# RACHEM: Reinforced Reliable Computing in Cloud by Ensuring Restricted Access Control
## 2 Literature Survey
### Identified Research Gaps and Objectives  
In recent times, researchers have suggested various cryptographic and access control solutions to protect the data of the owner that is uploaded onto the cloud [86; 87; 88; 89; 90]. The work illustrated in [86] introduced a RBAC framework that leverages partial homomorphic encryption (PHE) to ensure fine-grained data access control in cloud environments. The model allows computations on encrypted data without decryption, maintaining data confidentiality while enabling efficient access control. The work of [87] demonstrates a novel RBAC scheme combining identity-based encryption (IBE) and broadcast encryption to securely manage cloud data access. This dual encryption strategy strengthens user authentication and streamlines data sharing among authorized groups without compromising security. Furthermore, a trust-oriented role-based access control for maintaining data integrity in the cloud was provisioned in [88]. This paper enhanced security in traditional RBAC by incorporating trust evaluation mechanisms, aiming to prevent insider threats and unauthorized access. It used trust metrics to dynamically adjust access permissions, ensuring that only trusted entities can access sensitive data. A recommendation-driven trust model was proposed in [89] that predicted trustworthiness of a service user based on previous interactions and ratings. This model enhanced security in cloud systems by intelligently assessing user behavior and guiding access decisions using predicted trust scores. To demonstrate identity governance, an identity-based broadcast encryption scheme was suggested in [90]. The paper focused on reducing computational overhead while preserving security standards, particularly in multi-user data sharing scenarios. Although various schemes have been proposed across domains such as privileged access, IAM, RBAC, and ABAC, some critical research gaps (REG) still remain, as outlined below: \begin{table}
\begin{tabular}{c c c} \hline \hline
**Research Work** & **Contributions** & **Gaps** \\ \hline
[74] & Introduced hierarchical cryptographic models for access control. & Initial model, lacks revocation and audit features. \\ \hline
[75; 76; 77; 78] & Suggested economic schemes for outsourcing access control. & Limited to policy definition without cryptographic depth. \\ \hline
[79; 80; 81] & Proposed HIBE to control access using hierarchical identities. & Requires full hierarchical structure; rigid in dynamic settings. \\ \hline
[82] & Suggested private key generation scheme in HIBE; suffers single-point failure. & Fails under root key compromise; lacks resilience. \\ \hline
[83] & Shifted to Hierarchical Key Management (HKM). & Does not integrate cryptographic access validation. \\ \hline
[84] & Introduced Industrial Control System (ICS) vulnerability and cyber-physical attack assessments. & Lacks mitigation schemes if system is compromised. \\ \hline
[85] & Proposed probabilistic task reliability model under unauthorized access. & Ignores task dependency and synchronization challenges. \\ \hline \hline \end{tabular}
\end{table} 
Table 1: _Cont._REG-1: The traditional cryptosystems do not incorporate governance schemes to handle vulnerable CSP, so there is a need to hide the contents of the owner's data from the CSP itself. REG-2: The conventional role-based access control models do not have efficient identity-based access management policies to validate user role credentials and to handle unauthorized activities by the revoked users. To handle the identified research gaps, this work formulates the following research objectives (REO). This sub-section depicts the coherency between the identified gaps and the formulated research objectives to ensure security in cloud computing systems. REO-1 (Addressing REG-1): To design a secure access control framework that integrates cryptographic mechanisms for enabling confidential resource computation at the CSP, thereby ensuring that data content remains hidden from the CSP itself.