ComputerScienceExpert

(11)

$18/per page/

About ComputerScienceExpert

Levels Tought:
Elementary,Middle School,High School,College,University,PHD

Expertise:
Applied Sciences,Calculus See all
Applied Sciences,Calculus,Chemistry,Computer Science,Environmental science,Information Systems,Science Hide all
Teaching Since: Apr 2017
Last Sign in: 5 Weeks Ago, 4 Days Ago
Questions Answered: 4870
Tutorials Posted: 4863

Education

  • MBA IT, Mater in Science and Technology
    Devry
    Jul-1996 - Jul-2000

Experience

  • Professor
    Devry University
    Mar-2010 - Oct-2016

Category > Programming Posted 25 Apr 2017 My Price 9.00

Consider Diffie-Hellman scheme

 

1) Consider Diffie-Hellman scheme with a common prime q = 11 and a primitive root α = 2. **Step by step***

a. Show that 2 is a primitive root of 11?

b. If used A has public key YA = 9, what is A’s private key XA?

c. If used B has public key YB = 3, what is secret key K shared with A?

 

2) This problem illustrates the point that the Diffie-Hellman protocol is not secure without the step where you take the modulus; i.e. the “Indiscrete Log Problem” is not a hard problem! You are Eve and have captured Alice and Bob and imprisoned them. You overhear the following dialog.

 

Bob: Oh, let’s not bother with the prime in the Diffie-Hellman protocol, it will make things easier.

Alice: Okay, but we still need a base α to raise things to. How about α = 3? 

Bob: All right, then my result is 27.

Alice: And mine is 243.

 

What is Bob’s private key XB and Alice’s private key XA? What is their secret combined key? (Please give me step by step)

 

3) Why does MD5 require padding of messages that are already a multiple of 512 bits? Explain

 

4) Message digests are reasonably fast, but consider the following faster function: take your message, divide into 128-bit chunks, and ⊕ (XOR) all the chunks to get to get a 128-bit result. Then compute your message digest on the result. Would this be a good message digest function? Explain.

 

5) Explain in detail how Message Authentication Code is used to help verify the integrity of the message in this example (click on link below and scroll down to where it says "An Example of Message Authentication Code Algorithm"):  https://en.wikipedia.org/wiki/Message_authentication_code#An_Example_of_Message_Authenti cation_Code_Algorithm

 

Answers

(11)
Status NEW Posted 25 Apr 2017 05:04 AM My Price 9.00

-----------

Not Rated(0)