The use of cloud computing has increased rapidly in many organizations. Cloud computing provides many benefits in terms of low cost and accessibility of data. Ensuring the security of cloud computing is a major factor in the cloud computing environment, as users often store sensitive information with cloud storage providers but these providers may be untrusted. Dealing with “single cloud” providers is predicted to become less popular with customers due to risks of service availability failure and the possibility of malicious insiders in the single cloud. A movement towards “multi-clouds”, or in other words, “inter-clouds” or “cloud-of-clouds” has emerged recently. This paper surveys recent research related to single and multi-cloud security and addresses possible solutions. It is found that the research into the use of multi-cloud providers to maintain security has received less attention from the research community than has the use of single clouds. This work aims to promote the use of multi-clouds due to its ability to reduce security risks that affect the cloud computing user. Depsky architecture to implement the multi-cloud system helps to provide “Confidentiality” as well as “Integrity” along with protection to phishing attacks. We propose VCS based scheme to protect the multi-cloud system from phishing attack. In this scheme user can easily detect the phishing sites.

1. ABSTRACT:
The use of cloud computing has increased rapidly in many organizations. Cloud
computing provides many benefits in terms of low cost and accessibility of data.
Ensuring the security of cloud computing is a major factor in the cloud computing
environment, as users often store sensitive information with cloud storage providers
but these providers may be untrusted. Dealing with “single cloud” providers is
predicted to become less popular with customers due to risks of service availability
failure and the possibility of malicious insiders in the single cloud. A movement
towards “multi-clouds”, or in other words, “inter-clouds” or “cloud-of-clouds” has
emerged recently. This paper surveys recent research related to single and multi-
cloud security and addresses possible solutions. It is found that the research into the
use of multi-cloud providers to maintain security has received less attention from
the research community than has the use of single clouds. This work aims to
promote the use of multi-clouds due to its ability to reduce security risks that affect
the cloud computing user.
Depsky architecture to implement the multi-cloud system helps to provide
“Confidentiality” as well as “Integrity” along with protection to phishing attacks.
We propose VCS based scheme to protect the multi-cloud system from phishing
attack. In this scheme user can easily detect the phishing sites.
1. INTRODUCTION:
1.1 BACKGROUND:
NIST [1] describes cloud computing as “a model for enabling convenient, on-
demand network access to a shared pool of configurable computing
resources (e.g., networks, servers, storage, applications, and services) that
can be rapidly provisioned and released with minimal management effort or
service provider interaction”.
In literature of security, to protect from phishing attacks attribute based
schemes are used. But false positive rate of these methods is higher, so we
propose new VCS based anti-phishing framework.
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2. 1.2 AIM AND OBJECTIVE:
The use of cloud computing has increased rapidly in many organizations. Cloud
computing provides many benefits in terms of low cost and accessibility of data.
Ensuring the security of cloud computing is a major factor in the cloud computing
environment, as users often store sensitive information with cloud storage providers
but these providers may be untrusted. Dealing with “single cloud” providers is
predicted to become less popular with customers due to risks of service availability
failure and the possibility of malicious insiders in the single cloud. A movement
towards “multi-clouds”, or in other words, “interclouds” or “cloud-of-clouds” has
emerged recently. This paper surveys recent research related to single and multi-
cloud and addresses possible solutions. It is found that the research into the use of
multi-cloud providers to maintain security has received less attention from the
research community than has the use of single clouds. This work aims to promote
the use of multi-clouds due to its ability to reduce security risks that affect the cloud
computing user.
While making a cloud secure, the following objectives are to be met:
1) Understanding the cloud computing environment provided by the cloud service
provider.
2) The cloud computing solution should meet the basic security and privacy
requirements of any firm deploying it.
3) Maintain an account of the privacy of the cloud and data security and applications
that are deployed in cloud computing environment.
4) Data Integrity.
5) Service Availability.
6) The user runs customer applications using the service provider’s resources
1.2 PROPOSED WORK:
This paper focuses on the issues related to the data security aspect of cloud
computing. As data and information will be shared with a third party, cloud
computing users want to avoid an untrusted cloud provider. Protecting private and
important information, such as credit card details or a patient’s medical records
from attackers or malicious insiders is of critical importance. In addition, the
potential for migration from a single cloud to a multi-cloud environment is
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3. examined and research related to security issues in single and multi-clouds in cloud
Computing are surveyed.
2. PROPOSED SYSTEM:
3.1PROPOSED APPROACH:
In this system we are uploading the file onto the different public cloud
which maintains the integrity confidentiality and security of uploaded
files on cloud. We use MD5 algorithm for computing the hash value
(digital signature) of files before upload. After that we apply our main
algorithm which divides files into different shares and each share
contains unreadable text format and that will be uploaded to each cloud.
At download time we can choose any of the 3 clouds and that file will be
reconstructed.
3.2PROPOSED ARCHITECTURE:
3.2.1 User Registration Process:
3.2.2 User Login Process:
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4. 3.2.3 Multicloud Architecture for Data Security:
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6. 4 Tools/ Software Required:
4.1 Microsoft Visual Studio 2010
4.2 Microsoft SQL Server 2008
4.3 Windows Azure & Other Cloud FTP Accounts
4.4 File Zilla ftp client to view files on cloud spaces.
5 Algorithms Used:
5.1Visual Cryptography Scheme
5.1.1 Share Creation Algorithm
5.1.2 Share Re-Construction Algorithm
5.2 Dynamic Captcha Creation
5.3 MD5
5.4 Shamir’s Secrete Sharing:
5.4.1 Creating Shares
5.4.2 Re-Construction
6 Modules of Project:
6.1 User Registration:
6.1.1 VCS Share Generation
6.1.2 Share Download to User
6.1.3 Saving user login credentials to server
6.2 User Login:
6.2.1 VCS Share Re-Construction
6.2.2 Authenticate User
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7. 6.3 File Upload Module:
6.3.1 Create shares using Shamir’s Secrete Sharing
6.3.2 Calculate MD5 signature for original file
6.3.3 Store log for file-upload
6.3.4 Upload all shares
6.4 File Download:
6.4.1 Shares re-construction
6.4.2 Check for integrity of file
6.4.3 Download if correctly matching MD5 signatures otherwise
warn user regarding malicious content.
6.5 User log:
6.5.1 View User Upload & Download Logs
6.6 Cloud Configuration Module:
6.6.1 Configure login credentials for cloud FTP api for file transfer
on cloud servers.
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8. [5] Amazon, Amazon Web Services. Web services licensing agreement,
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[6] G. Ateniese, R. Burns, R. Curtmola, J. Herring, L. Kissner, Z. Peterson and D. Song,
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