Monitoring File Integrity Using Blockchain and Smart Contracts

Abstract

The adoption of cloud computing solutions is an established reality in government agencies and in small, medium, and large companies due to procurement easiness and the variety of available services, as well as its low cost compared to the acquisition and management of own infrastructures. Among the most used services is cloud file storage, and the security of this storage has been an essential subject of recent research, particularly customer data integrity. Thus, this article proposes a solution for the monitoring of the integrity of files stored in the cloud, based on the use of smart contracts in Blockchain Networks, symmetric encryption, and computational trust. The proposed solution consists of a protocol that provides confidentiality, decentralization, audit availability, and the secure sharing of file integrity monitoring results, without overloading the services involved, as well as an unabridged reference implementation which was used to validate the proposal. The results obtained during the validation tests have shown that the solution is feasible and faultless in detecting corrupted files. These tests also confirmed that the sharing of integrity monitoring results, coupled with the application of computational trust techniques, significantly increased the efficiency of the proposed solution.

Validation of Architecture Effectiveness for the Continuous Monitoring of File Integrity Stored in the Cloud Using Blockchain and Smart Contracts

“…The formulas adopted in the calculation processes to increase or decrease the TV/CSS, executed by the methods and , respectively, are described in Section 4.6.4 . As for the conversion of TV/CSS to the trust level attributed to CSS (TL/CSS), the SSTMC uses the trust level classification model shown in Table 2 [ 11 ], which is an adaptation of the classification model proposed in Pinheiro et al [ 10 ]. The TL/CSS and the other information in Table 2 are used in the process of generating and submitting challenges ( Section 4.6.1 ).…”

“…The trust value calculation process (P4 in Figure 7 ) uses the trust calculation model proposed by Pinheiro et al [ 10 ] and adapted by [ 11 ] to allow its implementation in smart contracts and to accelerate the penalization of services that present recurrent failures with the progression of their classification through the various levels of distrust. Conversely, the trust model should also ensure that the CSPs, which maintain their history free from the integrity violation records and strictly comply with the deadlines for generating responses to challenges, are gradually reclassified from the lowest to the highest trust level.…”

“…Pinheiro et al [ 10 ] presented a protocol designed for the periodic monitoring of the integrity of large stored files based on computational trust and symmetric cryptography. Aiming to enhance the referred protocol, improve its efficiency, and increase its security mechanisms, Pinheiro et al [ 11 ] proposed a new architecture that upgraded the protocol proposed in the previous research integrating it with a solution based on blockchain and smart contracts technologies. Notably, this architecture was designed to allow its integration with proprietary solutions adopted by the main cloud service providers (CSPs), such as Google Cloud [ 12 ], AWS [ 13 ], and Azure [ 14 ].…”

“…Notably, this architecture was designed to allow its integration with proprietary solutions adopted by the main cloud service providers (CSPs), such as Google Cloud [ 12 ], AWS [ 13 ], and Azure [ 14 ]. As can be seen in the CSP application proposal presented in [ 11 ], among the characteristics that facilitate its integration, we highlight that the architecture requires only well-known software components and privileges processes whose communication between participants is asynchronous.…”

“…Based on the above, this paper presents a detailed step-by-step description of the process that composes the architecture proposed in [ 11 ]; a security analysis; and a validation of the applicability, effectiveness, and efficiency of this architecture when applied to the monitoring of the integrity of large files stored in the cloud for long periods.…”