PDF | Outsourced decryption ABE system largely reduces the computation cost for users who intend to access the encrypted files stored in. Request PDF on ResearchGate | Attribute-Based Encryption With Verifiable Outsourced Decryption | Attribute-based encryption (ABE) is a public-key-based. , IRJET | Impact Factor value: | ISO Certified Journal | Page Attribute-Based Encryption with Verifiable Outsourced Decryption.

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If the adversary has a nonnegligible advantage inthen we can find an algorithm which attacks the scheme [ 33 ] at encryptioh nonnegligible advantage.

Security and Communication Networks. Let be the challenger with respect to of the scheme [ 33 ]. The challenger runs and and stores the entry in table.

Verifiable Outsourced Decryption of Attribute-Based Encryption with Constant Ciphertext Length

Given a ciphertext and a transformation key, CSP transforms a ciphertext into a simple ciphertext. Otherwise, it runs and and stores the tuple in table Tb.

A encyrption generates his transformation key pair as follows.

In this article, we propose a new verifiable outsourced CP-ABE scheme veriifable constant ciphertext length and, moreover, we prove that our scheme is secure and verifiable in standard model. The adversary adaptively issues queries. It then sends the private key to the adversary. We run our code on a PC with bit 2. Bilinear Pairing Definition 1 bilinear map.

Briefly speaking, a user interacts with the CSP as illustrated in Figure 1.

As the amount of verifiabpe files stored in cloud is becoming very huge, searchable encryption scheme over encrypted cloud data is a very challenging issue. The advantage for is defined as.


However, the size of private key, ciphertext, and transform key in [ 111231 ] depends upon the number of attributes.

An encryptor randomly selects. Note that according to assumption. However, the correctness of the transformation ciphertext cannot be guaranteed because the user does not have attribute-basev original ciphertext.

We introduce some basic knowledge about bilinear groups, security assumption, access structure, and CP-ABE which our scheme relies on. Our Motivations and Contributions. However, the ciphertext length and the amount of expensive pairing computations grow with the number of the attributes, which greatly limits its application in power constrained and bandwidth limited devices. Here, we compute as follows: Data owner encrypts message into ciphertext and uploads it to the storage in cloud.

Security and Communication Networks

Suppose is a generator in. View at Google Scholar Z. Our scheme is verifiable which decryptiion that the user efficiently checks whether the transformation is done correctly by the CSP. Therefore, our scheme is very efficient. So we can conclude that if can attack our scheme at nonnegligible advantage, then we will find an algorithm which attacks Basic CP-ABE scheme under the selective CPA security model at nonnegligible advantage.

Security Assumption Definition 2 discrete logarithm DL assumption [ 31 ].

attirbute-based The identity represented by an attribute set is not unique so ABE can realize the one-to-many encryption. TA selectscomputes andand sends to a user associated with attribute set.

Note that ifappropriately simulates ; else, appropriately simulates. The adversary gives a guess for and succeeds in the game if. Access Structure Access structure is being referred to in [ 33 ]; we utilize AND gates with respect to multivalued attributes as follows.


Though its advantages make it a powerful tool for cloud, one of its main performance challenges is that the complexity of decryption computation is linearly correlated with the access structure. We can find that the ciphertext length in our scheme is constant, while it will grow with the amount of attributes involved in access policy linearly.

In essence, the second and the third elements are redundant information. The elliptic curve parameter we choose is type-A, and the order of group is bits.

HKU Scholars Hub: Offline/online attribute-based encryption with verifiable outsourced decryption

We also give the security definitions used in our paper in this section. To protect data privacy, the sensitive data should be encrypted by the data owner prior to outsourcing.

Encruptionlet be an attribute set for a user, and ; let be an access structure.

If such a tuple exists, it sends the transformation key to. Without loss of generality, we suppose that the adversary does not launch transformation key query for attribute setif a private key query about the same attribute set has been issued.

Given the transformation key, the CSP transforms an ABE ciphertext into a simple ciphertext, from which the user recovers plaintext by using less computation overhead. With the cloud service being more and qttribute-based popular in modern society, ABE technology has become a promising orientation.

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