Secure Out sourced Attribute-based Signatures

Secure Out sourced Attribute-based Signatures

ABSTRACT:

Attribute-based signature (ABS) enables users to sign messages over attributes without revealing any information other than the fact that they have attested to the messages. However, heavy computational cost is required during signing in existing work of ABS, which grows linearly with the size of the predicate formula. As a result, this presents a significant challenge for resource-constrained devices (such as mobile devices or RFID tags) to perform such heavy computations independently.Aiming at tackling the challenge above, we first propose and formalize a new paradigm called Outsourced ABS, i.e., OABS, in which the computational overhead at user side is greatly reduced through outsourcing intensive computations to an untrustedsigning-cloud service provider (S-CSP). Furthermore, we apply this novel paradigm to existing ABS schemes to reduce the complexity. As a result, we present two concrete OABS schemes: i) in the first OABS scheme, the number of exponentiations involving in signing is reduced from O(d) to O(1) (nearly three), where d is the upper bound of threshold value defined in the predicate; ii) our second scheme is built on Herranz et al.’s construction with constant-size signatures. The number of exponentiations in signing is reduced from O(d2 ) to O(d) and the communication overhead is O(1). Security analysis demonstrates that both OABS schemes are secure in terms of the unforgeability and attribute-signer privacy definitions specified in the proposed security model. Finally, to allow for high efficiency and flexibility, we discuss extensions of OABS and show how to achieve accountability as well.

EXISTING SYSTEM:

Cloud computing has plenty of benefits for the real-world applications such as on-demand self-service, ubiquitous network access, location independent resource pooling, rapid resource elasticity, usage-based pricing, and outsourcing etc. In the outsourcing computation paradigm, the users with resource-constraint devices can outsource the heavy computation workloads into the cloud server and enjoy the unlimited computing resources in a pay-per-use manner. Though promising as it is, this paradigm also brings forth some new challenges when users intend to outsource ABS on an untrusted cloud server. Specifically, since some private information is involved in the outsourced signing operation, it demands a way to prevent the untrusted S-CSP from learning any private information of the signer.

DISADVANTAGES OF EXISTING SYSTEM:

1)    Cloud service provider once the signature is not generated correctly.

2)    ABS is that the time required to sign grows with the complexity of predicate formula.

3)    The generation of signature requires a large number of module exponentiations, which commonly grows linearly with the size of the predicate formula.

PROPOSED SYSTEM:

In this paper, aiming at reducing the computational overhead at signer side, we propose two efficient outsourced ABS (OABS) schemes denoted by OABS-I and OABS-II. We employ a hybrid private key by introducing a default attribute for all the users in the system. More precisely, an AND gate is involved to bound two sub-components of the user private key: i) the private key component for user’s attributes (denoted as outsourcing key OK in this paper) which is to be utilized by S-CSP to compute the outsourced signature; ii) the private key component for the default attribute which is to be utilized by signer to generate a normal ABS signature from the outsourced signature returned from S-CSP. The security of the both schemes can be guaranteed based on the observation that outsourcing key is restricted by the user. In this way, S-CSP can only sign the specified message on behalf of user.

ADVANTAGES OF PROPOSED SYSTEM:

1)    Our technique provides a feasible way to realize the “piecewise key generation.

2)    To allow for high efficiency and flexibility.

SYSTEM REQUIREMENTS:

HARDWARE REQUIREMENTS:

Ø System                          :         Pentium IV 2.4 GHz.

Ø Hard Disk                      :         40 GB.

Ø Floppy Drive                 :         1.44 Mb.

Ø Monitor                         :         15 VGA Colour.

Ø Mouse                            :         Logitech.

Ø Ram                               :         512 Mb.

SOFTWARE REQUIREMENTS:

Ø Operating system           :         Windows XP/7.

Ø Coding Language :         JAVA/J2EE

Ø IDE                      :         Netbeans 7.4

Ø Database              :         MYSQL

REFERENCE:

Xiaofeng Chen, Jin Li, Xinyi Huang, Jingwei Li, Yang Xiang, and Duncan S. Wong “Secure Outsourced Attribute-based Signatures” DOI 10.1109/TPDS.2013.2295809, IEEE Transactions on Parallel and Distributed Systems, 2014.