1-4244-8679, 2011
4) Gurudayal Singh Bhandari, Abhishek Chauhan, “A Survey on Privacy
Preservation in Cloud Computing ,” International Journal of Emerging Technology
and Advanced Engineering” Volume 4, Issue 7, July 2014 ,pp.710-723
.5) Shrinivas, D. "Privacy-Preserving Public Auditing In Cloud Storage Security."
International Journal of computer science and Information Technologies,ISSN:
0975-9646, vol. 2, no. 6, pp. 2691-2693

27. Thank You