Fully Secure Self-Updatable Encryption in Prime Order Bilinear Groups

Datta, Pratish; Dutta, Ratna; Mukhopadhyay, Sourav

doi:10.1007/978-3-319-13257-0_1

Cited by 3 publications

(2 citation statements)

References 16 publications

(50 reference statements)

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“…Note that this scheme has O(log T max ) group elements in public parameters whereas the scheme of Lee et al [14] in prime-order groups has O(T max ) group elements in public parameters. Independent of our work, Datta et al [8] proposed a fully-secure SUE scheme under standard assumptions.…”

Section: Discussionmentioning

confidence: 99%

Self-updatable encryption with short public parameters and its extensions

Lee

2015

Des. Codes Cryptogr.

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Cloud storage is very popular since it has many advantages, but there is a new threat to cloud storage that was not considered before. Self-updatable encryption that updates a past ciphertext to a future ciphertext by using a public key is a new cryptographic primitive introduced by Lee, Choi, Lee, Park, and Yung (Asiacrypt 2013) to defeat this threat, in which an adversary who obtained a past private key can still decrypt a (previously unread) past ciphertext stored in cloud storage. Additionally, an SUE scheme can be combined with an attribute-based encryption (ABE) scheme to construct a powerful revocable-storage ABE (RS-ABE) scheme introduced by Sahai, Seyalioglu, and Waters (Crypto 2012) that provides the key revocation and ciphertext updating functionality for cloud storage. In this paper, we propose an efficient SUE scheme and its extended schemes. First, we propose an SUE scheme with short public parameters in prime-order bilinear groups and prove its security under a q-type assumption. Next, we extend our SUE scheme to a time-interval SUE (TI-SUE) scheme that supports a time interval in ciphertexts. Our TI-SUE scheme has short public parameters and it is also secure under the q-type assumption. Finally, we propose the first large universe RS-ABE scheme with short public parameters in prime-order bilinear groups and prove its security in the selective revocation list model under a q-type assumption.

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Section: Discussionmentioning

confidence: 99%

Self-updatable encryption with short public parameters and its extensions

Lee

2015

Des. Codes Cryptogr.

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“…Lee et al [22] introduced the notion of SUE and proposed an efficient SUE scheme with CPA security by modifying a hierarchical identity-based encryption (HIBE) scheme [5] to apply the design strategy of forward-secure encryption (FSE) [10]. Then, a number of different SUE schemes were proposed in [14,21]. The main application of SUE is RS-ABE for cloud storage [22].…”

Section: Related Workmentioning

confidence: 99%

CCA Security for Self-Updatable Encryption: Protecting Cloud Data When Clients Read/Write Ciphertexts

Lee

Park

et al. 2018

The Computer Journal

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Self-updatable encryption (SUE) is a new kind of public-key encryption, motivated by cloud computing, which enables anyone (i.e. cloud server with no access to private keys) to update a past ciphertext to a future ciphertext by using a public key. The main applications of SUE is revocable-storage attributebased encryption (RS-ABE) that provides an efficient and secure access control to encrypted data stored in cloud storage. In this setting, there is a new threat such that a revoked user still can access past ciphertexts given to him by a storage server. RS-ABE solves this problem by combining user revocation and ciphertext updating functionalities. The mechanism was designed with semantic security (CPA). Here, we propose the first SUE and RS-ABE schemes, secure against a relevant form of chosenciphertext security (CCA). Due to the fact that some ciphertexts are easily derived from others, we employ a different notion of CCA which avoids easy challenge related messages. Specifically, we define "time extended challenge" (TEC) CCA security for SUE which excludes ciphertexts that are easily derived from the challenge (over time periods) from being queried on (namely, once a challenge is decided by an adversary, no easy modification of this challenge to future and past time periods is allowed to be queried upon). We then propose an efficient SUE scheme with such CCA security, and we also define similar CCA security for RS-ABE and present an RS-ABE scheme with this CCA security.

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