An Efficient Cloud-Based Revocable Identity-Based Proxy Re-encryption Scheme for Public Clouds Data Sharing

Abstract

Identity-based encryption (IBE) eliminates the necessity of having a costly certificate verification process. However, revocation remains as a daunting task in terms of ciphertext update and key update phases. In this paper, we provide an affirmative solution to solve the efficiency problem incurred by revocation. We propose the first cloud-based revocable identity-based proxy re-encryption (CR-IB-PRE) scheme that supports user revocation but also delegation of decryption rights. No matter a user is revoked or not, at the end of a given time period the cloud acting as a proxy will re-encrypt all ciphertexts of the user under the current time period to the next time period. If the user is revoked in the forthcoming time period, he cannot decrypt the ciphertexts by using the expired private key anymore. Comparing to some naive solutions which require a private key generator (PKG) to interact with non-revoked users in each time period, the new scheme provides definite advantages in terms of communication and computation efficiency

Security of Cloud-Based Revocable Identity-Based Proxy Re-Encryption Scheme

“…In this paper, we showed that the CR-IB-PRE scheme [4] is vulnerable to collusion attacks whereby a non-revoked user's private key is revealed. How to construct the CR-IB-PRE scheme with a constant number of private key and update key elements remains an open problem.…”

“…The security model of CR-IB-PRE was introduced by Liang et al [4]. In this security model, the update token query takes as input identity ID and time T .…”

“…This implies that the system needs to enable a designated party who is given the right to update the ciphertext by the key generation center. Recently, Liang et al [4] proposed a cloudbased revocable identity-based proxy re-encryption (CR-IB- PRE) scheme. This scheme allows only a valid administrator to update the ciphertext with a re-encryption key for the new time period.…”

Revocable-Storage Identity-Based Encryption In Cloud Computing For Secure Data Sharing

“…Subsequently, by using the aforementioned revocation technique, Libertand Vergnaud [9] proposed an adaptively secure RIBE scheme based on a variant of Water's IBE scheme [10] Chenet al [11]. Constructed an RIBE scheme, from lattices.…”

Collusion-Resistant Identity-Based Proxy Re-Encryption Without Random Oracles

“…In PRE scheme, the proxy does not know the secret key of Alice or Bob, and also does not know the plaintext during the conversion. PRE schemes have many applications such as digital rights management (DRM), distributed storage, encrypted email forwarding, and law enforcement [1][2][3][4][5].…”