Write pseudocode for the password guessing algorithm, Computer Network Security

Write Pseudocode for the password guessing algorithm:

Consider the following authentication protocol:

Client

Transmission

Host

Explanation

U, user

U à

 

I am user U

 

ß {n, DES, SHA-1}

n, random challenge, DES, SHA-1

- I have SHA_1(P(U)), where P(U) is password of user U

 

- Here is a random challenge n, please use DES and SHA-1 to generate a response

r=DES(n, SHA-1(P))

U, rà

 

Response r is the encryption of the hash of the password P of user U using key n, DES for encryption, and SHA-1 for hashing.

 

 

ß yes/no

Compare: DES-1(n, r) to SHA_1(P(U))

Can the password of user U be obtained by using an offline password guessing attack? If your answer is yes, describe the attack and write pseudocode for the password guessing algorithm.  If your answer is no, describe why the protocol is resistant to an offline guessing attack.

2) Using RSA, perform an encryption then a decryption of the message M=5 using p=3, q=11, and e=7. (please add explanation, Show all your work, not just the final answer.)

3) You are the designer of a password security policy that requires passwords to expire once they have a probability of 0.001 of being guessed.  A potential attacker can test 1,000,000 passwords per second. If you chose passwords to be alphanumeric ("A" through "Z", "a" through "z", and "0" through "9"), what would you have to set the maximum lifetime of a password to in order to meet the required guessing probability (represent in days)?Assume the password size is 9 characters.

Posted Date: 2/15/2013 2:20:40 AM | Location : United States







Related Discussions:- Write pseudocode for the password guessing algorithm, Assignment Help, Ask Question on Write pseudocode for the password guessing algorithm, Get Answer, Expert's Help, Write pseudocode for the password guessing algorithm Discussions

Write discussion on Write pseudocode for the password guessing algorithm
Your posts are moderated
Related Questions
Question (a) Name 3 popular electronic mail access protocols? (b) i. What is DNS? ii. Briefly, describe what it does and how it works? iii. Why does DNS use a dist

Question: (a) Which of the following is not a goal of security: i) detection ii) prevention iii) recovery iv) prosecution (b) You are an honest student. One day you

Problem: (a) What is the minimum length of a password that could be considered to be "strong" in the context of today's computing power? (b) The security of a PIN system,


Unguided Media This is the wireless media that transfer electromagnetic waves without using a physical media. Waves are broadcast through the air. This is performing through r

Listing Assets in Order of Importance Weighting should be created for each category based on the answers to questions. The relative importance of each asset is calculated usin

Question: (a) Describe how IPSec provides data source authentication. (b) Which protocol can be used to provide limited traffic analysis confidentiality? Why is it "limite

802.11 WIRELESS LANs AND CSMA/CA:  IEEE 802.11 is standard wireless LAN that needs radio signals at 2.4GHz. Its speed is 11Mbps. The older computers use radio signals at data

Question: (a) Give 2 benefits of using IPsec. (b) IPSec uses two protocol for security: Authentication Header protocol (AH) and the Encapsulated Security Header Protocol (

Question requires you to produce a pcap file from a Wireshark capture.  In addition, you must include a screen capture of Wireshark and some specific information regarding the fram