## 2 Literature Work
### Attribute-Based Encryption (ABE)  
The authors of [18] developed the key-policy attribute-based encryption (KP-ABE) method. The KP-ABE method illustrated that the ciphertext is presented in the set of attributes and secret keys. The authors of [19] presented an ABE method concerning the location of access control. The authors formulated the problem of attacks on secret keys to impede the applications of KP-ABE. The technique was further investigated in [20] to improve ABE's efficiency by exploiting overlooked facts, i.e., the hierarchical links among the attributes in access control. The authors of [17] investigated the attribute-based broadcast encryption. The authors tried to solve an efficient, constant, private-key ciphertext-policy ABBE scheme for fast decryption. In [21], the authors considered a key-exchange protocol based on CP-ABE to establish authentic and confidential communications. Furthermore, the authors of [22] proposed a fully policy-hidden CP-ABE scheme constructed on the linear secret-sharing-scheme access structure and prime-order groups for public cloud data sharing. In [23], an extended file hierarchy CP-ABE scheme is proposed to encrypt multiple files on the same access level. The authors provide secure and flexible access control for users in cloud storage. The authors of [24] proposed an ABE scheme with adaptive security for cloud-assisted IoTs. The authors achieved access control, revocability and adaptive security under formal-decision linear assumptions. Finally, the authors of [25] proposed CP-ABE with arithmetic span programs to reduce the unnecessary cost of defining the  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Ref** & **Methodology** & **ABE** & **MA-ABE** & **AR-ABE** & **O-ABE** \\ \hline
[17] & CP-ABE & ✓ & \(\times\) & \(\times\) & ✓ \\
[18] & KP-ABE & ✓ & \(\times\) & \(\times\) & \(\times\) \\
[19] & ABE & ✓ & \(\times\) & \(\times\) & \(\times\) \\
[20] & ABE & ✓ & \(\times\) & \(\times\) & \(\times\) \\
[21] & ABE & ✓ & \(\times\) & \(\times\) & ✓ \\
[22] & Fully policy-hidden CP-ABE & ✓ & \(\times\) & \(\times\) & ✓ \\
[23] & Hierarchy CP-ABE & ✓ & \(\times\) & \(\times\) & ✓ \\
[24] & ABE & ✓ & \(\times\) & \(\times\) & ✓ \\
[25] & CP-ABE & ✓ & \(\times\) & \(\times\) & ✓ \\
[26] & CP-MA-ABE & ✓ & ✓ & \(\times\) & \(\times\) \\
[13] & MA-ABE & ✓ & ✓ & \(\times\) & \(\times\) \\
[27] & MA-ABE & ✓ & ✓ & \(\times\) & \(\times\) \\
[28] & MA-ABE & ✓ & ✓ & \(\times\) & \(\times\) \\
[29] & Chase’s scheme & ✓ & ✓ & \(\times\) & \(\times\) \\
[30] & MA-ABE & ✓ & ✓ & \(\times\) & \(\times\) \\
[31] & MA-ABE & ✓ & ✓ & \(\times\) & \(\times\) \\
[32] & ABE & ✓ & \(\times\) & ✓ & \(\times\) \\
[33] & Proxy Re-encryption & ✓ & \(\times\) & ✓ & \(\times\) \\
[34] & Access control policies & ✓ & \(\times\) & ✓ & \(\times\) \\
[35] & MR-ABE & ✓ & \(\times\) & ✓ & \(\times\) \\
[14] & CA-CP-ABE & ✓ & \(\times\) & ✓ & \(\times\) \\
[36] & AR-ABE & ✓ & \(\times\) & ✓ & \(\times\) \\
[37] & AR-ABE & ✓ & \(\times\) & ✓ & \(\times\) \\
[38] & Privacy protection & ✓ & \(\times\) & \(\times\) & ✓ \\
[39] & CPA and RCCA & ✓ & \(\times\) & \(\times\) & ✓ \\
[40] & ABE and CCA & ✓ & \(\times\) & \(\times\) & ✓ \\
[41] & CP-ABE & ✓ & \(\times\) & \(\times\) & ✓ \\
[42] & Fine-grained access control & ✓ & \(\times\) & \(\times\) & ✓ \\
[43] & FS-PKSE & ✓ & \(\times\) & \(\times\) & ✓ \\
[44] & MA-ABE & ✓ & ✓ & \(\times\) & ✓ \\
**Our Method** & **MA-CP-ABE** & ✓ & ✓ & ✓ & ✓ \\ \hline \hline \end{tabular}
\end{table}
Table 1: Summary of related work.  
access policy. The proposed scheme prevents the revoked user from accessing the newly generated data and the old data that can be accessed.  
However, the reported results are limited only to fog servers, and there is no security achievement for resource-constraint devices. Moreover, the authors did not describe multiauthority and attribute-revocation problems in the works above.