Attribute-based Proxy Re-encryption Scheme Research Articles

A Verifiable and Fair Attribute-Based Proxy Re-Encryption Scheme for Data Sharing in Clouds

To manage outsourced encrypted data sharing in clouds, attribute-based proxy re-encryption (ABPRE) has become an elegant primitive. In ABPRE, a cloud server can transform an original recipient’s ciphertext to a new one of a shared user’s. As the transformation is computation consuming, a malicious cloud server may return an incorrect re-encrypted ciphertext to save its computation resources. Moreover, a shared user may accuse the cloud server of returning an incorrect re-encrypted ciphertext to refuse to pay the cost of using the cloud service. However, existing ABPRE schemes do not support a mechanism to achieve verifiability and fairness. In this article, a novel verifiable and fair attribute-based proxy re-encryption (VF-ABPRE) scheme is introduced to support verifiability and fairness. The verifiability enables a shared user to verify whether the re-encrypted ciphertext returned by the server is correct and the fairness ensures a cloud server escape from malicious accusation if it has indeed conducted the re-encryption operation honestly. Additionally, we conduct a performance experiment to show the efficiency and practicality of the new VF-ABPRE scheme.

A Ring Learning with Errors-Based Ciphertext-Policy Attribute-Based Proxy Re-Encryption Scheme for Secure Big Data Sharing in Cloud Environment.

Owing to the huge volume of big data, users generally use the cloud to store big data. However, because the data are out of the control of users, sensitive data need to be protected. The ciphertext-policy attribute-based encryption scheme can not only effectively control the access of big data, but also decrypt the ciphertext as long as the user's attributes satisfy the access structure of ciphertext, so as to realize one to many big data sharing. When the user's attributes do not satisfy the access structure of ciphertext, the attribute-based proxy re-encryption scheme can be used for big data sharing. The ciphertext-policy attribute-based proxy re-encryption (CP-ABPRE) scheme combines the characteristics of the ciphertext-policy attribute-based encryption scheme and proxy re-encryption scheme. In a CP-ABPRE scheme, on the one hand, the data owner can use the ciphertext-policy attribute-based encryption scheme to encrypt the big data for cloud storage, to realize the access control of the big data. On the other hand, the proxy (cloud service provider) can convert ciphertext under one access structure into ciphertext under another access structure, thus realizing big data sharing between users of different attribute sets. In this article, we modify the existing attribute-based encryption scheme based on Ring Learning With Errors (RLWE), add re-encryption key generation algorithm, re-encryption ciphertext generation algorithm, and re-encryption ciphertext decryption algorithm, and construct CP-ABPRE scheme. In the construction of the re-encryption key, we introduce a random vector and hide the vector in the key by threshold technology. Finally, a CP-ABPRE scheme supporting threshold access structure is constructed based on RLWE. Compared with the existing attribute-based proxy re-encryption schemes, our scheme has smaller public parameters, can encrypt multiple plaintext bits at a time, and can resist selective access structure and chosen plaintext attack, so it is more suitable for big data sharing in cloud environment.

A CCA-secure key-policy attribute-based proxy re-encryption in the adaptive corruption model for dropbox data sharing system

The notion of attribute-based proxy re-encryption extends the traditional proxy re-encryption to the attribute-based setting. In an attribute-based proxy re-encryption scheme, the proxy can convert a ciphertext under one access policy to another ciphertext under a new access policy without revealing the underlying plaintext. Attribute-based proxy re-encryption has been widely used in many applications, such as personal health record and cloud data sharing systems. In this work, we propose the notion of key-policy attribute-based proxy re-encryption, which supports any monotonic access structures on users’ keys. Furthermore, our scheme is proved against chosen-ciphertext attack secure in the adaptive model.

Sharing your privileges securely: a key-insulated attribute based proxy re-encryption scheme for IoT

Attribute based proxy re-encryption (ABPRE) combines the merits of proxy re-encryption and attribute based encryption, which allows a delegator to re-encrypt the ciphertext according to the delegatees’ attributes. The theoretical foundations of ABPRE has been well studied, yet to date there are still issues in schemes of ABPRE, among which time-bounded security and key exposure protection for the re-encryption keys are the most concerning ones. Within the current ABPRE framework, the re-encryption keys are generated independently of the system time segments and the forward security protection is not guaranteed when the users’ access privileges are altered. In this paper, we present a key-insulated ABPRE scheme for IoT scenario. We realize secure and fine-grained data sharing by utilizing attribute based encryption over the encrypted data, as well as adopting key-insulation mechanism to provide forward security for re-encryption keys and private keys of users. In particular, the lifetime of the system is divided into several time slices, and when system enters into a new slice, the user’s private keys need are required to be refreshed. Therefore, the users’ access privileges in our system are time-bounded, and both re-encryption keys and private keys can be protected, which will enhance the security level during data re-encryption, especially in situations when key exposure or privilege alternation happens. Our scheme is proved to be secure under MDBDH hardness assumptions as well as against collusion attack. In addition, the public parameters do not have to be changed during the evolution of users’ private keys, which will require less computation resources brought by parameter synchronization in IoT.

Efficient and Adaptively Secure Attribute-Based Proxy Reencryption Scheme

Ciphertext-Policy Attribute-Based Proxy Reencryption (CP-ABPRE) has found many practical applications in the real world, because it extends the traditional Proxy Reencryption (PRE) and allows a semitrusted proxy to transform a ciphertext under an access policy to the one with the same plaintext under another access policy. The existing CP-ABPRE schemes were proven secure only in the selective security model, a limited model, which is an unnatural constraint on the attacker. The scheme proved in this model can only be called selectively secure one. However, from a security perspective, the adaptively secure CP-ABPRE scheme is more desirable. In this paper, an adaptively secure CP-ABPRE scheme is proposed, which is based on Waters’ dual system encryption technology. The proposed scheme is constructed in composite order bilinear groups and proven secure under the complexity assumptions of the subgroup decision problem for 3 primes (3P-SDP). Analyses show that our proposal provides higher computational efficiency compared with the existing schemes.

A Study of Attribute-Based Proxy Re-Encryption Scheme in Cloud Environments

Attribute-based proxy re-encryption (ABPRE) scheme is one of the proxy cryptography, which can delegate the re-encryption capability to the proxy and re-encrypt the encrypted data by using the re-encryption key. ABPRE ex-tending the traditional proxy cryptography and attributes plays an important role. In ABPRE, users are identified by attributes, and the access policy is designed to control the user's access. Using ABPRE can have these advantages: (i) The proxy can be delegated to execute the re-encryption operation, which reduces the computation overhead of the data owner;(ii) The authorized user just uses his own secret key to decrypt the encrypted data, and he doesn't need to store an additional decryption key for deciphering;(iii) The sensitive information cannot be revealed to the proxy in re-encryption, and the proxy only complies to the data owner's command. In this paper, we survey two various access policy attribute-based proxy re-encryption schemes and analyze these schemes. Thereafter, we list the comparisons of them by some criteria.

Attribute-based re-encryption scheme in the standard model

In this paper, we propose a new attribute-based proxy re-encryption scheme, where a semi-trusted proxy, with some additional information, can transform a ciphertext under a set of attributes into a new ciphertext under another set of attributes on the same message, but not vice versa, furthermore, its security was proved in the standard model based on decisional bilinear Diffie-Hellman assumption. This scheme can be used to realize fine-grained selectively sharing of encrypted data, but the general proxy re-encryption scheme severely can not do it, so the proposed scheme can be thought as an improvement of general traditional proxy re-encryption scheme.