Homework 4
1.) (5 points) What are the roles of the public and private key?
A private key is kept private and is only known to the user. The private key can be
used to encrypt a signature that can be verified by anyone with the public key. A
public key is

Homework 4
1. What is a statistical database? Why might it be necessary to deny certain overlapping queries
from such databases?
Is a database that contains statistical data for example counts, averages and key figures.
One is pure statistical database wh

Lecture 4
Public Key Cryptography
Dr. ShaojieTang
[email protected]
Public Key Encryption
2
Public Key (Sender) Authentication
3
Public-Key Requirements
Public-Key Requirements
Public Key Algorithms
RSA (Rivest, Shamir, Adleman)
developed in 197

Lecture 6
Database Security
Dr. ShaojieTang
[email protected]
Overview
access control basics
access control lists
access control example: RDBMS
grant and revoke
grant options, cascading
role-based access control
inference attacks
counterme

Lecture 5
User/Message Authentication
Dr. ShaojieTang
[email protected]
Authentication
IPSec
protects against active attacks
verifies received message is authentic
contents unaltered
from authentic source
timely and in correct sequence
?
3
Ch

Homework 1
September 23, 2015
1. What is the difference between passive and active security threats?
Solutions: Passive attacks have to do with eavesdropping on, or monitoring, transmissions.
Electronic mail, file transfers, and client/server exchanges ar

Solutions to Homework 2
October 17, 2016
1. Why is it important to study the Feistel cipher?
Solutions: Most symmetric block encryption algorithms in current use are based on the
Feistel block cipher structure. Therefore, a study of the Feistel structure

Homework 3
Deadline: Oct 24th
1. (5 points) What does it mean to say that b is a divisor of a?
2. For each of the following equations, find an integer that satisfies the equation.
(a) (10 points) 5x = 4 (mod 3)
(b) (10 points) 7x = 6 (mod 5)
(c) (10 point

Solutions to Homework 3
October 26, 2016
1. (5 points) What does it mean to say that b is a divisor of a?
Solutions: A nonzero b is a divisor of a if a = mb for some m, where a, b, and m are integers.
That is, b is a divisor of a if there is no remainder

Homework 2
Deadline: October 11
1. (10 points) Why is it important to study the Feistel cipher?
2. (10 points) What is the difference between diffusion and confusion?
3. (15 points) Which parameters and design choices determine the actual algorithm of a F

Homework 1
Deadline: September 19
1. (5 points) What is the difference between passive and active security threats?
2. (5 points) List and briefly define categories of passive and active security attacks. Active
attacks: masquerade, replay, modification o

Homework 2
1.) Why is it important to study the Feistal cipher?
Its important to study the Feistal cipher because it proposes that we can
approximate the ideal block cipher by utilizing the concept of a product cipher,
which is the execution of two or mor

Homework 1
1. What is the difference between passive and active security threats?
Passive attack - attempts to learn or make use of information from the
system but does not affect system resources
Active attack attempts to alter system resources or affect

Homework 3
1. What does it mean to say that b is a divisor of a?
While having the knowledge of Divisibility and the Division Algorithm, saying
that b is a divisor of a means that b divides a; or that b is a divisor of a, more notated
by b|a
2. For each of