Securing the digital landscape is paramount in our interconnected world. This abstract delves into the fundamentals of cyber security, exploring its vital role in safeguarding individuals, organizations, and nations against the pervasive threat of cybercrime. It examines the evolving challenges posed by cyber threats, from sophisticated attacks to emerging vulnerabilities, while elucidating practical strategies to mitigate risks and fortify defenses. Through an exploration of cybercrime's multifaceted nature, coupled with insights into the latest antivirus and firewall technologies, this abstract equips readers with essential knowledge to navigate the digital realm safely and responsibly. In today's interconnected world, the protection of digital assets is paramount. This abstract serves as a deep dive into the foundational principles and advanced strategies of cyber security, illuminating its indispensable role in safeguarding individuals, organizations, and nations against the ever-looming specter of cybercrime. Beginning with an exploration of cyber security's core tenets, including confidentiality, integrity, and availability, readers are introduced to the fundamental principles that underpin effective defense strategies. Through insightful analysis and real-world examples, the abstract highlights the critical importance of maintaining these principles in the face of evolving cyber threats.

1. DYNAMIC HASH TABLE BASED
PUBLIC AUDITING FOR SECURE
CLOUD STORAGE
Md junaid ali
syed junaid ali
Md ibaduddin
7 semester B.Tech CSE, Department of Computer Science,
GNDEC BIDAR
NATIONAL CONFERENCE
NCSTEM-2024
PRESENTED BY:

2. OUTLINE OF THE PRESENTATION
o OBJECTIVE
o INTRODUCTION
o EXISTING METHOD
o PROBLEM DESCRIPTION
o BLOCK DIAGRAM
o PROPOSED METHOD
o APPLICATIONS
o EXECUTION TOOLS
o CONCLUSION

3. OBJECTIVE
 The objective of the system is to develop a system
that would enable the cloud users to have control
over their data so that they can ensure that their
data is secured and not corrupted.
 It provides security to the users data by encrypting
the data and splitting up the file into small blocks for
storage.
 Auditing the cloud storage without demanding a
local copy of data enables more efficiency.

4. INTRODUCTION
 Cloud computing customers do not own a physical
infrastructure; rather they rent the usage from a third
party provider.
 They consume resources as a service and pay only for
resources that they use.
 Cloud computing comes in three forms: public clouds,
private clouds, and hybrids clouds.
 Public clouds offer the greatest level of efficiency in
shared resources but are more vulnerable.
 Private clouds offer the greatest level of security and
control, but they require the company to still purchase
and maintain all the software and infrastructure.
 Hybrid cloud includes both public and private
options.The downside is that we have to keep track of
multiple different security platforms.

5.  Cloud computing provides on demand self
services,location independent resource
pooling,rapid resource elasticity,usage based
pricing etc..
 Challenge faced is security threats towards users
outsourced data.
 Here the correctness of user data in the cloud is put
at risk.
 CSP might reclaim storage for monetary reasons by
discarding rarely accesed data or even hiding data
corruption due to server hacks over byzantine
failures.

6. MAC
key
File block
code
Message Authentication Code (MAC)
Block 1 Block n
Block 2 …
File is divided into blocks
Cloud
user
TPA
Block 1 Block n
…
Block 2
code 1 code n
…
code 2
-User computes the MAC of every file block
-Transfers the file blocks & codes to cloud
-Shares the key with TPA
Audit
-TPA demands a random number of
blocks and their code from CSP
-TPA uses the key to verify the
correctness of the file blocks
Drawbacks: -The audit demands retrieval of user’s data; this is not privacy-preserving
-Communication and computation complexity are linear with the sample size
EXISTING METHOD
BASIC SCHEME 1

7. BASIC SCHEME 2
Block 1 Block n
…
Block 2
code 1 code n
…
code 2
code 1 code n
…
code 2
code 1 code n
…
code 2
Key 1
Key s
Key 2
…
user
Cloud
TPA
Block 1 Block m
…
Block 2
Setup
-User uses s keys and computes the MAC for blocks
-User shares the keys and MACs with TPA
Audit
-TPA gives a key (one of the s keys) to CSP and requests MACs for the blocks
-TPA compares with the MACs at the TPA
-Improvement from Scheme 1: TPA doesn’t see the data, preserves privacy
-Drawback: a key can be used once.
-The TPA has to keep a state; remembering which key has been used
-Schemes 1 & 2 are good for static data (data doesn’t change at the cloud)

8. PROBLEM DESCRIPTION
 Audit cloud storage demanding local copy of data.
 Violates the privacy-preserving guarantee.
 Large communication overhead and time delay.
 Band-width available between the TPA and the
cloud server is limited.
 Auditor can modify user data.
 Copy of user data on auditing side.
 No data control on user side.
 The number of times a particular data file can be
audited is limited by the number of secret key.

9. BLOCK DIAGRAM
U: cloud user has a large amount of data files to store in the cloud
CS: cloud server which is managed by the CSP and has significant
data storage and computing power (CS and CSP are the same in
this paper)
TPA: third party auditor has expertise and capabilities that U and
CSP don’t have. TPA is trusted to assess the CSP’s storage security
upon request from U

10. Setup & audit phases of public auditing scheme.

11.  Consists of four algorithms (KeyGen, SigGen,
GenProof, VerifyProof)
 KeyGen: key generation algorithm that is run by
the user
 SigGen: used by the user to generate verification
metadata, which may consist of MAC, signatures or
other information used for auditing
 GenProof: run by the cloud server to generate a
proof of data storage correctness
 VerifyProof: run by the TPA to audit the proof
from the cloud server

12. PROPOSED METHOD
 Public auditing scheme which provides a complete
outsourcing solution of data– not only the data
itself, but also its integrity checking
 System consist of client and server side application
and website.
 Effectively audit cloud storage without demanding
local copy of data.
 Extensive security and performance analysis shows
provably secure and highly efficient.
 Data conrtol in the hands of users only.

13. Flow chart:

14. APPLICATIONS
 Used in applications that require public auditing.
 Can be used for batch auditing.
 Application that ensures storage correctness.

15. Constraints
 Only the registered users will be authorized to use the
service.
 A trustworthy TPA is required to audit the storage.
Assumptions and dependencies
 The project will not change in scope
 The resources identified will be available upon request
 Approved funding will be available upon request
 Only the registered users can access the Website
 Roles and tasks are predefined.

16. EXECUTION TOOLS
Hardware Requirements
 Intel Pentium dual core processor or above
 1 GB RAM
 200 GB HDD
 Other standard peripherals
Software Requirements
 Operating system : windows XP
 Tool: Netbeans IDE 6.1
 Programming Package : Jdk.5.0
 Database :MySQL
 Server :Glassfish v2

17. CONCLUSION
 The aim of the project is to develop a system that
would enable the cloud users to have control over
their data so that they can ensure that their data is
secured .
 They can know whether there is any data loss or
corruption by logging into the website.
 TPA would not learn any knowledge about the
data content stored on the cloud server during the
efficient auditing process.
 TPA can perform multiple auditing tasks in a batch
manner for better efficiency.
 Schemes are provably secure and highly efficient.

18. Final output