CS204 Assignment 2 Spring 2021
Assignment No. 02
Semester: Spring 2021
Total Marks: 10
Due Date: 08 June 2021
● The objective of this assignment is to enhance the knowledge of the students about:
o Cryptography techniques
o Categories and types of Cybercrimes.
● Your assignment must be in .doc or .docx format (Any other formats like scan images, pdf, bmp, etc will not be accepted).
● Save your assignment with your ID (e.g. bc020200786.doc).
● No assignment will be accepted through email.
Rules for Marking:
It should be clear that your assignment will not get any credit if:
● The assignment is submitted after due date.
● The submitted assignment does not open or file is corrupted.
● Your assignment is copied from internet, handouts or from any other student
● Assignment is covered from lectures 03 to 05.
For any query about the assignment, contact at email@example.com
Questions: Marks 15
Question 1 (Marks 5)
Use the Caesar cipher encryption method to the given word with shift key of 4 and show the complete process with each step included.
shift key of 4, we get
Where A=E, B=F, C=G, D=H, E=I, F=J, G=K, H=L, I=M, J=N, K=O, L=P, M=Q, N=R, O=S, P=T, Q=U, R=V, S=W, T=X, U=Y, V=Z, W=A, X=B, Y=C, Z=D
Plaintext: – DIRECTATTACK
Key: – 4
DIRECTATTACK encrypt as
D=H, I= M, R= V, E=I, C=G, T=X, A=E, T=X, T=X, A=E, C=G, K=O
Cipher Text: HMVIGXEXXEGO
Question 2 (Marks 5)
Suppose your computer is infected with some kind of virus from internet free ads. That virus collects your G-mail credentials and sends bulk of emails to the multiple recipients with fake lottery ticket ads. Any recipient who clicks on the link or attachment also gets infected too.
Considering the above scenario, answer the following questions:
1) What type of Cybercrime(s) do you observe in this scenario?
2) What are the preventive measures that can be taken to avoid it?
Here are five simple ways to fight spam and to protect yourself online:
● Never give out or post your email address publicly.
● Think before you click.
● Do not reply to spam messages.
● Download spam filtering tools and anti-virus software.
● Avoid using your personal or business email address.
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