## 3 Proposed Framework for Cloud Multi-Factor Multi-Layer Authentication
### Authentication Method Selector (AMS)  
The AMS manages the authentication technique to be applied primarily to user behavior prediction. Various authentication techniques can be used or added according to business needs and according to the regulations of the organization. Some organizations can provide fingerprint authentication, while others can provide security tokens. The selection process for any technique depends on the role of the organization, the tools available, and the sensitivity degree through which different multi-factor methods are adapted and applied to secure confidential data. The application administrators are responsible for adding and choosing the authentication techniques used. This paper provides additional authentication methods like SMS, security token via email, and biometric authentication using fingerprint. Assume a _user\({}_{k}\)_ wants to access the cloud application and forget her/his username-password credentials, s/he will be authenticated using her/his email for the first time of authentication. For the next login process on the cloud application platform, s/he must be authenticated using a different method like SMS or fingerprint authentication to ensure the user's identity in case of email disclosure. The process of selecting an authentication method is based on three main steps. These steps are the user's last authentication method, authentication method priority, and the authentication process status. In the user's last authentication method step, three methods of authentication are selected: security token via email, SMS, and fingerprint authentication. Before authenticating the user, a request is directed to the cloud database server to obtain the last authentication method that was used in the last authentication process. The second step defines the applied authentication method, where a priority table is defined to determine the usage priority for each authentication method. Each method is assigned a number that defines its priority. The priority of the authentication mechanism increases with the number, and vice versa. Changes to the requirements and organizational regulations can easily be made to this priority. The authentication method is selected depending on the percentage of usage. This percentage is calculated by dividing the number of usage times of each authentication method by the sum of all authentication times. The priority in the authentication method table can be changed according to the security measures of the organization. Furthermore, additional authentication methods can be added to the priority-level table. Table 2 represents the priority table for the proposed authentication method. The third step for defining the authentication is implemented by using the status step for the user authentication process. After selecting the authentication method, the first authentication layer using security token via email is applied. Based on the result of the first authentication process, an additional authentication layer is added. If the first layer is true, the user will be authentic and will have the privileges to access cloud services. Otherwise, the SMS is selected to be the next authentication method. The mechanism will continue until the last layer of authentication. As shown in Table 3, the selection of the authentication method is based on the importance of the method in the priority table. Based the authentication methods applied to \(user_{i}\), the security token via email have 38.46% while the SMS and fingerprint authentication both have percentage usage of 30.77%. Therefore, the next authentication method will be selected between SMS and fingerprint authentication. Due to the high priority of SMS over fingerprint authentication based on the priority table, the next authentication method will be SMS. The authentication method for \(user_{j}\) contains 35.71% for both security tokens via email and SMS, while fingerprint authentication has 30.77% usage.