Declustering techniques for parallelizing temporal access structures

One of the main open problems in secret sharing is the characterization of the ideal access structures. This problem has been studied for several families of access structures with similar results. Namely, in all these families, the ideal access structures coincide with the vector space ones and, besides, the optimal information rate of a non-ideal access structure is at most $2/3$. An access structure is said to be $r$-homogeneous if there are exactly $r$ participants in every minimal qualified subset. A first approach to the characterization of the ideal $3$-homogeneous access structures is made in this paper. We show that the results in the previously studied families can not be directly generalized to this one. Nevertheless, we prove that the equivalences above apply to the family of the sparse $3$-homogeneous access structures, that is, those in which any subset of four participants contains at most two minimal qualified subsets. Besides, we give a complete description of the ideal sparse $3$-homogeneous access structures.

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A New Black and White Visual Cryptographic Scheme for General Access Structures

Progress in Cryptology - INDOCRYPT 2004 - Lecture Notes in Computer Science ◽

10.1007/978-3-540-30556-9_31 ◽

2004 ◽

pp. 399-413 ◽

Cited By ~ 18

Author(s):

Avishek Adhikari ◽

Tridib Kumar Dutta ◽

Bimal Roy

Keyword(s):

Black And White ◽

Access Structures ◽

Cryptographic Scheme

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Efficient Attribute-Based Data Sharing Scheme with Hidden Access Structures

The Computer Journal ◽

10.1093/comjnl/bxz052 ◽

2019 ◽

Vol 62 (12) ◽

pp. 1748-1760 ◽

Cited By ~ 2

Author(s):

Yang Chen ◽

Wenmin Li ◽

Fei Gao ◽

Wei Yin ◽

Kaitai Liang ◽

...

Keyword(s):

Access Control ◽

Data Sharing ◽

Inner Product ◽

Access Structure ◽

Online Data ◽

Fine Grained ◽

Access Structures ◽

Attribute Based Encryption ◽

And Performance ◽

Ciphertext Policy

AbstractOnline data sharing has become a research hotspot while cloud computing is getting more and more popular. As a promising encryption technique to guarantee the security shared data and to realize flexible fine-grained access control, ciphertext-policy attribute-based encryption (CP-ABE) has drawn wide attentions. However, there is a drawback preventing CP-ABE from being applied to cloud applications. In CP-ABE, the access structure is included in the ciphertext, and it may disclose user’s privacy. In this paper, we find a more efficient method to connect ABE with inner product encryption and adopt several techniques to ensure the expressiveness of access structure, the efficiency and security of our scheme. We are the first to present a secure, efficient fine-grained access control scheme with hidden access structure, the access structure can be expressed as AND-gates on multi-valued attributes with wildcard. We conceal the entire attribute instead of only its values in the access structure. Besides, our scheme has obvious advantages in efficiency compared with related schemes. Our scheme can make data sharing secure and efficient, which can be verified from the analysis of security and performance.

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