scholarly journals Convertible Authenticated Encryption Scheme with Hierarchical Access Control

2014 ◽  
Vol 8 (3) ◽  
pp. 1239-1246 ◽  
Author(s):  
Chien-Lung Hsu ◽  
Han-Yu Lin
Keyword(s):  
Access Control ◽  
Encryption Scheme ◽  
Authenticated Encryption

Improvement of Tseng et al.'s authenticated encryption scheme with message linkages

2005 ◽  
Vol 162 (3) ◽  
pp. 1475-1483 ◽  
Author(s):  
Zhang Zhang ◽  
Shunsuke Araki ◽  
Guozhen Xiao
Keyword(s):  
Encryption Scheme ◽  
Authenticated Encryption

scholarly journals Cryptanalysis of PMACx, PMAC2x, and SIVx

2017 ◽  
pp. 162-176
Author(s):  
Kazuhiko Minematsu ◽  
Tetsu Iwata
Keyword(s):  
Provable Security ◽  
Block Cipher ◽  
Query Complexity ◽  
Block Length ◽  
Encryption Scheme ◽  
Authenticated Encryption ◽  
Pseudorandom Functions ◽  
Tweakable Block Cipher ◽  
Deterministic Authenticated Encryption ◽  
Provably Secure

At CT-RSA 2017, List and Nandi proposed two variable input length pseudorandom functions (VI-PRFs) called PMACx and PMAC2x, and a deterministic authenticated encryption scheme called SIVx. These schemes use a tweakable block cipher (TBC) as the underlying primitive, and are provably secure up to the query complexity of 2n, where n denotes the block length of the TBC. In this paper, we falsify the provable security claims by presenting concrete attacks. We show that with the query complexity of O(2n/2), i.e., with the birthday complexity, PMACx, PMAC2x, and SIVx are all insecure.

Exploring Type-and-Identity-Based Proxy Re-Encryption Scheme to Securely Manage Personal Health Records

2010 ◽  
Vol 1 (2) ◽  
pp. 1-21
Author(s):  
Luan Ibraimi ◽  
Qiang Tang ◽  
Pieter Hartel ◽  
Willem Jonker
Keyword(s):  
Access Control ◽  
Health Data ◽  
Third Party ◽  
Personal Health ◽  
Encryption Scheme ◽  
Health Records ◽  
Web Based ◽  
The Third ◽  
Access Control Policies ◽  
Identity Based

Commercial Web-based Personal-Health Record (PHR) systems can help patients to share their personal health records (PHRs) anytime from anywhere. PHRs are very sensitive data and an inappropriate disclosure may cause serious problems to an individual. Therefore commercial Web-based PHR systems have to ensure that the patient health data is secured using state-of-the-art mechanisms. In current commercial PHR systems, even though patients have the power to define the access control policy on who can access their data, patients have to trust entirely the access-control manager of the commercial PHR system to properly enforce these policies. Therefore patients hesitate to upload their health data to these systems as the data is processed unencrypted on untrusted platforms. Recent proposals on enforcing access control policies exploit the use of encryption techniques to enforce access control policies. In such systems, information is stored in an encrypted form by the third party and there is no need for an access control manager. This implies that data remains confidential even if the database maintained by the third party is compromised. In this paper we propose a new encryption technique called a type-and-identity-based proxy re-encryption scheme which is suitable to be used in the healthcare setting. The proposed scheme allows users (patients) to securely store their PHRs on commercial Web-based PHRs, and securely share their PHRs with other users (doctors).

An Attribute-Based Searchable Encryption Scheme for Non-Monotonic Access Structure

2020 ◽  
pp. 263-283 ◽  
Author(s):  
Mamta ­ ◽  
Brij B. Gupta
Keyword(s):  
Access Control ◽  
Searchable Encryption ◽  
Access Structure ◽  
Encryption Scheme ◽  
Security Model ◽  
Secret Key ◽  
Fine Grained ◽  
Diffie Hellman ◽  
Attribute Based Encryption ◽  
Encryption Schemes

Attribute based encryption (ABE) is a widely used technique with tremendous application in cloud computing because it provides fine-grained access control capability. Owing to this property, it is emerging as a popular technique in the area of searchable encryption where the fine-grained access control is used to determine the search capabilities of a user. But, in the searchable encryption schemes developed using ABE it is assumed that the access structure is monotonic which contains AND, OR and threshold gates. Many ABE schemes have been developed for non-monotonic access structure which supports NOT gate, but this is the first attempt to develop a searchable encryption scheme for the same. The proposed scheme results in fast search and generates secret key and search token of constant size and also the ciphertext components are quite fewer than the number of attributes involved. The proposed scheme is proven secure against chosen keyword attack (CKA) in selective security model under Decisional Bilinear Diffie-Hellman (DBDH) assumption.

scholarly journals A Pairing-Based Three-Party Authenticated Encryption Scheme without Shared Secrets

Symmetry ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 605
Author(s):  
Han-Yu Lin
Keyword(s):  
Computational Efficiency ◽  
Encryption Scheme ◽  
Authenticated Encryption ◽  
Random Oracles ◽  
Comparison Results ◽  
Communication Environments ◽  
Single User ◽  
Designated Verifier

The Traditional Authenticated Encryption (AE) scheme is a single-user cryptographic mechanism which only enables one designated verifier to authenticate the ciphertext. Although several group-oriented AE variants have also been proposed to eliminate such a limitation, they require shared verification. This motivated us to think of a scenario of three-party communication environments where each party runs independent processes without cooperation. In this paper, we realize a novel three-party AE (abbreviated to TPAE) scheme in which two designated verifiers can solely decrypt the same ciphertext and then inspect the validity of embedded signature. Additionally, we also show that our TPAE construction is computationally secure using the well-defined IND-CCA2 and the EF-CMA adversary games in the proof model of random oracles. The comparison results will demonstrate the computational efficiency of our mechanism.

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