February 4, 2019 Critical Thinking

To enable secure outsourcing of file under the aforementioned model, our mechanism design should achieve the following security and performance guarantees:
No sensitive information from the customer’s private data can be derived by the cloud server during performing the encryption and transfer.
The local computations done by customer should be substantially less than. The computation burden on the cloud server should be within the comparable time complexity of existing practical algorithms for encryption and decryption of files.

Here the client sends the query to the server. Based on the query the server sends the corresponding file to the client. Then the client authorization is done by checking user id and password. In the server side, it checks the client name and its password for security process. If it is satisfied and then received the queries form the client and search the corresponding files in the database. Finally, find that file and send to the client. If the server finds the intruder means, it set the alternative Path to those intruders. If any intruders tries to access any file then multiple times password is asked to them and at last the intruders are directed to fake file. Here intruders will not know that the file he obtained is fake. They think that the file they got is original one.

Fig 4.1 System Architecture

The Data Flow Diagram(DFD) is also named as bubble chart diagram which is a simple graphical representation that can be used to represent a system. The system representation is done in terms of the input data to the system, the various processing carried out on these data, and the output data is generated by the system.

Fig 4.2 Data Flow Diagram

The sequence diagrams are an easy way of describing the system’s behavior. It focuses on the interaction between the system and the environment. This UML diagram shows the interaction arranged in a time sequence. It has two dimensions: the vertical dimension and the horizontal dimension. The vertical dimension used in UML sequence diagram represents the time and the horizontal dimension used represents the different objects. The vertical line is also called the object’s lifeline. It represents the object’s presence during the interaction.

Fig 4.3 Sequence Diagram


A use-case diagram is a graph of users or actors. It is a set of use cases enclosed by a system boundary which is also the participation associations between the actors and the use-cases, and generalization among the use cases.
So, the use-case is the description of the outside (actors or users) and inside(use-case) of the system’s typical behavior. An ellipse having the name is used to show the use case which is initiated by actors or users.
An Actor or a user is the one that communicates with a use-case. Name of the actors is written down and a arrow symbol is used to show the interaction between actor and use-case.