CIS3360: Security In Computing 2
Download this Homework Answers covering key security principles in computing.
Emma Taylor
Contributor
4.3
51
about 1 month ago
Preview (3 of 7)
Sign in to access the full document!
CIS3360: Security in Computing
Homework 5
1. ( 15 points) Knowledge-based Question:
a. What are the differences between public/symmetric key cryptography? The advantage
and disadvantage of each?
a. For English alphabet based texts regardless of upper or lower case (i.e., assuming each
letter has only 26 possible value), if the length of the key using Vigenere Cipher is 4, how
many possible encryption keys exist? (hint: we all know that Caesar cipher has 26
possible encryption keys)
b. What is the usage of a cryptographic hash function? Can two documents have the same
hash value?
Answer:
1. Public vs Symmetric Key Cryptography
• Public Key (Asymmetric):
o Uses two keys: public (shared) and private (secret).
o Advantages: Easier key distribution, non-repudiation.
o Disadvantages: Slower, more computationally intensive.
• Symmetric Key:
o Uses one key for both encryption and decryption.
o Advantages: Faster, simpler.
o Disadvantages: Key distribution is harder, not scalable.
2. Vigenère Cipher with Key Length 4
• There are 26^4 = 456,976 possible encryption keys.
3. Cryptographic Hash Function
• Usage: Ensures data integrity, stores passwords securely, creates digital signatures.
• Collisions: While rare, two documents can technically have the same hash value (this is
called a collision).
Homework 5
1. ( 15 points) Knowledge-based Question:
a. What are the differences between public/symmetric key cryptography? The advantage
and disadvantage of each?
a. For English alphabet based texts regardless of upper or lower case (i.e., assuming each
letter has only 26 possible value), if the length of the key using Vigenere Cipher is 4, how
many possible encryption keys exist? (hint: we all know that Caesar cipher has 26
possible encryption keys)
b. What is the usage of a cryptographic hash function? Can two documents have the same
hash value?
Answer:
1. Public vs Symmetric Key Cryptography
• Public Key (Asymmetric):
o Uses two keys: public (shared) and private (secret).
o Advantages: Easier key distribution, non-repudiation.
o Disadvantages: Slower, more computationally intensive.
• Symmetric Key:
o Uses one key for both encryption and decryption.
o Advantages: Faster, simpler.
o Disadvantages: Key distribution is harder, not scalable.
2. Vigenère Cipher with Key Length 4
• There are 26^4 = 456,976 possible encryption keys.
3. Cryptographic Hash Function
• Usage: Ensures data integrity, stores passwords securely, creates digital signatures.
• Collisions: While rare, two documents can technically have the same hash value (this is
called a collision).
Preview Mode
Sign in to access the full document!
100%
Study Now!
XY-Copilot AI
Unlimited Access
Secure Payment
Instant Access
24/7 Support
Document Chat
Document Details
University
University of South Florida
Subject
Information Technology