Simulating secure cloud storage schemes

Cloud storage services have become a popular solution to store large amounts of data generated by users and enterprises, because they provide an affordable and practical solution. In order to gain efficiency and reduce storage costs, cloud storage servers may remove duplicated copies of the same stored data. This process is called cross-user data deduplication. However, this beneficial procedure is not carried out if the users encrypt their files with their personal keys. To make deduplication and encryption compatible, we can deterministically encrypt a file using a key generated from the file itself. This process is called Message-Locked Encryption (MLE). This thesis aims to analyze and evaluate the security of using MLE in combination with different deduplication strategies. The information leakage incurred by MLE and conventional encryption is studied. A testing environment is also developed to test these schemes in order to fullfil the objectives. After the experiments, we have confirmed that a curious cloud storage server may obtain information about the stored files even when they are encrypted. This leakage is more significant for MLE scheme, but it also exists when the users encrypt the files with their personal keys. This confirms and advances the work of Ritzdorf et al. [18].