Cloud computing is taken into consideration as one of the famed computing strategies for pooling and offering numerous computing resources on call basis. Cloud computing is now become most important part of the IT enterprise and has turn out to be a beneficial desire for small finances commercial enterprise and organizations. As multiple clients are sharing the same public cloud services, cloud users begin thinking of the security of their important data stored on cloud servers managed by the third party. The main goal of this paper is to provide hybrid security model which provides security to cloud storage during transit and at-rest from unauthorized user by using numerous cryptographic services such as user authentication and authorization using OTP or authenticator application, user access control policy, data confidentiality using hybrid encryption algorithm, integrity control using SHA with DSA algorithm, backup module and monitoring system.
Now days, most organizations are migrating to cloud, due to the fact the cloud services are
inexpensive and convenient. For organizations, locating sufficient storage area to preserve all of the
information they obtained is an actual challenge. Some organizations purchase massive amount of
storage drives for storing massive information of organization and yet confronted with problems like
24x7 availability of data, searching, etc [
Cloud Storage is a network based model for storing data wherein the virtual records is saved in
logical pools which spans over different servers, and normally owned and controlled by cloud service
provider. Cloud provides on demand resources or services to everyone like application, data storage
and servers that increases or reduces its resources as peruse with flexibility and cost efficiently. Fig 1
shows the cloud architecture consist of layers like Software as a Service (SaaS): that offers user a
numerous software to be utilized on a cloud infrastructure using web browser or API, Platform as a
Service(PaaS): that provides platform to developer for implementing various software’s frameworks
and storage to be consumed by user and Infrastructure as a Service (IaaS): that offers admin to
customized hardware on demand in maximum universal segments of cloud [
Fig 2 illustrate that cloud service provider deploys there cloud services as public cloud whose
services are available to everyone and multiple user data stored at common place, private cloud whose
services are private generally developed and utilized by private business organizations and can be
accessed only by members of organizations and hybrid cloud which combines the features of public
and private cloud [
Cloud computing is a preferred approach this is determined and appropriate anywhere as it gives
access to the various resources on request of the customers which may be used with much less
interaction with the service issuer and with the minimal cost. It is taken into consideration as a
dominant era due to the fact it could control the huge quantity of information. Cloud computing is
steady and reliable, because of which the companies use this infrastructure without constructing their
own. It is an excellent approach for any sized company or enterprise due to its cost-saving technology.
It provides huge platform which offers various computing resources as a service like application,
frameworks and hardware selection [
Although cloud computing has many features and advantages, it also has few limitation too, and
security issue is always at the top with highest priority. Cloud services have many security challenges
such as integrity control, access control, user identification, resource management and so on. Most
cloud service provider stores private and important data of organization or person through some third
party vendor by way of utility in public domain. Therefore, the threat of essential data going into
unauthorized person or hacker is always there due to the fact cloud offerings are to be had and
reachable through all its users. Hence, there may be the maximum opportunity of improper handling
of personal records or the personal records can be altered deliberately via hackers or different users of
same cloud accidentally. This results in compromised and integrity breach of private information. By
thinking about these types of troubles concerning the security of the information, it's always taken
into consideration as a challenge in cloud service. Cryptography is extensively accredited technique
for making sure the data safety and provides various services and mechanism which assures
confidentiality, integrity control, access control and message authentication [
Mahalle & Shahade, 2014 [
Kiruthika et al., 2015 [
Bindu et al., 2018 [
L. Kumar & Badal, 2019 [
Viswanath & Krishna, 2020 [
The table 1 below provides the brief overview of various security models developed for cloud security.
Several security issues revolve around cloud security and data security. The cloud service provider faces many security challenges. Thus, cloud security model must be developed considering these security challenges and cryptographic mechanism or services must be incorporated in security model to mitigate and ensure the security in cloud environment.
Cloud data security cannot be achieved by merely using hybrid cryptographic algorithm which
utilizes hybrid encryption for enhanced cloud data security. The other security issues in cloud security
should also be address like user authentication and authorization, data integrity, user access control,
and monitoring system [
The proposed hybrid system consist of following module User Authentication- The cloud service provider will provide unique username and password to every user. User will provide this information to cloud for authentication to utilize cloud services. User Authorization- This module will provide extra safety and will be used in conjunction with authentication module. Cloud will verify user's identity by sending newly created random number as One Time Password (OTP) to users mobile or email which is valid for small time span. Cloud system will provide its services to be utilized only after successful verification of OTP. Nowadays 2 factor authentication (2FA) application also integrated as authorization service and proved effective for user authorization. Access Control- This module gives limits the access rights of user within cloud environment. Cloud service provider creates user access policies definition and enforce to user by which various resources are permitted or not permitted to user as per subscription. This module assures that user always access resource that has been authorized to him as per access policy and unauthorized access to cloud data by any user denied and logged for further action. Message Authentication– This module utilizes cryptographic algorithms to assure message integrity and non-repudiation that retrieved data from cloud is correct i.e. no alteration or changes has been done in cloud environment and can verify the identity of data uploader. The SHA256 along with DSA algorithm are used to ensure the integrity of cloud data. Confidentiality – This module provide service that assures that data always remain confidentiality during transit and at rest in cloud. This will be achieved by encrypting data using hybrid algorithm for enhanced security which makes data scrambled and impossible to understand by unauthorized person and can be retrieved only by secret key available with authorize user. Monitoring System- This module provides service that alerts any illegal activity carried out in cloud environment to service provide and user also. Intrusion detection system always monitors network and system activity and raise alerts in abnormal behaviour arises from user or hacker who wants to obtain private information from cloud. Backup Module – This module works internally on scheduled time or on user request for performing backup of cloud data on some other location either on-site (same physical location but different drive) or cloud based (stored in cloud i.e. different geographical location) for disaster management service. 4.2.
Fig 4 shows the flowchart of the proposed hybrid cloud security system which demonstrates how this module communicates with each other during user access to cloud. The monitoring system and backup module always remain active and works in background. The monitoring system module always checks each activity performed in cloud and gives alerts for abnormal activity observed in system module, resource utilization, network traffic or violation of access rules. The backup module takes the backup of cloud data during scheduled time as per configuration. The flowchart can be described in 2 phases as login phase and upload/download phase.
Login Phase: The user attempts to access cloud will always first go to login phase where 3 different module works together to perform security check for ensuring user identity and enforcing access control rules. The authentication module utilizes basic username and password to verify register user followed by authorization module which ensures the user’s identity and based on user role the access control module enforces the access policy rules as defined by service provider.
Upload/Download Phase: Cloud always needs that user must be logged in system for user data upload or download request. The data upload request handle by message authentication module which creates digital signature for integrity control and non-repudiation service and then applies encryption algorithm for privacy of data before storing data on cloud. The reverse procedure is followed during download request i.e. data is decrypted first then by message authentication module checks that the digital signature matches (stored in upload request and newly created from downloaded data) for assuring data integrity can also verify the originator of data if required.
Cloud services around the world increased due to the recent covid-19 pandemic. Security issues in cloud environment still have a huge horizon for companies and hackers that both can workaround and earn rewards. Cloud service providers offer their services on various parameters like hardware selection, resource requirement, pricing, flexibility, support system, etc with some security features. Our proposed hybrid cloud system covers majority of security challenges exist in cloud environment like CIA, AAAC, physical location, data backup and multi-tenancy. The proposed system utilizes and mixes numerous cryptographic mechanism and services to provide enhanced security model for cloud data security such as user authentication and authorization using OTP or authenticator application, user access control policy, data confidentiality using hybrid encryption algorithm, message authentication using SHA with DSA algorithm, backup module and monitoring system.