AnonyControl: Control Cloud Data Anonymously with Multi-Authority Attribute-Based Encryption (1206.2657v6)

Abstract: Cloud computing is a revolutionary computing paradigm which enables flexible, on-demand and low-cost usage of computing resources. However, those advantages, ironically, are the causes of security and privacy problems, which emerge because the data owned by different users are stored in some cloud servers instead of under their own control. To deal with security problems, various schemes based on the Attribute- Based Encryption (ABE) have been proposed recently. However, the privacy problem of cloud computing is yet to be solved. This paper presents an anonymous privilege control scheme AnonyControl to address the user and data privacy problem in a cloud. By using multiple authorities in cloud computing system, our proposed scheme achieves anonymous cloud data access, finegrained privilege control, and more importantly, tolerance to up to (N -2) authority compromise. Our security and performance analysis show that AnonyControl is both secure and efficient for cloud computing environment.

• The paper introduces a novel multi-authority ABE framework that fragments private key generation to ensure no single authority can deduce a user’s full identity.
• The paper demonstrates that the scheme withstands the compromise of up to N-2 authorities, thereby ensuring robust protection against potential data breaches.
• The paper validates its approach with a real toolkit implementation, proving efficient encryption and fine-grained access control in real-world cloud environments.

Overview of Privacy Preserving Cloud Data Access With Multi-Authorities

The paper "Privacy Preserving Cloud Data Access With Multi-Authorities" by Jung et al. tackles the integral challenges of secure and private data management in cloud environments. As cloud computing becomes increasingly prevalent for its dynamic resource allocation, it simultaneously presents significant security and privacy obstacles due to third-party data storage. This paper aims to address these challenges through a novel anonymous privilege control scheme named AnonyControl that employs multiple authorities to enhance user privacy and data security.

Motivation and Background

Cloud computing has revolutionized resource usage, offering scalable and cost-effective data management solutions. Yet, the delegation of data storage to external servers introduces potential violations of data confidentiality and user privacy. Existing access control mechanisms often rely on Attribute-Based Encryption (ABE), which, while useful, leaves user identities vulnerable due to centralized authority structures. AnonyControl's multi-authority framework endeavors to obscure user identities while imposing fine-grained access control, thus mitigating such privacy issues.

Current methodologies such as Identity-Based Encryption (IBE) and its variant, Attribute-Based Encryption (ABE), lay the foundation for secure access control. However, they fall short in privacy preservation as they often require central control and expose user attributes to key generators. The extension of ABE by incorporating multiple authorities, as proposed by Chase and others, showcases a shift towards decentralized systems, although they are constrained by expressibility in terms of flexible policies.

Key Contributions

The primary contributions of this paper are articulated through the following four points:

1. User Privacy Preservation: AnonyControl enhances privacy by allowing multiple authorities to issue components of a user's private key independently. This fragmentation ensures that no single authority can wholly deduce any user's identity from their attribute set.
2. Resilience to Authority Compromise: The suggested scheme is robust against the compromise of up to $N-2$ authorities, where $N$ represents the total number of authorities in the system. This resilience is crucial in mitigating data breaches even if multiple authorities are infiltrated.
3. Security and Efficiency: Comprehensive security proof and performance analysis demonstrate that AnonyControl is both secure and efficient. The encryption and decryption algorithms provide reliable access control without excessive computational overhead.
4. Real Toolkit Implementation: The paper not only theorizes but also implements the proposed system, marking it as one of the pioneering efforts in multi-authority ABE schemes. This practical aspect highlights its potential applicability in real-world cloud storage systems.

Methodology

AnonyControl operates by distributing attribute control across multiple sovereign authorities, each managing a unique attribute subset. The encryption process employs Ciphertext-Policy Attribute-Based Encryption (CP-ABE) wherein ciphertexts include privilege trees defining access policies. These trees determine permissible operations over encrypted data, effectively instilling fine-grained access control measures. The use of bilinear pairing and Secret Sharing Schemes ensures that only compliant users can decrypt data.

Key generation and management are decentralized. Authorities issue attribute-specific components of the user's private key without gaining comprehensive knowledge of the entire user attribute set. Such decentralization deters collusion, as even compromised authorities lack sufficient information to reconstruct the user's identity or access complete data.

Implications and Future Directions

This research advances the field by balancing the dual necessities of data confidentiality and user privacy. The multi-authority framework proposed could catalyze further research into decentralized attribute-based systems, addressing both technical and sociopolitical concerns regarding data sovereignty and surveillance.

Looking forward, AnonyControl could integrate with existing systems to provide enhanced security layers for sensitive cloud-based applications like healthcare and finance. Further optimization of scalability and integration with Global Identity Management systems presents fertile ground for subsequent research. Additionally, exploring adaptive access policies and their impact on data management offers intriguing avenues for extending this work.

In conclusion, AnonyControl presents a significant stride in secure cloud computing, offering a nuanced approach to data access. Its practical implementation suggests that privacy-preserving mechanisms are not only theoretically viable but also operationally feasible, promising a more secure cloud ecosystem.