Concealing complex policies with hidden credentials

Bradshaw, Robert W.; Holt, Jason E.; Seamons, Kent E.

doi:10.1145/1030083.1030104

Cited by 120 publications

(82 citation statements)

References 12 publications

(27 reference statements)

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“…For example, Holt [16] also considered security of IBE in the multi-TA setting, motivated by earlier work on anonymous credential systems [17,9]. However, the TA anonymity requirements for these applications are yet to be formally investigated.…”

Section: Discussionmentioning

confidence: 99%

Building Key-Private Public-Key Encryption Schemes

Paterson

Srinivasan

2009

Information Security and Privacy

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Abstract. In the setting of identity-based encryption with multiple trusted authorities, TA anonymity formally models the inability of an adversary to distinguish two ciphertexts corresponding to the same message and identity, but generated using different TA master public-keys. This security property has applications in the prevention of traffic analysis in coalition networking environments. In this paper, we examine the implications of TA anonymity for key-privacy for normal public-key encryption (PKE) schemes. Key-privacy for PKE captures the requirement that ciphertexts should not leak any information about the public-keys used to perform encryptions. Thus key-privacy guarantees recipient anonymity for a PKE scheme. Canetti, Halevi and Katz (CHK) gave a generic transform which constructs an IND-CCA secure PKE scheme using an identitybased encryption (IBE) scheme that is selective-id IND-CPA secure and a strongly secure one-time signature scheme. Their transform works in the standard model (i.e. does not require the use of random oracles). Here, we prove that if the underlying IBE scheme in the CHK transform is TA anonymous, then the resulting PKE scheme enjoys key-privacy. Whilst IND-CCA secure, key-private PKE schemes are already known in the standard-model, our result gives the first generic method of constructing a key-private PKE scheme in the standard model. We then go on to investigate the TA anonymity of multi-TA versions of well-known standard model secure IBE schemes. In particular, we prove the TA anonymity and selective-id IND-CPA security of a multi-TA version of Gentry's IBE scheme. Applying the CHK transform, we obtain a new, efficient keyprivate, IND-CCA secure PKE scheme in the standard model.

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Section: Discussionmentioning

confidence: 99%

Building Key-Private Public-Key Encryption Schemes

Paterson

Srinivasan

2009

Information Security and Privacy

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“…A passive adversary may deduce the policy structure, i.e., the operators (AND, OR, m-of-n threshold encryption) used in the policy but she does not learn what credentials are required to fulfill the access policy unless she possesses them. Bradshaw et al [9] extend the original hidden credentials scheme to limit the partial disclosure of the policy structure and speed up the decryption operations. However, in this scheme, it is not easy to support non-monotonic boolean expressions and range queries in the access policy.…”

Section: Related Workmentioning

confidence: 99%

ESPOONERBAC: Enforcing security policies in outsourced environments

Asghar¹,

Ion²,

Russello³

et al. 2013

Computers & Security

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Data outsourcing is a growing business model offering services to individuals and enterprises for processing and storing a huge amount of data. It is not only economical but also promises higher availability, scalability, and more effective quality of service than in-house solutions. Despite all its benefits, data outsourcing raises serious security concerns for preserving data confidentiality. There are solutions for preserving confidentiality of data while supporting search on the data stored in outsourced environments. However, such solutions do not support access policies to regulate access to a particular subset of the stored data.For complex user management, large enterprises employ Role-Based Access Controls (RBAC) models for making access decisions based on the role in which a user is active in. However, RBAC models cannot be deployed in outsourced environments as they rely on trusted infrastructure in order to regulate access to the data. The deployment of RBAC models may reveal private information about sensitive data they aim to protect. In this paper, we aim at filling this gap by proposing ESPOON ERBAC for enforcing RBAC policies in outsourced environments. ESPOON ERBAC enforces RBAC policies in an encrypted manner where a curious service provider may learn a very limited information about RBAC policies. We have implemented ESPOON ERBAC and provided its performance evaluation showing a limited overhead, thus confirming viability of our approach.

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“…Although these techniques protect authenticators' privacy, they leak community membership to eavesdroppers. Mechanisms such as Key-private encryption [11], affiliation-hiding envelopes [29], hidden credentials [15] and oblivious signaturebased envelopes (OSBEs) [33] can privately share information with 9 1 Note as well that as cellular networks approach their theoretical communication limits, peer-to-peer wireless offer an alternative to further extend wireless throughput between local devices. members of a group.…”

Section: Introductionmentioning

confidence: 99%

Privacy of Community Pseudonyms in Wireless Peer-to-Peer Networks

et al. 2012

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Wireless networks offer novel means to enhance social interactions. In particular, peer-to-peer wireless communications enable direct and real-time interaction with nearby devices and communities and could extend current online social networks by providing complementary services including real-time friend and community detection and localized data sharing without infrastructure requirement. After years of research, the deployment of such peer-to-peer wireless networks is finally being considered. A fundamental primitive is the ability to discover geographic proximity of specific communities of people (e.g, friends or neighbors). To do so, mobile devices must exchange some community identifiers or messages. We investigate privacy threats introduced by such communications, in particular, adversarial community detection. We use the general concept of community pseudonyms to abstract anonymous community identification mechanisms and define two distinct notions of community privacy by using a challenge-response methodology. An extensive cost analysis and simulation results throw further light on the feasibility of these mechanisms in the upcoming generation of wireless peer-to-peer networks.

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Concealing complex policies with hidden credentials

Cited by 120 publications

References 12 publications

Building Key-Private Public-Key Encryption Schemes

Building Key-Private Public-Key Encryption Schemes

ESPOONERBAC: Enforcing security policies in outsourced environments

Privacy of Community Pseudonyms in Wireless Peer-to-Peer Networks

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