ABSTRACT:
Cloud storage services have become
increasingly popular. Because of the importance of privacy, many cloud storage
encryption schemes have been proposed to protect data from those who do not
have access. All such schemes assumed that cloud storage providers are safe and
cannot be hacked; however, in practice, some authorities (i.e., coercers) may
force cloud storage providers to reveal user secrets or confidential data on
the cloud, thus altogether circumventing storage encryption schemes. In this
paper, we present our design for a new cloud storage encryption scheme that
enables cloud storage providers to create convincing fake user secrets to
protect user privacy. Since coercers cannot tell if obtained secrets are true
or not, the cloud storage providers ensure that user privacy is still securely
protected.
EXISTING
SYSTEM:
·
There are numerous ABE schemes that have been proposed. Most of the
proposed schemes assume cloud storage service providers or trusted third
parties handling key management are trusted and cannot be hacked; however, in
practice, some entities may intercept communications between users and cloud
storage providers and then compel storage providers to release user secrets by
using government power or other means. In this case, encrypted data are assumed
to be known and storage providers are requested to release user secrets.
·
Sahai and Waters first introduced the concept of ABE in which data
owners can embed how they want to share data in terms of encryption.
·
There are two types of ABE, CP-ABE and Key-Policy ABE (KP-ABE). Goyal et
al. proposed the first KPABE. They constructed an expressive way to relate any
monotonic formula as the policy for user secret keys. Bethencourt et al.
proposed the first CP-ABE. This scheme used a tree access structure to express
any monotonic formula over attributes as the policy in the ciphertext.
DISADVANTAGES OF EXISTING SYSTEM:
·
It is also impractical to encrypt data many times for many people. With
ABE, data owners decide only which kind of users can access their encrypted
data. Users who satisfy the conditions are able to decrypt the encrypted data.
·
Use translucent sets or simulatable public key systems to implement
deniability.
·
Most deniable public key schemes are bitwise, which means these schemes
can only process one bit a time; therefore, bitwise deniable encryption schemes
are inefficient for real use, especially in the cloud storage service case.
·
Most of the previous deniable encryption schemes are inter-encryption
independent. That is, the encryption parameters should be totally different for
each encryption operation. If two deniable encryptions are performed in the
same environment, the latter encryption will lose deniability after the first
encryption is coerced, because each coercion will reduce flexibility.
·
Most deniable encryption schemes have decryption error problems. These
errors come from the designed decryption mechanisms.
PROPOSED SYSTEM:
·
In this work, we describe a deniable ABE scheme for cloud storage
services. We make use of ABE characteristics for securing stored data with a
fine-grained access control mechanism and deniable encryption to prevent
outside auditing. Our scheme is based on Waters ciphertext policy-attribute
based encryption (CP-ABE) scheme. We enhance the Waters scheme from prime order
bilinear groups to composite order bilinear groups. By the subgroup decision
problem assumption, our scheme enables users to be able to provide fake secrets
that seem legitimate to outside coercers.
·
In this work, we construct a deniable CP-ABE scheme that can make cloud
storage services secure and auditfree. In this scenario, cloud storage service
providers are just regarded as receivers in other deniable schemes.
ADVANTAGES OF PROPOSED SYSTEM:
·
Unlike most previous deniable encryption schemes, we do not use
translucent sets or simulatable public key systems to implement deniability.
Instead, we adopt the idea proposed with some improvements. We construct our
deniable encryption scheme through a multidimensional space. All data are
encrypted into the multidimensional space.
·
Only with the correct composition of dimensions is the original data
obtainable. With false composition, ciphertexts will be decrypted to
predetermined fake data. The information defining the dimensions is kept
secret. We make use of composite order bilinear groups to construct the
multidimensional space. We also use chameleon hash functions to make both true
and fake messages convincing.
·
In this work, we build a consistent environment for our deniable
encryption scheme. By consistent environment, we means that one encryption
environment can be used for multiple encryption times without system updates.
The opened receiver proof should look convincing for all ciphertexts under this
environment, regardless of whether a cipher text is normally encrypted or
deniably encrypted. The deniability of our scheme comes from the secret of the
subgroup assignment, which is determined only once in the system setup phase.
By the canceling property and the proper subgroup assignment, we can construct
the released fake key to decrypt normal ciphertexts correctly.
SYSTEM REQUIREMENTS:
HARDWARE REQUIREMENTS:
·
System : Pentium IV 2.4 GHz.
·
Hard Disk : 40 GB.
·
Floppy Drive : 44 Mb.
·
Monitor : 15 VGA Colour.
·
Mouse :
·
Ram : 512 Mb.
SOFTWARE REQUIREMENTS:
·
Operating system : Windows XP/7.
·
Coding Language : JAVA/J2EE
·
IDE : Netbeans 7.4
·
Database : MYSQL
REFERENCE:
Po-Wen Chi and
Chin-Laung Lei, Member, IEEE, “Audit-Free Cloud Storage via Deniable
Attribute-based Encryption”, IEEE Transactions
on Cloud Computing, 2015.