CIPHER TEXT
CIPHER TEXT( COMPUTER SECURITY)
CS57
2
AH2 Computer Security Homework-3 Assignment SP 2021
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CS572AH2 Homework-3 Assignment |
Send your HW3 Report electronically |
Student’s Name: ___________________
Show all your work in detail for the highest grade. Good luck!
1. (15 pts.) Consider the mod 10 multiplication table (see the table on the right, below):
a. Which rows contain a value of 1? {in increasing numerical order} ____, ____, ____, ____.
b. These rows and no others contain a value of 1 because they are the only ones that are ________ to 10.
c. These numbers are significant for mod-10 arithmetic because only these numbers have ______, mod 10.
2. (10 pts.) [Fill out your answers {a function name and a number} directly in the text]:
In the Number Theory, two integers, n and m, are said to be relatively prime (or co-primes) when their ____(n, m) {a function} = _____{a number}.
3. (10 pts.) [Message Authentication Codes]
Bob sends a message to Alice. He sends the message in plaintext, but first he uses a Message Authentication Code (MAC), with a secret key he shares with Alice, to create a cryptographic checksum for the message. He sends the cryptographic checksum along with the message.
Upon receipt of the message, Alice uses the same MAC algorithm and key to generate a cryptographic checksum. She compares the two checksums and finds them to be identical.
As a result, what two things is Alice assured of about the message? _______________
What is she
not
assured of? ______________________
4. (15 pts.) What is the essential difference between a worm and a virus?
Your Answer: _________________
5. (15 pts.) [Fill out your answers directly in the text]: Sometimes, web pages contain tiny images, too small to be visible to the user. Such an image is called a ___________, and its purpose is to convey information to a web server operated by a company that ___________ your navigation through the web.
6. (20 pts.) [TRUE or FALSE]
The following are examples of a
secret key (symmetric) block cipher
{put TRUE or FALSE}:
a. The
Advanced Encryption Standard
___________
b.
Blowfish ___________
c. The
Caesar Cipher
___________
d.
The Data Encryption Standard ___________
e.
IDEA ___________
f.
MD5 ___________
g.
The Playfair Cipher ___________
h.
RSA
___________
7. (15 pts.) [Authentication] Which of the following are good choices for a secure password? {put GOOD or BAD}
a. admin ___________
b. 4seasons ___________
c. KMLairline ___________
d. The9%Queen^! ___________
e. Gomamgo ___________
f. asix49lakesize ___________
g. ElvisPresley ___________
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