ATTRIBUTE BASED ENCRYPTION WITH PRIVACY PRESERVING IN
CLOUDS
ABSTRACT
Security and privacy are very important issues in cloud computing. In existing
system access control in clouds are centralized in nature. The scheme uses a symmetric
key approach and does not support authentication. Symmetric key algorithm uses same
key for both encryption and decryption. The authors take a centralized approach where a
single key distribution center (KDC) distributes secret keys and attributes to all users. A
new decentralized access control scheme for secure data storage in clouds that supports
anonymous authentication. The validity of the user who stores the data is also verified.
The proposed scheme is resilient to replay attacks. In this scheme using Secure Hash
algorithm for authentication purpose, SHA is the one of several cryptographic hash
functions, most often used to verify that a file has been unaltered. The Paillier crypto
system, is a probabilistic asymmetric algorithm for public key cryptography. Pailier
algorithm use for Creation of access policy, file accessing and file restoring process.
EXISTING SYSTEM
Most existing public key encryption methods allow a party to encrypt data to a
particular user, but are unable to efficiently handle more expressive types of encrypted
access control.
PROPOSED SYSTEM
We proposed a privacy-preserving decentralized Key Distribution Center(KDC)
scheme to protect the user’s privacy. In our scheme, all the user’s secret keys are tied to
his identifier to resist the collusion attacks while the multiple authorities cannot know
anything about the user’s identifier. Notably, each authority can join or leave the system
freely without the need of reinitializing the system and there is no central authority.
Furthermore, any access structure can be expressed in our scheme using the access tree
technique. Finally, our scheme relies on the standard complexity assumption, rather than
the non-standard complexity assumptions.
MODULE :
1. Attribute-based Encryption
2. Cryptography
3. Encryption And Decryption
MODULE DESCRIPTION :
1. Attribute Based Encryption
Global Setup → It takes as input a security parameter and outputs the system parameters
params.
Authority Setup → Each authority generates his secret-public key pair and an access
structure.
KeyGen → Each authority takes as input his secret key, a global identifier and a set of
attributes and outputs the secret.
Encryption → It takes as input the system parameters params, a message and a set of
attributes and outputs the ciphertext.
Decryption → It takes as input the global identifier, the secret keys and the ciphertext
and outputs the message.
2. Cryptography
The art of protecting information by transforming it (encrypting it) into an
unreadable format, called cipher text. Only those who possess a secret key can decipher
(or decrypt) the message into plain text. Encrypted messages can sometimes be broken by
cryptanalysis, also called code breaking, although modern cryptography techniques are
virtually unbreakable.
3. Encryption and Decryption
Encryption: In an encryption scheme, the message or information (referred to as
plaintext) is encrypted using an encryption algorithm, turning it into an unreadable cipher
text (ibid.). This is usually done with the use of an encryption key, which specifies how
the message is to be encoded. Any adversary that can see the cipher text, should not be
able to determine anything about the original message.
Decryption: An authorized party, however, is able to decode the ciphertext using
a decryption algorithm, that usually requires a secret decryption key, that adversaries do
not have access to. For technical reasons, an encryption scheme usually needs a keygeneration algorithm, to randomly produce keys.
SYSTEM ARCHITECTURE :
SYSTEM SPECIFICATION :
Hardware Requirements:
•
System
: Pentium IV 2.4 GHz.
•
Hard Disk
: 40 GB.
•
Floppy Drive
: 1.44 Mb.
•
Monitor
: 14’ Colour Monitor.
•
Mouse
: Optical Mouse.
•
Ram
: 512 Mb.
Software Requirements:
•
Operating system
: Windows 7.
•
Coding Language
: ASP.Net with C#
•
Data Base
: SQL Server 2008.