2. Abstract
Data sharing is an important functionality in
cloud storage.
In this paper, we show how to securely,
efficiently, and flexibly share data with others
in cloud storage.
We describe new public-key cryptosystems that
produce constant-size cipher texts such that
efficient delegations of decryption rights for
any set of cipher texts are possible.
3. Existing System
A cryptographic solution, with proven security
relied on number-theoretic assumptions is more
desirable, whenever the user is not perfectly
happy with trusting the security of the VM or
the honesty of the technical staff.
These users are motivated to encrypt their data
with their own keys before uploading them to
the server.
4. Disadvantage
The costs and complexities involved generally
increase with the number of the decryption
keys to be shared.
The encryption key and decryption key are
different in publickey encryption.
5. Proposed System
In this paper, we study how to make a decryption key
more powerful in the sense that it allows decryption
of multiple ciphertexts, without increasing its size.
Specifically, our problem statement is
“To design an efficient public-key encryption scheme
which supports flexible delegation in the sense that
any subset of the ciphertexts (produced by the
encryption scheme) is decry ptable by a constant-size
decryption key (generated by the owner of the master-
secret key).”
6. Proposed System
We solve this problem by introducing a special
type of public-key encryption which we call
key-aggregate cryptosystem (KAC).
8. Literature Survey
Analysis and Security based on Attribute based Encryption for
data Sharing (ISSN: 2278-9359 (Volume-3, Issue-3)
Ciphertext policy attribute based encryption with efficient
revocation
Cryptosystem for Secure Data Sharing in Cloud Storage (2014
IJIRT , Volume 1 Issue 6 , ISSN: 2349-6002)
9. 1.Analysis and Security based on Attribute based
Encryption for data Sharing
The key-policy attribute are used for describing
encrypting data and policy implemented in user`s key,
and the cipher text policy is the access structure on the
cipher text. And the access structure can also be present
in either monotonic or non-monotonic.
10. 2.Ciphertext policy attribute based
encryption with efficient revocation
Ciphertext Policy Attribute Based Encryption
(CPABE) enables users’ encryption with an
accessstructure while assigning decryption
capability in accordance with attribute sets.
In this paper, we study central-control
revocation in CPABE environment, where the
proposed key generation, encryption and
decryption algorithms closely comply with
CPABE model
11. 3.Cryptosystem for Secure Data
Sharing in Cloud Storage
To achieve a secure and dependable cloud storage
service, a secure multi-owner data sharing scheme is
proposed according to any user in the group so that they
can securely share data with others users by the un-
trusted cloud.
12. Modules
1. Authentication And Authorization
2. File Encryption by KAC
3. Cloud data sharing
4. File Decryption by KAC
13. Authentication And Authorization
Authentication and Authorization process are the required of
the Verifying the User Originality and Appropriate Session
Activities of the Registered User.
14. File Encryption by KAC
After user login, the user can able to store the files into the cloud
in an encryption manner. So that the encrypted files which are
stored in the cloud cannot be decrypted normally by other users
or hacker’s.
15. Cloud data sharing:
The user initially upload’s files data to the cloud, and
shares it with other users. The shared files are encrypted
by the owner. So whenever the other user’s want to
access or decrypt the file required keys permission to be
accessed.
16. File Decryption by KAC:
The aggregate keys are sent in mail to other user by the
original user. The file will be decrypted by the aggregate
key’s which was generated by the KAC.
Finally, any user with an aggregate key can decrypt any
cipher text provided that the cipher text’s class is
contained in the aggregate key via Decrypt.
17. Hardware Reqirements
SYSTEM : Pentium Dual-Core CPU
E5400 2.70GHZ
HARD DISK : 40 GB
MONITOR : 15 VGA colour
MOUSE : Logitech.
RAM : 2 GB
KEYBOARD : 110 keys enhanced.
18. Software Reqirements
Operating system : Windows 8
Coding Language : Java
Front End : Java Server Page
Front End Tool : Net beans 7.0 IDE
Back End DB : mysql
Database GUI : Sqlyog.
19. Conclusion
With more mathematical tools, cryptographic schemes are
getting more versatile and often involve multiple keys for a
single application.
In this project, we proposed KAC and how to “compress”
secret keys in public-key cryptosystems which support
delegation of secret keys for different cipher text classes in
cloud storage.
No matter which one among the power set of classes, the
delegatee can always get an aggregate key of constant size.
Our approach is more flexible than hierarchical key
assignment which can only save spaces if all key-holders share
a similar set of privileges.
