Doctoral Thesis / Dissertation from the year 2019 in the subject
Computer Science - Internet, New Technologies, language: English,
abstract: Continuous advancement in software field and widespread use of
software products many innovative applications have emerged, cloud
computing is one of them. In cloud computing users need not to install
software they just log in the cloud and pay for their required service.
As many users are frequently using cloud computing a big question arises
here is the security of user's personal data present at cloud.
Therefore, we need to safeguard the data in the midst of untrusted
processes. On keeping these issues in mind, a security model is designed
in this thesis. The whole model is divided into three sections: one is
data encryption, second is secure data storage and the third one is
maintenance of data integrity. In first section before uploading the
file on cloud, file is encrypted by RSA Partial Homomorphic algorithm.
Two keys public and private are generated after encryption. Between
these two keys public key is known to all but private key is known to
only authorize users. In second section, the data owner uploads the
encrypted file moreover with this one access permission list containing
names of authorized user and their respective permission. In this model
two access permissions (Read Only and Read and Write) are defined by the
data owner. In third section the cloud provider calculates hash value of
uploaded file using MD5 hash algorithm. This hash value is transferred
back to the data owner to use it for verification purpose. As Owner
performs verification, hash value of the desired data present at cloud
is again calculated. Now this new hash value matches with old hash value
which is present at owner end. If it matches no modification is
performed, if hash value does not match then some modifications has been
performed on the uploaded data. After uploading the file on cloud this
file is visible to all users. They can
