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Compact Proofs of Retrievability
, 2008
"... In a proof-of-retrievability system, a data storage center must prove to a verifier that he is actually storing all of a client’s data. The central challenge is to build systems that are both efficient and provably secure — that is, it should be possible to extract the client’s data from any prover ..."
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Cited by 197 (0 self)
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In a proof-of-retrievability system, a data storage center must prove to a verifier that he is actually storing all of a client’s data. The central challenge is to build systems that are both efficient and provably secure — that is, it should be possible to extract the client’s data from any prover that passes a verification check. All previous provably secure solutions require that a prover send O(l) authenticator values (i.e., MACs or signatures) to verify a file, for a total of O(l 2) bits of communication, where l is the security parameter. The extra cost over the ideal O(l) communication can be prohibitive in systems where a verifier needs to check many files. We create the first compact and provably secure proof of retrievability systems. Our solutions allow for compact proofs with just one authenticator value — in practice this can lead to proofs with as little as 40 bytes of communication. We present two solutions with similar structure. The first one is privately verifiable and builds elegantly on pseudorandom functions (PRFs); the second allows for publicly verifiable proofs and is built from the signature scheme of Boneh, Lynn, and Shacham in bilinear groups. Both solutions rely on homomorphic properties to aggregate a proof into one small authenticator value. 1
Cryptographic Cloud Storage
"... We consider the problem of building a secure cloud storage service on top of a public cloud infrastructure where the service provider is not completely trusted by the customer. We describe, at a high level, several architectures that combine recent and non-standard cryptographic primitives in order ..."
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Cited by 131 (1 self)
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We consider the problem of building a secure cloud storage service on top of a public cloud infrastructure where the service provider is not completely trusted by the customer. We describe, at a high level, several architectures that combine recent and non-standard cryptographic primitives in order to achieve our goal. We survey the benefits such an architecture would provide to both customers and service providers and give an overview of recent advances in cryptography motivated specifically by cloud storage. 1
Privacy-Preserving Public Auditing for Secure Cloud Storage
, 2009
"... Using Cloud Storage, users can remotely store their data and enjoy the on-demand high quality applications and services from a shared pool of configurable computing resources, without the burden of local data storage and maintenance. However, the fact that users no longer have physical possession o ..."
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Cited by 75 (3 self)
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Using Cloud Storage, users can remotely store their data and enjoy the on-demand high quality applications and services from a shared pool of configurable computing resources, without the burden of local data storage and maintenance. However, the fact that users no longer have physical possession of the outsourced data makes the data integrity protection in Cloud Computing a formidable task, especially for users with constrained computing resources. Moreover, users should be able to just use the cloud storage as if it is local, without worrying about the need to verify its integrity. Thus, enabling public auditability for cloud storage is of critical importance so that users can resort to a third party auditor (TPA) to check the integrity of outsourced data and be worry-free. To securely introduce an effective TPA, the auditing process should bring in no new vulnerabilities towards user data privacy, and introduce no additional online burden to user. In this paper, we propose a secure cloud storage system supporting privacy-preserving public auditing. We further extend our result to enable the TPA to perform audits for multiple users simultaneously and efficiently. Extensive security and performance analysis show the proposed schemes are provably secure and highly efficient.
A Secure Erasure Code-Based Cloud Storage System with Secure Data Forwarding
- IEEE Trans. Parallel and Distributed Systems
, 2012
"... Abstract—A cloud storage system, consisting of a collection of storage servers, provides long-term storage services over the Internet. Storing data in a third party’s cloud system causes serious concern over data confidentiality. General encryption schemes protect data confidentiality, but also limi ..."
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Cited by 26 (0 self)
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Abstract—A cloud storage system, consisting of a collection of storage servers, provides long-term storage services over the Internet. Storing data in a third party’s cloud system causes serious concern over data confidentiality. General encryption schemes protect data confidentiality, but also limit the functionality of the storage system because a few operations are supported over encrypted data. Constructing a secure storage system that supports multiple functions is challenging when the storage system is distributed and has no central authority. We propose a threshold proxy re-encryption scheme and integrate it with a decentralized erasure code such that a secure distributed storage system is formulated. The distributed storage system not only supports secure and robust data storage and retrieval, but also lets a user forward his data in the storage servers to another user without retrieving the data back. The main technical contribution is that the proxy re-encryption scheme supports encoding operations over encrypted messages as well as forwarding operations over encoded and encrypted messages. Our method fully integrates encrypting, encoding, and forwarding. We analyze and suggest suitable parameters for the number of copies of a message dispatched to storage servers and the number of storage servers queried by a key server. These parameters allow more flexible adjustment between the number of storage servers and robustness. Index Terms—Decentralized erasure code, proxy re-encryption, threshold cryptography, secure storage system. Ç 1
Data storage auditing service in cloud computing: challenges, methods and opportunities
, 2012
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A Privacy-Preserving Remote Data Integrity Checking Protocol with Data Dynamics and Public Verifiability
"... Remote data integrity checking is a crucial technology in cloud computing. Recently many works focus on providing data dynamics and/or public verifiability to this type of protocols. Existing protocols can support both features with the help of a third party auditor. In a previous work, Sebé et al. ..."
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Cited by 21 (0 self)
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Remote data integrity checking is a crucial technology in cloud computing. Recently many works focus on providing data dynamics and/or public verifiability to this type of protocols. Existing protocols can support both features with the help of a third party auditor. In a previous work, Sebé et al. [1] propose a remote data integrity checking protocol that supports data dynamics. In this paper, we adapt Sebé et al.’s protocol to support public verifiability. The proposed protocol supports public verifiability without help of a third party auditor. In addition, the proposed protocol does not leak any private information to third party verifiers. Through a formal analysis, we show the correctness and security of the protocol. After that, through theoretical analysis and experimental results, we demonstrate that the proposed protocol has a good performance.
Dynamic Proofs of Retrievability via Oblivious RAM
, 2012
"... Proofs of retrievability allow a client to store her data on a remote server (e.g., “in the cloud”) and periodically execute an efficient audit protocol to check that all of the data is being maintained correctly and can be recovered from the server. For efficiency, the computation and communication ..."
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Cited by 15 (2 self)
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Proofs of retrievability allow a client to store her data on a remote server (e.g., “in the cloud”) and periodically execute an efficient audit protocol to check that all of the data is being maintained correctly and can be recovered from the server. For efficiency, the computation and communication of the server and client during an audit protocol should be significantly smaller than reading/transmitting the data in its entirety. Although the server is only asked to access a few locations of its storage during an audit, it must maintain full knowledge of all client data to be able to pass. Starting with the work of Juels and Kaliski (CCS ’07), all prior solutions to this problem crucially assume that the client data is static and do not allow it to be efficiently updated. Indeed, they all store a redundant encoding of the data on the server, so that the server must delete a large fraction of its storage to ‘lose ’ any actual content. Unfortunately, this means that even a single bit modification to the original data will need to modify a large fraction of the server storage, which makes updates highly inefficient. Overcoming this limitation was left as the main open problem by all prior works. In this work, we give the first solution providing proofs of retrievability for dynamic storage, where the client can perform arbitrary reads/writes on any location within her data by running an efficient protocol
Fully homomorphic message authenticators
- IACR Cryptology ePrint Archive
"... We define and construct a new primitive called a fully homomorphic message authenticator. With such scheme, anybody can perform arbitrary computations over authenticated data and produce a short tag that authenticates the result of the computation (without knowing the secret key). This tag can be ve ..."
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Cited by 15 (4 self)
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We define and construct a new primitive called a fully homomorphic message authenticator. With such scheme, anybody can perform arbitrary computations over authenticated data and produce a short tag that authenticates the result of the computation (without knowing the secret key). This tag can be verified using the secret key to ensure that the claimed result is indeed the correct output of the specified computation over previously authenticated data (without knowing the underlying data). For example, Alice can upload authenticated data to “the cloud”, which then performs some specified computations over this data and sends the output to Bob, along with a short tag that convinces Bob of correctness. Alice and Bob only share a secret key, and Bob never needs to know Alice’s underlying data. Our construction relies on fully homomorphic encryption to build fully homomorphic message authenticators. 1
Provable possession and replication of data over cloud servers
"... Abstract. Cloud Computing (CC) is an emerging computing paradigm that can potentially offer a number of important advantages. One of the fundamental advantages of CC is pay-as-you-go pricing model, where customers pay only according to their usage of the services. Currently, data generation is outpa ..."
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Cited by 14 (4 self)
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Abstract. Cloud Computing (CC) is an emerging computing paradigm that can potentially offer a number of important advantages. One of the fundamental advantages of CC is pay-as-you-go pricing model, where customers pay only according to their usage of the services. Currently, data generation is outpacing users ’ storage availability, thus there is an increasing need to outsource such huge amount of data. Outsourcing data to a remote Cloud Service Provider (CSP) is a growing trend for numerous customers and organizations alleviating the burden of local data storage and maintenance. Moreover, customers rely on the data replication provided by the CSP to guarantee the availability and durability of their data. Therefore, Cloud Service Providers (CSPs) provide storage infrastructure and web services interface that can be used to store and retrieve an unlimited amount of data with fees metered in GB/month. The mechanisms used for data replication vary according to the nature of the data; more copies are needed for critical data that cannot easily be reproduced. This critical data should be replicated on multiple servers across multiple data centers. On the other hand, non-critical, reproducible data are stored at reduced levels of redundancy. The pricing model is related to the replication strategy. Therefore, it is of crucial importance to customers to have a strong evidence that they actually get the service they pay for. Moreover, they need to verify that all their data copies are not being tampered with or partially deleted over time. Consequently, the problem of Provable Data Possession (PDP) has been considered in many research papers. Unfortunately, previous PDP schemes focus on a single copy of the data and provide no guarantee that the CSP stores multiple copies of customers ’ data. In this paper we address this challenging issue and propose Efficient Multi-Copy Provable Data Possession (EMC-PDP) protocols. We prove the security of our protocols against colluding servers. Through extensive performance analysis and experimental results, we demonstrate the efficiency of our protocols.
An Efficient and Secure Dynamic Auditing Protocol for Data Storage in Cloud Computing
"... Abstract—In cloud computing, data owners host their data on cloud servers and users (data consumers) can access the data from cloud servers. Due to the data outsourcing, however, this new paradigm of data hosting service also introduces new security challenges, which requires an independent auditing ..."
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Cited by 13 (0 self)
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Abstract—In cloud computing, data owners host their data on cloud servers and users (data consumers) can access the data from cloud servers. Due to the data outsourcing, however, this new paradigm of data hosting service also introduces new security challenges, which requires an independent auditing service to check the data integrity in the cloud. Some existing remote integrity checking methods can only serve for static archive data and thus cannot be applied to the auditing service since the data in the cloud can be dynamically updated. Thus, an efficient and secure dynamic auditing protocol is desired to convince data owners that the data are correctly stored in the cloud. In this paper, we first design an auditing framework for cloud storage systems and propose an efficient and privacy-preserving auditing protocol. Then, we extend our auditing protocol to support the data dynamic operations, which is efficient and provably secure in the random oracle model. We further extend our auditing protocol to support batch auditing for both multiple owners and multiple clouds, without using any trusted organizer. The analysis and simulation results show that our proposed auditing protocols are secure and efficient, especially it reduce the computation cost of the auditor.
