网络安全代写 | ENGD3104 Communication Networks 2

这个作业是完成一个TCP问题和加密算法
ENGD3104 Communication Networks 2
Coursework Assignment II
2019-2020
TCP and Network Security
(Maximum Marks: 40)
Issue date: 30/03/2020
Submission deadline: 21/05/2020
Feedback date: 11/06/2020
What to submit: Your coursework must be submitted as a reportin Word format to Turnitin. All Matlab scripts used must be included as appendices at the end of the report. All code linesmust be commented to explain them.All sources used in the report must be cited as appropriate. All references must be in IEEE style. Please note that 2 markswill be allocated to the presentation and organisation of your report.

Part I) TCP

TCP uses Jacobson’s algorithm to update the timeout value. Write a Matlab function that takes the current estimate of the round-trip time and the latestacknowledgment time as input arguments and returns the timeout estimate as output.
(10 marks)

Research the literature to identify the limitations of Jacobson’s algorithm and briefly present alternative methods (500 words maximum).
(10 marks)

Part II) Network Security

Alice is communicating with Bob using the RSA algorithm. Bob’s public key is the pair(n=199956859, e=101).

Alice has sent the binary sequenceinFigure 1 (see next page) to Bob. You have intercepted this message. Decrypt it and give it as plain text in English. Clearly explain your answer.
(7 marks)
What are the weaknesses of the encryption used by Alice?
(3 marks)
Use Bob’s public key to encrypt the message: “John is a Spy” as a binary sequence.
(8 marks)
1 0 1 0 1 1 0 0 0 0 0 0 1 1 1 0 0 0 1 1 0 0 0 1 1 0 0 10 0 0 0 0 0 1 0 0 1 0 0 1 0 1 0 0 0 1 1 1 0 1 0 0 0 0 01 0 0 1 1 1 0 1 1 1 1 1 1 0 0 1 1 0 0 1 1 1 1 0 0 0 0 10 0 1 1 1 1 0 0 1 0 0 1 1 0 1 0 1 0 0 0 1 1 0 0 1 1 0 10 0 0 0 0 0 1 0 0 1 0 0 1 0 1 0 0 0 1 1 1 0 1 0 0 0 0 0
1 0 0 1 1 0 0 1 0 1 0 0 0 1 1 0 1 0 1 1 1 1 0 0 1 0 0 10 1 1 1 1 1 0 1 1 1 0 0 1 1 0 0 1 1 1 1 1 1 1 1 0 0 0 00 0 0 0 0 0 1 0 0 1 0 0 1 0 1 0 0 0 1 1 1 0 1 0 0 0 0 01 0 1 0 1 1 0 1 1 1 1 1 1 1 0 1 1 0 1 0 0 1 1 1 0 0 0 01 0 0 1 1 1 0 1 1 1 1 1 1 0 0 1 1 0 0 1 1 1 1 0 0 0 0 1
0 1 0 0 0 1 0 1 0 1 0 0 1 0 1 0 0 1 0 0
0 0 1 1 0 0 0 01 0 0 1 1 0 0 1 0 1 0 0 0 1 1 0 1 0 1 1 1 1 0 0 1 0 0 10 1 0 1 0 0 1 1 1 0 0 1 0 0 0 1 0 0 1 1 1 0 1 0 0 0 1 1

Figure 1: Alice’s message to Bob