Enhancing security of cloud computing based on cryptography / Rasha Abdelkader Refaie ; Supervised Hesham A. Hefny , Abdelaziz A. Abdelaziz

Thesis (M.Sc.) - Cairo University - Institute of Statistical Studies and Research - Department of Information Systems and Technology

Cloud computing means storing and accessing data and programs over the internet instead of your computer{u2019}s hard drive. The cloud computing offers service over internet with dynamically scalable resources. Computing services provide benefits to the users in terms of ease of use and pay as you go and only for what you use. Cloud has boomed high in business and other industries for its advantages like multi-tenancy, resource pooling, storage capacity etc. Cloud computing allow companies to out source data and computations on demand. When data out source sensitive information become vulnerable to theft. Various techniques have been proposed to preserve a certain degree of privacy on database and allowing to execute queries efficiently on cloud computing. These techniques cannot support all queries over encrypted data. In this thesis, two secure techniques are proposed for executing queries over encrypted data.The proposed techniques build on CryptDB{u2019}s design. These techniques eliminate the limitation of cryptDB to perform server-side computations on values encrypted for different principals. The first technique tries to overcome this limitation by suggesting two tables for a single main table. The first table contains the encrypted data and the second one containing columns which has values encrypted by different keys and ID column in plain form. Whenever a search condition is on a column containing data encrypted with different keys, hence, the search will be performed on the Search_Table. In this technique the proxy does not need to decrypt all the values of the entire encrypted column; rather it decrypts only those values which satisfy the user query. The second proposed technique tries to overcome this limitation by encrypted the query with different keys and run every query on the corresponding data which encrypted by the same key. These queries will return these records which exactly the user wants from Encrypted_Table. The proxy decrypts only those values which satisfy the user query

Issued also as CD