e chapters in this part have described the experimental secure cloud systems that
we have developed including secure cloud query processing and secure information
In Chapter 22, we presented a system that allows cooperating organizations to
securely share large amounts of data. We have ensured that the organizations have a
large common storage area by using Hadoop. Further, we have used Hive to present
users of our system with a structured view of the data and to also enable them to
query the data with a SQL-like language.
In Chapter 23, we have described access control mechanisms for semantic web
data stored in the cloud. Our implemented mechanism incorporates a token-based
access control system where users of the system are granted tokens based on busi-
ness needs and authorization levels.
In Chapter 24, we described techniques to protect our data by encrypting it
before storing on cloud computing servers like Amazon S3. Our approach is novel
as we propose to use two key servers to generate and store the keys. Also, we pro-
vide more security than some of the other known approaches as we do not store the
actual key used to encrypt the data. is assures the protection of our data even if
one or both key servers are compromised.