scholarly journals Revocable attribute-based proxy re-encryption

2021 ◽  
Vol 15 (1) ◽  
pp. 465-482
Author(s):  
Fucai Luo ◽  
Saif Al-Kuwari
Keyword(s):  
Cloud Storage ◽  
Security Model ◽  
Encrypted Data ◽  
Practical Applications ◽  
Access Policy ◽  
Attribute Based Encryption ◽  
The Standard Model ◽  
Identity Based ◽  
Learning With Errors ◽  
Predicate Encryption

Abstract Attribute-based proxy re-encryption (ABPRE), which combines the notions of proxy re-encryption (PRE) and attribute-based encryption (ABE), allows a semi-trusted proxy with re-encryption key to transform a ciphertext under a particular access policy into a ciphertext under another access policy, without revealing any information about the underlying plaintext. This primitive is very useful in applications where encrypted data need to be stored in untrusted environments, such as cloud storage. In many practical applications, and in order to address scenarios where users misbehave or the re-encryption keys are compromised, an efficient revocation mechanism is necessary for ABPRE. Previously, revocation mechanism was considered in the settings of identity-based encryption (IBE), ABE, predicate encryption (PE), and broadcast PRE, but not ABPRE, which is what we set to do in this paper. We first formalize the concept of revocable ABPRE and its security model. Then, we propose a lattice-based instantiation of revocable ABPRE. Our scheme not only supports an efficient revocation mechanism but also supports polynomial-depth policy circuits and has short private keys, where the size of the keys is dependent only on the depth of the supported policy circuits. In addition, we prove that our scheme is selectively chosen-plaintext attack (CPA) secure in the standard model, based on the learning with errors assumption.

scholarly journals Server-Aided Revocable Predicate Encryption: Formalization and Lattice-Based Instantiation

2019 ◽  
Vol 62 (12) ◽  
pp. 1849-1862
Author(s):  
San Ling ◽  
Khoa Nguyen ◽  
Huaxiong Wang ◽  
Juanyang Zhang
Keyword(s):  
Third Party ◽  
Fine Grained ◽  
Attribute Based Encryption ◽  
The Standard Model ◽  
User Revocation ◽  
Promising Solution ◽  
Identity Based ◽  
Role Based ◽  
Predicate Encryption ◽  
Learning With Errors Problem

Abstract Efficient user revocation is a necessary but challenging problem in many multi-user cryptosystems. Among known approaches, server-aided revocation yields a promising solution, because it allows to outsource the major workloads of system users to a computationally powerful third party, called the server, whose only requirement is to carry out the computations correctly. Such a revocation mechanism was considered in the settings of identity-based encryption and attribute-based encryption by Qin et al. (2015, ESORICS) and Cui et al. (2016, ESORICS ), respectively. In this work, we consider the server-aided revocation mechanism in the more elaborate setting of predicate encryption (PE). The latter, introduced by Katz et al. (2008, EUROCRYPT), provides fine-grained and role-based access to encrypted data and can be viewed as a generalization of identity-based and attribute-based encryption. Our contribution is 2-fold. First, we formalize the model of server-aided revocable PE (SR-PE), with rigorous definitions and security notions. Our model can be seen as a non-trivial adaptation of Cui et al.’s work into the PE context. Second, we put forward a lattice-based instantiation of SR-PE. The scheme employs the PE scheme of Agrawal et al. (2011, ASIACRYPT) and the complete subtree method of Naor et al. (2001, CRYPTO) as the two main ingredients, which work smoothly together thanks to a few additional techniques. Our scheme is proven secure in the standard model (in a selective manner), based on the hardness of the learning with errors problem.

scholarly journals Server-Aided Revocable Attribute-Based Encryption from Lattices

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Xingting Dong ◽  
Yanhua Zhang ◽  
Baocang Wang ◽  
Jiangshan Chen
Keyword(s):  
Access Control ◽  
Standard Model ◽  
Secret Key ◽  
Bilinear Maps ◽  
Encrypted Data ◽  
Fine Grained ◽  
Attribute Based Encryption ◽  
The Standard Model ◽  
Learning With Errors

Attribute-based encryption (ABE) can support a fine-grained access control to encrypted data. When the user’s secret-key is compromised, the ABE system has to revoke its decryption privileges to prevent the leakage of encrypted data. Although there are many constructions about revocable ABE from bilinear maps, the situation with lattice-based constructions is less satisfactory, and a few efforts were made to close this gap. In this work, we propose the first lattice-based server-aided revocable attribute-based encryption (SR-ABE) scheme and thus the first such construction that is believed to be quantum resistant. In the standard model, our scheme is proved to be secure based on the hardness of the Learning With Errors (LWE) problem.

scholarly journals Towards Virtuous Cloud Data Storage Using Access Policy Hiding in Ciphertext Policy Attribute-Based Encryption

2021 ◽  
Vol 13 (11) ◽  
pp. 279
Author(s):  
Siti Dhalila Mohd Satar ◽  
Masnida Hussin ◽  
Zurina Mohd Hanapi ◽  
Mohamad Afendee Mohamed
Keyword(s):  
Data Storage ◽  
Cloud Storage ◽  
Security Analysis ◽  
Data Access ◽  
Logical Connective ◽  
Encrypted Data ◽  
Cloud Data ◽  
Access Policy ◽  
Attribute Based Encryption ◽  
Ciphertext Policy

Managing and controlling access to the tremendous data in Cloud storage is very challenging. Due to various entities engaged in the Cloud environment, there is a high possibility of data tampering. Cloud encryption is being employed to control data access while securing Cloud data. The encrypted data are sent to Cloud storage with an access policy defined by the data owner. Only authorized users can decrypt the encrypted data. However, the access policy of the encrypted data is in readable form, which results in privacy leakage. To address this issue, we proposed a reinforcement hiding in access policy over Cloud storage by enhancing the Ciphertext Policy Attribute-based Encryption (CP-ABE) algorithm. Besides the encryption process, the reinforced CP-ABE used logical connective operations to hide the attribute value of data in the access policy. These attributes were converted into scrambled data along with a ciphertext form that provides a better unreadability feature. It means that a two-level concealed tactic is employed to secure data from any unauthorized access during a data transaction. Experimental results revealed that our reinforced CP-ABE had a low computational overhead and consumed low storage costs. Furthermore, a case study on security analysis shows that our approach is secure against a passive attack such as traffic analysis.

scholarly journals Accounting and Privacy Preserving of Data Owner in Cloud Storage

2021 ◽  
Vol 10 (6) ◽  
pp. 14-17
Author(s):  
Mohan A. ◽  
vamshikrishna P.
Keyword(s):  
Distributed Computing ◽  
Cloud Storage ◽  
Cloud Provider ◽  
Confidential Information ◽  
Encrypted Data ◽  
Access Policy ◽  
Attribute Based Encryption ◽  
Data Owner ◽  
Edos Attacks ◽  
Ciphertext Policy

People use the support of distributed computing however can't completely believe the cloud suppliers to have protection and confidential information. To guarantee secrecy, data owners relocate encoded information rather than plain texts. To divide the encoded documents with different clients, Ciphertext-Policy Attribute-based Encryption (CP-ABE) can be utilized. But this cannot become secure against some other assaults. Many other schemes did not gave guarantee that the cloud provider has the power to check whether a downloader can unscramble or not. Consequently, these files are accessible to everybody who is approachable to the cloud storage. An intentionally harmful assailant can download a great many records to start Economic Denial of Sustainability (EDoS) attacks, it will to a great extent expend the cloud asset. The owner will bear all the expenses for the cloud storage but the cloud provider doesn’t provide the whole information about the access or usage. There is no transparency for the owner. We have to solve these concerns. In order to this we are going to propose a solution for securing the encrypted data from EDoS attacks and providing the owner whole usage information about the cloud storage. We are implementing by using the arbitrary access policy of CP-ABE.

scholarly journals Ciphertext-Policy Attribute-based Encryption with Hidden Sensitive Policy for Recruitment in Smart City

2020 ◽  
Author(s):  
Fei Meng ◽  
Leixiao Cheng ◽  
Mingqiang Wang
Keyword(s):  
Smart City ◽  
End Users ◽  
The Other ◽  
Sensitive Information ◽  
Security Model ◽  
Access Policy ◽  
Computational Overhead ◽  
Attribute Based Encryption ◽  
Ciphertext Policy ◽  
Access Policies

Abstract Smart city, as a promising technical tendency, greatly facilitates citizens and generates innumerable data, some of which is very private and sensitive. To protect data from unauthorized users, ciphertext-policy attribute-based encryption (CP-ABE) enables data owner to specify an access policy on encrypted data. However, There are two drawbacks in traditional CP-ABE schemes. On the one hand, the access policy is revealed in the ciphertext so that sensitive information contained in the policy is exposed to anyone who obtains the ciphertext. For example, both the plaintext and access policy of an encrypted recruitment may reveal the company's future development plan. On the other hand, the decryption time scales linearly with the complexity of the access, which makes it unsuitable for resource-limited end users. In this paper, we propose a CP-ABE scheme with hidden sensitive policy for recruitment in smart city. Specifically, we introduce a new security model chosen sensitive policy security: two access policies embedded in the ciphertext, one is public and the other is sensitive and fully hidden, only if user's attributes satisfy the public policy, it's possible for him/her to learn about the hidden policy, otherwise he/she cannot get any information (attribute name and its values) of it. When the user satisfies both access policies, he/she can obtain and decrypt the ciphertext. Compared with other CP-ABE schemes, our scheme supports a more expressive access policy, since the access policy of their schemes only work on the ``AND-gate'' structure. In addition, intelligent devices spread all over the smart city, so partial computational overhead of encryption of our scheme can be outsourced to these devices as fog nodes, while most part overhead in the decryption process is outsourced to the cloud. Therefore, our scheme is more applicable to end users with resource-constrained mobile devices. We prove our scheme to be selective secure under the decisional bilinear Diffie-Hellman (DBDH) assumption.

CCA-Secure and Revocable Certificateless Encryption with Ciphertext Evolution

2020 ◽  
Vol 31 (02) ◽  
pp. 175-191
Author(s):  
Yinxia Sun ◽  
Futai Zhang ◽  
Anmin Fu ◽  
Zhe Xia
Keyword(s):  
Security Requirements ◽  
User Needs ◽  
Security Model ◽  
Encrypted Data ◽  
Public Key Cryptosystems ◽  
Generic Construction ◽  
Certificateless Encryption ◽  
User Revocation ◽  
Identity Based ◽  
Certificate Management

Certificateless cryptosystems have attracted great interests in cryptographic research since its invention. Because compared with traditional public key cryptosystems or identity-based cryptosystems, they could not only simplify the certificate management, but also alleviate the key escrow problem. In certificateless cryptosystems, user revocation is a challenging issue. To address this issue, one popular method is to update the key via public channels. However, most of the existing schemes in this approach are impractical because of the following two shortcomings. Firstly, the user needs to maintain a list of decryption keys, but the size of the list will keep increasing. Secondly, the revoked user can still recover the plaintexts of the encrypted data prior to revocation, and this is a particular threat in some applications. To solve these problems, this paper presents revocable certificateless encryption with ciphertext evolution. We give a generic construction and then describe how it can be initialized concretely. In our proposed scheme, the user only needs to keep one decryption key, and once a user is revoked, it can no longer decrypt any ciphertext in the server. Moreover, the IND-CCA security model is defined against three types of attacks. And our schemes are formally proved to satisfy these security requirements.

scholarly journals Light Weight Cryptography based Medical Data and Image Encryption Scheme

Webology ◽  
2021 ◽  
Vol 18 (2) ◽  
pp. 88-104
Author(s):  
M. Raja ◽  
Dr.S. Dhanasekaran ◽  
Dr.V. Vasudevan
Keyword(s):  
Data Privacy ◽  
Medical Information ◽  
Security Analysis ◽  
Encrypted Data ◽  
Attribute Based Encryption ◽  
Identity Based ◽  
Information Confidentiality ◽  
Processing And Storage ◽  
And Storage ◽  
Maintenance Problem

Many medical companies use cloud technology to collect, distribute and transmit medical records. Given the need for medical information, confidentiality is a key issue. In this study, we propose an encrypted scheme based on encrypted data for an electronic healthcare environment. We use hybrid Attribute based encryption and Triple DES encryption technique (ABETDES) scheme, including identity-based cryptography (IBC), to ensure data privacy through communication channels և to improve the reliability of cloud computing. There are also limited indicators of light processing and storage resources. This solves a serious maintenance problem and ensures that a private key is created where it is not blind. The introduction of a security option, a comprehensive security analysis to protect ciphertext, shows that our program is effective against many known attacks and compared to existing methods.

SECURITY ANALYSIS OF A FUZZY IDENTITY-BASED ENCRYPTION SCHEME

2014 ◽  
Vol 23 (03) ◽  
pp. 1450033 ◽  
Author(s):  
MIAOMIAO TIAN ◽  
LIUSHENG HUANG ◽  
WEI YANG
Keyword(s):  
Security Analysis ◽  
Error Tolerance ◽  
Encryption Scheme ◽  
Security Model ◽  
Private Key ◽  
Identity Based Encryption ◽  
The Standard Model ◽  
Real World Applications ◽  
Identity Based ◽  
Fuzzy Identity

Fuzzy identity-based encryption (FIBE) scheme is a kind of identity-based encryption (IBE) scheme, in which any user's identity is composed by a set of attributes and any ciphertext encrypted under identity ID can be decrypted by using a private key corresponding to identity ID′ if ID′ is close to ID as measured by some metric. Due to the error-tolerance property, FIBE scheme is very useful in real-world applications. However, most FIBE schemes are provable secure only in a weaker security model. In order to eliminate this problem, Ren et al. recently proposed a new FIBE scheme and proved that it is fully chosen-ciphertext secure in the standard model. Unfortunately, in this paper, we will show that their FIBE scheme is even not chosen-plaintext secure.

scholarly journals Space-Efficient Key-Policy Attribute-Based Encryption from Lattices and Two-Dimensional Attributes

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Yuan Liu ◽  
Licheng Wang ◽  
Xiaoying Shen ◽  
Lixiang Li ◽  
Dezhi An
Keyword(s):  
Secret Sharing ◽  
Secret Key ◽  
Security Issue ◽  
Access Policy ◽  
Attribute Based Encryption ◽  
The Standard Model ◽  
Security Problem ◽  
Key Policy ◽  
Space Cost ◽  
Dynamic Updating

Linear secret-sharing scheme (LSSS) is a useful tool for supporting flexible access policy in building attribute-based encryption (ABE) schemes. But in lattice-based ABE constructions, there is a subtle security problem in the sense that careless usage of LSSS-based secret sharing over vectors would lead to the leakage of the master secret key. In this paper, we propose a new method that employs LSSS to build lattice-based key-policy attribute-based encryption (KP-ABE) that resolves this security issue. More specifically, no adversary can reconstruct the master secret key since we introduce a new trapdoor generation algorithm to generate a strong trapdoor (instead of a lattice basis), that is, the master secret key, and remove the dependency of the master secret key on the total number of system attributes. Meanwhile, with the purpose of reducing the storage cost and support dynamic updating on attributes, we extended the traditional 1-dimensional attribute structure to 2-dimensional one. This makes our construction remarkably efficient in space cost, with acceptable time cost. Finally, our scheme is proved to be secure in the standard model.

scholarly journals Secure Outsourced Medical Data against Unexpected Leakage with Flexible Access Control in a Cloud Storage System

2020 ◽  
Vol 2020 ◽  
pp. 1-20
Author(s):  
Xingguang Zhou ◽  
Jianwei Liu ◽  
Zongyang Zhang ◽  
Qianhong Wu
Keyword(s):  
Access Control ◽  
Medical Records ◽  
Cloud Storage ◽  
Storage System ◽  
Role Based Access Control ◽  
Security Model ◽  
Access Policy ◽  
Fine Grained ◽  
Privacy Leakage ◽  
Role Based

The application of cloud storage system has been deployed widely in recent years. A lot of electronic medical records (EMRs) are collected and uploaded to the cloud for scalable sharing among the authority users. It is necessary to guarantee the confidentiality of EMRs and the privacy of EMR owners. To achieve this target, we summarize a series of attack behaviors in the cloud storage system and present the security model against many types of unexpected privacy leakage. Privacy of unassailed EMRs is guaranteed in this model, and the influence of privacy leakage is controlled in a certain scope. We also propose a role-based access control scheme to achieve flexible access control on these private EMRs. One can access medical records only if his/her role satisfies the defined access policy, which implies a fine-grained access control. Theoretical and experimental analyses show the efficiency of our scheme in terms of computation and communication.

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