Enabling Data Integrity Protection in Regenerating-Coding-Based Cloud Storage: Theory and Implementation

To protect outsourced data in cloud storage against corruptions, adding fault tolerance to cloud storage, along with efficient data integrity checking and recovery procedures, becomes critical. Regenerating codes provide fault tolerance by striping data across multiple servers, while using less repair traffic than traditional erasure codes during failure recovery. Therefore, we study the problem of remotely checking the integrity of regenerating-coded data against corruptions under a real-life cloud storage setting. We design and implement a practical data integrity protection (DIP) scheme for a specific regenerating code, while preserving its intrinsic properties of fault tolerance and repair-traffic saving. Our DIP scheme is designed under a mobile Byzantine adversarial model, and enables a client to feasibly verify the integrity of random subsets of outsourced data against general or malicious corruptions. It works under the simple assumption of thin-cloud storage and allows different parameters to be fine-tuned for a performance-security trade-off. We implement and evaluate the overhead of our DIP scheme in a real cloud storage testbed under different parameter choices. We further analyze the security strengths of our DIP scheme via mathematical models. We demonstrate that remote integrity checking can be feasibly integrated into regenerating codes in practical deployment.

1 Introduction

Cloud storage offers an on-demand data outsourcing service model, and is gaining popularity due to its elasticity and low maintenance cost. However, security concerns arise when data storage is outsourced to third-party cloud storage providers. It is desirable to enable cloud clients to verify the integrity of their outsourced data, in case their data have been accidentally corrupted or maliciously compromised by insider/outsider attacks.