In the cloud era people get used to store their data to the cloud server, and would use encryption technique to protect their sensitive data from leakage. However, encrypted data management is a challenging problem, for example, encrypted data classification. Besides, how to effectively control the access to the encrypted data is also an important problem. Ciphertext-policy attribute-based encryption with equality test (CP-ABEET) is an efficient solution to the aforementioned problems, which enjoys the advantage of attribute-based encryption, and in the meanwhile supports the test of whether two different ciphertexts contain the same message without the need of decryption. However, the existing CP-ABEET schemes suffer from high computation costs. In this paper, we study how to outsource the heavy computation in CP-ABEET scheme to a third-party server. We introduce the notion of CP-ABEET supporting outsourced decryption (OCP-ABEET), which saves a lot of local computation loads of CP-ABEET. We propose a concrete construction of OCP-ABEET, and prove its security based on a reasonable number-theoretic assumption in the random oracle model. Compared with the existing CP-ABEET schemes, our scheme is more computationally .

Outsourced Ciphertext-Policy Attribute-Based Encryption with Equality Test

Sensitive data would be encrypted before uploading to the cloud due to the privacy issue. However, how to compare the encrypted data efficiently becomes a problem. Public Key Encryption with Equality Test (PKEET) provides an efficient way to check whether two ciphertexts (of possibly different users) contain the same message without decryption. As an enhanced variant, Attribute-based Encryption with Equality Test (ABEET) provides a flexible mechanism of authorization on the equality test. Most of the existing ABEET schemes are only proved to be secure in the random oracle model. Their security, however, would not be guaranteed if random oracles are replaced with real-life hash functions. In this work, we propose a construction of CP-ABEET scheme and prove its security based on some reasonable assumptions in the standard model. We then show how to modify the scheme to outsource complex computations in decryption and equality test to a third-party server in order to support thin clients.

/pdf/attribute-based-equality-test-over-encrypted-data-without-p5k2bzjogg.pdf

Attribute-Based Equality Test Over Encrypted Data Without Random Oracles

Fog computing is increasingly popular partly due to its capability to minimize data transfer and latency requirements, for example by moving some of the computational operations away from the cloud servers and closer to the users. To achieve fine-grained access control in fog-enabled application scenarios to guarantee data security and user privacy, one could use ciphertext-policy attribute-based encryption (CP-ABE). However, the lack of an effective mechanism to carry out access right revocation in conventional CP-ABE schemes limits the deployment of such schemes in practice. Thus, we propose an efficient CP-ABE scheme with attribute revocation capability, designed to construct a fine-grained access control system in fog-enabled E-health (referred to as AC-FEH). In our AC-FEH system, fog nodes undertake data encryption and decryption operations; thus, computational costs for data owners and users are minimized. In comparison to several other competing access control schemes based on CP-ABE, our AC-FEH system reduces the computational costs associated with encryption and decryption. We also prove the selective security of the underlying CP-ABE scheme under the intractability assumption of the $q$ -parallel BDHE problem.

/pdf/an-efficient-access-control-scheme-with-outsourcing-and-1fnl2mcyp8.pdf

An Efficient Access Control Scheme With Outsourcing and Attribute Revocation for Fog-Enabled E-Health

The quality of health care delivery is declining with the high cost of health services. This is as a result of the delay in obtaining necessary health information from patients and/or ineffective management of health information. To avert this, a new paradigm called e-health, which fuses wearable medical devices or non-invasive measuring devices with cloud computing has been adopted to improve health care delivery. This allows medical centers and health carers to function more competently and also for patients to obtain better treatments. The adoption of wearable medical devices and cloud computing provides easy and instant access to a large volume of health information. However, it introduces some information management bottlenecks, security, and privacy challenges. In this paper, we propose a security scheme that provides effective health information management and secure access to patients’ health information in an e-health system. The approach also supports cooperative health care delivery among carers through effective information sharing techniques. A two-layer security approach is adopted using the symmetric key and modified ciphertext-policy attribute-based encryption to provide fine-grained access control, time-based attribute revocation, and cooperative health service delegation among carers. Also, fog devices are adopted to create hierarchical storage for effective health information management.

FEACS: A fog enhanced expressible access control scheme with secure services delegation among carers in E-health systems

Due to the massive growth of data and security concerns, data of patients would be encrypted and outsourced to the cloud server for feature matching in various medical scenarios, such as personal health record systems, actuarial judgments and diagnostic related groups. Public key encryption with equality test (PKEET) is a useful utility for encrypted feature matching. Authorized tester could perform data matching on encrypted data without decrypting. Unfortunately, due to the limited terminology in medicine, people within institutions may illegally use data, trying to obtain information through traversal methods. In this paper we propose a new PKEET notion, called public-key authenticated encryption with designated equality test (PKAE-DET), which could resist this kind of attacks launched by an inside adversary, known as offline message recovery attacks (OMRA). We propose a concrete construction of PKAE-DET, which only requires one single server to perform the feature matching job securely, and does not require any group mechanism. We prove its security based on some simple mathematical assumptions. Experimental results show that our scheme has efficiency comparable with those PKEET schemes which do not resist OMRA attacks or require group mechanism. We further show how our scheme could be effectively used in diagnostic related groups in medicine, demonstrating its practicability.

/pdf/public-key-authenticated-encryption-with-designated-equality-1pl96wsct7.pdf

Public Key Authenticated Encryption With Designated Equality Test and its Applications in Diagnostic Related Groups

Ciphertext-Policy Attribute-Based Encrypted Data Equality Test and Classification


 Thanks to the ease of access and low expenses, it is now popular for people to store data in cloud servers. To protect sensitive data from being leaked to the outside, people usually encrypt the data in the cloud. However, management of these encrypted data becomes a challenging problem, e.g. data classification. Besides, how to selectively share data with other users is also an important and interesting problem in cloud storage. In this paper, we focus on ciphertext-policy attribute based encryption with equality test (CP-ABEET). People can use CP-ABEET to implement not only flexible authorization for the access to encrypted data, but also efficient data label classification, i.e. test of whether two encrypted data contain the same message. We construct an efficient CP-ABEET scheme, and prove its security based on a reasonable number-theoretic assumption. Compared with the only existing CP-ABEET scheme, our construction is more efficient in key generation, and has shorter attribute-related secret keys and better security.

/pdf/ciphertext-policy-attribute-based-encrypted-data-equality-3h8g4sbr98.pdf

Jianye Huang

Papers

Ciphertext-Policy Attribute-Based Encrypted Data Equality Test and Classification

Outsourced Ciphertext-Policy Attribute-Based Encryption with Equality Test

Ciphertext-Policy Attribute-Based Encrypted Data Equality Test and Classification.