Securely Outsourcing Exponentiations with Single Untrusted Program for Cloud Storage

Wang, Yujue; Wu, Qianhong; Wong, Duncan S.; Qin, Bo; Chow, Sherman S. M.; Liu, Zhen; Tan, Xiao

doi:10.1007/978-3-319-11203-9_19

Cited by 77 publications

(103 citation statements)

References 26 publications

(47 reference statements)

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“…5. Our algorithm for the case of simultaneous modular exponentiation is more efficient than the existing algorithms [2] and [5] (there is only a generalized result in [22], for which the checkability fails as explained above). The algorithm proposed in [2] only considers two simultaneous modular exponentiations.…”

Section: Our Contributionsmentioning

confidence: 99%

“…Many algorithms have been proposed for outsourcing computation [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. They aim either to have a better outsourcing security model or to have more efficient constructions.…”

Section: Related Workmentioning

confidence: 99%

“…3. In [5], the authors propose the first generic algorithm for a single untrusted server considering private-base & private-exponent. Furthermore, it has fixed 1/2 checkability probability.…”

Section: Our Contributionsmentioning

confidence: 99%

“…However, their scheme is quite inefficient since it requires approximately 2000 modular multiplications. In contrast to this scheme, we would like to highlight that our private-base & privateexponent algorithm Alg pr pr is the most efficient and verifiable solution with respect to the existing ones (e.g., we have ≈ 10, 17 times less MMs than the only existing algorithm [5]). 4.…”

Section: Our Contributionsmentioning

confidence: 99%

“…In this work, we follow the security model proposed by Hohenberger and Lysyanskaya [3] like the recent results in [2,5]. Assume that a client C would like to securely outsource an expensive cryptographic computation Alg to a cloud server S. Our aim is to split the computation into two main procedures (1) C knows the input value to Alg, (2) C invokes S which is an untrusted server that can carry out expensive computation operations.…”

Section: Security and Privacy Modelmentioning

confidence: 99%

See 4 more Smart Citations

Efficient and verifiable algorithms for secure outsourcing of cryptographic computations

Kiraz

Uzunkol

2015

Int. J. Inf. Secur.

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Reducing computational cost of cryptographic computations for resource-constrained devices is an active research area. One of the practical solutions is to securely outsource the computations to an external and more powerful cloud server. Modular exponentiations are the most expensive computation from the cryptographic point of view. Therefore, outsourcing modular exponentiations to a single, external and potentially untrusted cloud server while ensuring the security and privacy provide an efficient solution. In this paper, we propose new efficient outsourcing algorithms for modular exponentiations using only one untrusted cloud server. These algorithms cover public-base & private-exponent, private-base & public-exponent, private-base & privateexponent, and more generally private-base & private-exponents simultaneous modular exponentiations. Our algorithms are the most efficient solutions utilizing only one single untrusted server with best checkability probabilities. Furthermore, unlike existing schemes, which have fixed checkability probability, our algorithms provide adjustable predetermined checkability parameters. Finally, we apply our algorithms to outsource Oblivious Transfer Protocols and Blind Signatures which are expensive primitives in modern cryptography.

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Section: Our Contributionsmentioning

confidence: 99%

Section: Related Workmentioning

confidence: 99%

Section: Our Contributionsmentioning

confidence: 99%

Section: Our Contributionsmentioning

confidence: 99%

Section: Security and Privacy Modelmentioning

confidence: 99%

See 3 more Smart Citations

Efficient and verifiable algorithms for secure outsourcing of cryptographic computations

Kiraz

Uzunkol

2015

Int. J. Inf. Secur.

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Parallel checking of content integrity in multi‐cloud storage of heterogeneous sensor systems

Mao

Chen

Yan

et al. 2016

Int J Communication

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Heterogeneous sensor systems collect a large amount of sensor data. Because of limited processing capability of sensor nodes, such data are typically stored and processed in a centralized environment in the cloud. However, when data are managed and processed by multiple cloud servers, users do not physically possess these data. The risk of unauthorized access to the cloud data increases dramatically. Therefore, enforcing the integrity of the outsourced data remotely becomes a challenge in the heterogeneous sensor system. Remote data possession auditing is a solution to guarantee the availability and integrity of data outsourced to the cloud. Most existing solutions only target at a single cloud service provider (CSP) environment without considering the multi-cloud scenario. How to audit the data possession among the distributed CSP servers effectively becomes a major concern. In this paper, we propose a parallel cloud data possession checking scheme for the multi-cloud environment. Our approach utilizes the homomorphic verification tag created by the Paillier cryptosystem to support unlimited query challenges and introduces the error-correction encoding method to ensure error localization and data correction. We prototype our solution and analyze the scheme comprehensively. Our evaluation results demonstrate the efficiency and security of our method. It also supports simultaneous verification of multiple CSPs. Figure 1. Overall architecture of heterogeneous sensor system.As another example, heterogeneous sensors are also used in earthquake or volcano monitoring, where different types of sensors, including temperature and acceleration, are used to obtain environmental data that are processed in cloud servers [5]. When such systems are integrated with cloud-storage infrastructure, users lose the physical possession of the out-sourced data. There is a dramatic increase in the potential risk in unauthorized access to the data, such as the incident in the S3 service of Amazon [6]. We will present the generalized architecture in Section 3.Intuitively, to ensure that data are stored correctly, we can verify data using general cryptographicbased approaches, for example, hash functions and digital signature schemes. Deswarte et al. [7,8] first make use of the RSA signature scheme combined with hash functions to verify the correctness of outsourced files. However, such a verification scheme needs to access or retrieve the whole outsourced data, which will cause high performance overhead (e.g., computation complexity and communication cost).The work of [9, 10], and [11] proposed the provable data possession model. To reduce the computation and communication cost, these schemes utilize the sampling technique combined with homomorphic verification instead of the whole-file retrieval verification. The approach proposed by Ateniese et al. [9] supports public data possession audit with unbounded times of challenge. Most previous schemes only verify the data correctness without error identification, localization, and correction. ...

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Secure delegation of group exponentiations: Efficient and fully verifiable schemes with two servers†

Moritz

Uzunkol

2019

Security and Privacy

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Recent interactions between cloud service providers and mobile resource‐constrained devices have increased the interest on the delegation of expensive computations to powerful external server providers. At the same time, security and verifiability of the delegated computation are challenging though highly demanded requirements for various application scenarios. Many security solutions using advanced cryptographic technologies require a large number of highly expensive group exponentiations (GEs). In this paper, we address the problems regarding secure and verifiable delegation of GEs. We first analyze two delegation schemes for GEs both introduced recently in Cluster Computing by Fu et al with the claim that they both provide full verifiability. Particularly, we show that the first scheme is only verifiable with a probability at most 2/3, and the second scheme is totally unverifiable. Then, we propose a secure, efficient and fully verifiable delegation scheme InvDel for a GE using two servers, where one of which is malicious. With InvDel the delegator does not require computations of any group inversions (GIs) while providing full verifiability. Then, we extend InvDel to SimInvDel which is the first, efficient and secure delegation scheme for n‐simultaneous GEs achieving full verifiability for n > 1. Secondly, we give implementation results of InvDel and SimInvDel using an Android application together with a comprehensive efficiency analysis of computation and communication with the previous schemes. For instance, when the required CPU costs for a single GE are compared with a 4092‐bit modulus, InvDel is more than 220‐times (resp. more than two times) more efficient than the local computation (resp. using a previous fully verifiable scheme proposed in the literature). Finally, we also utilize InvDel and SimInvDel to speed‐up the verification of Schnorr's signature and Cramer‐Shoup encryption schemes.

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Securely Outsourcing Exponentiations with Single Untrusted Program for Cloud Storage

Cited by 77 publications

References 26 publications

Efficient and verifiable algorithms for secure outsourcing of cryptographic computations

Efficient and verifiable algorithms for secure outsourcing of cryptographic computations

Parallel checking of content integrity in multi‐cloud storage of heterogeneous sensor systems

Secure delegation of group exponentiations: Efficient and fully verifiable schemes with two servers†

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